MultimediaWiki - Recent changes [en]

FFmpeg Summer of Code 2013

2013-03-06T19:16:07Z

subtitles: expected results as bullet points

Revision as of 19:16, 6 March 2013		Current revision
Line 148:		Line 148:
	'''Qualification task:''' write or port one or more filter		'''Qualification task:''' write or port one or more filter

-	'''Mentor:''' Stefano Sabatini (''saste'' on IRC).	+	'''Mentor:''' Stefano Sabatini (''saste'' on IRC). Backup: Clément Bœsch (''ubitux'' on IRC).
		+
		+	=== Subtitles ===
		+
		+	'''Description:''' FFmpeg has been working on improving its subtitles support recently, notably by adding the support for various text subtitles and various hardsubbing (burning the subtitles onto the video) facilities. While the theme may sound relatively simple compared to audio/video signal processing, the project carry an historical burden not easy to deal with, and introduces various issues very specific to its sparse form.
		+
		+	'''Expected results:'''
		+	* Write the support for new subtitles formats. Example: a demuxer for .SUP files, just like VobSub but for Blu-Ray.
		+	* Improve text subtitles decoders. Typically, this can be supporting advanced markup features in SAMI or WebVTT.
		+	* Improve the API to facilitates a proper integration of subtitles into libavfilter.
		+
		+	'''Prerequisites:''' C coding skills, familiarity with git/source code control systems. Some background in fansubbing area (notably ASS experience) would be a bonus but is not strictly required.
		+
		+	'''Qualification task:''' write one subtitles demuxer or muxer, and do some improvements to the different layers of the subtitles (to make sure the whole chain is understood).
		+
		+	'''Mentor:''' Clément Bœsch (''ubitux'' on IRC).

	[[Category:FFmpeg]]		[[Category:FFmpeg]]

User:Adam Quantrill

2013-03-05T18:09:26Z

New page

Adam is a computing and electronics engineer currently working in Telecoms, specifically GSM basestations at IP Access Ltd near Cambridge, UK.

Hobbies include engineering, electronics, computing and fine real ale.

AMR-NB

2013-03-05T18:06:26Z

/* GSM OTA format */

Revision as of 18:06, 5 March 2013		Current revision
Line 34:		Line 34:

	== Bit stream frame format ==		== Bit stream frame format ==
-	Specification ([http://www.3gpp.org/ftp/Specs/html-info/26101.htm 26.101]) describes two possible frame types - interface formats 1 and 2 (often abbreviated IF1 and IF2). IF2 is byte-aligned. The following tables of data are taken from this specification unless otherwise stated.	+	Specification ([http://www.3gpp.org/ftp/Specs/html-info/26101.htm 26.101]) describes two possible frame types - interface formats 1 and 2 (often abbreviated IF1 and IF2). IF2 is byte-aligned. The following tables of data are taken from this specification unless otherwise stated. AMR-NB over GSM uses a third slightly different format whose bit-packing is tightly defined by the GSM specs.

	=== IF1 format ===		=== IF1 format ===
Line 91:		Line 91:
	\| Padding (called "Bit stuffing" in the specification)		\| Padding (called "Bit stuffing" in the specification)
	\|		\|
		+	\|}
		+
		+	=== GSM OTA format ===
		+
		+	{\| border=1
		+	! bits !! low level meaning \|\| high level meaning
		+	\|-
		+	\| 4
		+	\| Mode request
		+	\| rowspan=1 \| AMR auxiliary information
		+	\|-
		+	\| 1
		+	\| F bit (0 good/1 unusual)
		+	\| rowspan=3 \| AMR header
		+	\|-
		+	\| 4
		+	\| Frame Type
		+	\|-
		+	\| 1
		+	\| Frame quality indicator (0 bad/1 good)
		+	\|-
		+	\|
		+	\| Class A bits
		+	\| rowspan=3 \| AMR core frame
		+	\|-
		+	\| 6
		+	\| CRC
		+	\|-
		+	\|
		+	\| Class B bits
	\|}		\|}

Line 140:		Line 170:

	* Class A is protected by an 8-bit CRC with polynomial x^8+x^6+x^5+x^4+1 computed over the Class A bits.		* Class A is protected by an 8-bit CRC with polynomial x^8+x^6+x^5+x^4+1 computed over the Class A bits.
		+	* However for AMR-NB over GSM the CRC is a 6-bit with polynomial x^6+x^5+x^3+x^2+x+1 computed over the Class A bits, and it immediately follows the Class A bits, rather than preceding them. That is, it's between the Class A and Class B bits. [see 3GPP TS 05.03 sec 3.9.4.3]
	* There is no significant step-wise change in subjective importance at class boundaries.		* There is no significant step-wise change in subjective importance at class boundaries.
	* The distribution of bits is ordered from most to least subjective importance at both the class level and within the classes.		* The distribution of bits is ordered from most to least subjective importance at both the class level and within the classes.

Talk:SGA

2013-03-03T23:11:11Z

New page

===32x File Format===

I disassembled the nt.bin and subload.bin, looks like most of the decoding is done on the 68k side, rather than the sh2 (32x) side.

I will document my curiosities here, for others to read.

==Special Values in decoding==
If the y tile size is 11 then special values are 01 and 03, otherwise its 04 and 02. Havent found where its used yet. But those values pop up all over the compressed data.

LAB_0289:
move #$0003,d3 ;6390: 363C0003
move #$0001,d4 ;6394: 383C0001
cmpi.b #$11,EXT_000D ;6398: 0C390011002018FF
beq.s LAB_028A ;63A0: 6708
move #$0002,d3 ;63A2: 363C0002
move #$0004,d4 ;63A6: 383C0004
LAB_028A:
rts ;63AA: 4E75

==Possible code book setup==
I think this code here is setting up a code book, whats interesting that it seeks to a specific location. Plus there is a specific code book size.

adda.l #$00003004,a0 ;6010: D1FC00003004
movea.l EXT_016B.w,a1 ;6016: 2278AA66
adda.l #$00003020,a1 ;601A: D3FC00003020
move #$1800,d0 ;6020: 303C1800
bsr LAB_0281 ;6024: 610001EC

Scream Tracker 3 Module

2013-03-03T02:13:53Z

/* File Format */ Mention how wide parapointers are

Revision as of 02:13, 3 March 2013		Current revision
Line 8:		Line 8:
	==File Format==		==File Format==

-	The format is little-endian (least significant byte first). A "byte" is 8 bits, a "word" is 16 bits, and a "dword" (double word) is 32 bits. Hex values will be denoted with "0x". A parapointer points to pp*16 in the file due to the DOS nature of the format.	+	The format is little-endian (least significant byte first). A "byte" is 8 bits, a "word" is 16 bits, and a "dword" (double word) is 32 bits. Hex values will be denoted with "0x". A parapointer is 16 bits wide, and points to pp*16 in the file due to the DOS nature of the format.

	Note that if some parts of the format are inconsistent, it's usually best to let it slip, as ST3 itself will allegedly for instance load instruments which don't have the "SCRS" / "SCRI" mark.		Note that if some parts of the format are inconsistent, it's usually best to let it slip, as ST3 itself will allegedly for instance load instruments which don't have the "SCRS" / "SCRI" mark.

User:Compn

2013-02-28T18:09:12Z

/* unknown codec */

Revision as of 18:09, 28 February 2013		Current revision
Line 184:		Line 184:
	[[User:Dashcloud\|Dashcloud]] 14:23, 20 February 2009 (EST)		[[User:Dashcloud\|Dashcloud]] 14:23, 20 February 2009 (EST)
	HHE1 - zvue video? hhe0 / hhe1 patent : http://www.freepatentsonline.com/y2007/0019741.html . looks like modified mpeg4.		HHE1 - zvue video? hhe0 / hhe1 patent : http://www.freepatentsonline.com/y2007/0019741.html . looks like modified mpeg4.
		+	.
		+	official website in archive hheld.com zvue.com
		+	zflicks 1.5 encodes to xvid, included with ZOrgInstall-1.0.1.exe
		+	all of the -zvue.avi files are created with zflicks 1.1 , but zflicks 1.1 does not include the hhe0 or hhe1 codec. only divx.dll (comes with 1.1) or xvid (comes with 1.5).
		+
		+
	speg - http://qstream.org/ appears to be an Xvid derivative- if you check out the source code, there's a patch mplayer-speg.patch		speg - http://qstream.org/ appears to be an Xvid derivative- if you check out the source code, there's a patch mplayer-speg.patch
	which just tacks SPEG onto all the xvid stuff. [[User:Dashcloud\|Dashcloud]] 14:23, 20 February 2009 (EST)		which just tacks SPEG onto all the xvid stuff. [[User:Dashcloud\|Dashcloud]] 14:23, 20 February 2009 (EST)

Summer of code

2013-02-27T18:41:06Z

fix redirect

Revision as of 18:41, 27 February 2013		Current revision
Line 1:		Line 1:
-	#redirect [[FFmpeg Summer Of Code]]	+	#redirect [[FFmpeg_/_Libav_Summer_Of_Code]]

FFmpeg Summer of Code 2013

2013-02-27T18:38:24Z

remove g2m task, 3 months is not enough time to reverse engineer and finish a spec.

Revision as of 18:38, 27 February 2013		Current revision
Line 57:		Line 57:

	== Video codecs ==		== Video codecs ==
-
-	=== GotoMeeting Decoder ===
-
-	'''Description:''' The [[GoToMeeting_Codec]] has been figured out and we need a decoder for it. We don't have samples for G2M1 so this decoder will focus on G2M2, G2M3 and G2M4 versions.

	=== HEVC / H265 ===		=== HEVC / H265 ===

MO3

2013-02-25T20:12:05Z

New page

* created by Ian Luck (http://www.un4seen.com/)
* Amiga / PC modules with lossless, MP3 or OGG compression
* (un)official specifications and open source decoder : http://lclevy.free.fr/mo3/

FFmpeg Summer of Code 2013

2013-02-25T09:46:07Z

/* Animated Portable Network Graphics (APNG) */

Revision as of 09:46, 25 February 2013		Current revision
Line 110:		Line 110:
	** write compliant files, make sure they play correctly in major web browsers that support APNG		** write compliant files, make sure they play correctly in major web browsers that support APNG
	** add test for FATE		** add test for FATE
-
-	'''Mentor: [[User:Pbm\|Paul B Mahol]]'''

	'''Prerequisites:''' C coding skills, familiarity with git/source code control systems.		'''Prerequisites:''' C coding skills, familiarity with git/source code control systems.
		+
		+	'''Qualification Task:''' Implement format autodetection for imagepipe & image demuxer
		+
		+	'''Mentor: [[User:Pbm\|Paul B Mahol]]'''

	=== JPEG 2000 ===		=== JPEG 2000 ===

Libav Summer Of Code 2013

2013-02-24T19:17:11Z

The Grand Refactoring project idea

Revision as of 19:17, 24 February 2013		Current revision
Line 79:		Line 79:

	You will require skills in POSIX shell, GNU Make and a firm command of English.		You will require skills in POSIX shell, GNU Make and a firm command of English.
		+
		+	''Mentor: [[User:DonDiego\|Diego Biurrun]]''
		+
		+	=== The Grand Refactoring (working title) ===
		+
		+	Many parts of the libav codebase are still unnecessarily monolithic. This makes custom builds that only support a subset of the multitude of formats we have larger than they need to be. The goal of this project will be to locate parts that can be separated and refactor the code so that each subpart can be compiled standalone so as to not increase the size of a custom configuration without the part.
		+
		+	A suitable qualification task for this project is picking a simple encoder/decoder pair or some part of dsputil (harder) and splitting it cleanly.
		+
		+	Note that this project will consist of multiple small subtasks and is therefore highly parallelizable. More than one student could apply for and work on this at the same time, each on different subtasks.

	''Mentor: [[User:DonDiego\|Diego Biurrun]]''		''Mentor: [[User:DonDiego\|Diego Biurrun]]''

FFmpeg Summer of Code 2013

2013-02-23T15:42:42Z

/* JPEG 2000 */

Revision as of 15:42, 23 February 2013		Current revision
Line 118:		Line 118:

	'''Description:''' FFmpeg contains an experimental native JPEG 2000 encoder and decoder. Both are missing many features, see also the FFmpeg bug tracker for some unsupported samples.		'''Description:''' FFmpeg contains an experimental native JPEG 2000 encoder and decoder. Both are missing many features, see also the FFmpeg bug tracker for some unsupported samples.
-	Work on an issue as a qualification task to show that you are capable of improving the codec implementation.	+	Work on an issue (for example from the bug tracker) as a qualification task to show that you are capable of improving the codec implementation.

	=== VP7 ===		=== VP7 ===

FFmpeg Summer of Code 2013

2013-02-23T13:36:32Z

/* Animated Portable Network Graphics (APNG) */

Revision as of 13:36, 23 February 2013		Current revision
Line 89:		Line 89:
	'''Expected results:'''		'''Expected results:'''
	* APNG demuxer		* APNG demuxer
-	** implement robust probing, so that normal PNG images are not misdetected as APNG animations	+	** implement robust probing:
		+	*** PNG images are not misdetected as APNG animations
		+	*** APNG animations are not misdetected as PNG images
	** splits stream into sensible packets (so they can be easily reused in APNG muxer)		** splits stream into sensible packets (so they can be easily reused in APNG muxer)
	** survives fuzzing (zzuf)		** survives fuzzing (zzuf)
	** add FATE coverage, coverage should be at least 70%		** add FATE coverage, coverage should be at least 70%
-	** test code under valgrind so not invalid reads/writes happen	+	** test code under valgrind so no invalid reads/writes happen

	* APNG decoder		* APNG decoder
Line 102:		Line 104:
	** add test for FATE, coverage should be at least 75%		** add test for FATE, coverage should be at least 75%
	** CRC checksum validation		** CRC checksum validation
-	** test code under valgrind so not invalid reads/writes happen	+	** test code under valgrind so no invalid reads/writes happen

	* APNG muxer && APNG encoder		* APNG muxer && APNG encoder
		+	** use existing PNG encoder code (write encoder in same file)
	** write compliant files, make sure they play correctly in major web browsers that support APNG		** write compliant files, make sure they play correctly in major web browsers that support APNG
		+	** add test for FATE

	'''Mentor: [[User:Pbm\|Paul B Mahol]]'''		'''Mentor: [[User:Pbm\|Paul B Mahol]]'''

Libav Summer Of Code 2013

2013-02-23T12:46:13Z

/* Hardware Acceleration API */

Revision as of 12:46, 23 February 2013		Current revision
Line 27:		Line 27:
	=== Hardware Acceleration API ===		=== Hardware Acceleration API ===

-	Libav has two different and incomplete APIs to provide hardware acceleration wrapping. The project should improve the available abstraction, migrate the currently implemented ones and add more hardware acceleration interfaces.	+	Libav has two different and incomplete APIs to provide hardware acceleration wrapping. One, deprecated, is to make a full decoder and signal its capabilities somehow, the other integrates in the stock decoder, has some provision for transparent fallback, but lacks a clean way to setup and pass configuration options to it.
		+
		+	The project should improve the available abstraction, migrate the currently implemented ones and add more hardware acceleration interfaces.

	* Draft the API (that will require knowledge of libavcodec).		* Draft the API (that will require knowledge of libavcodec).
Line 41:		Line 43:
	The WebM team is refining the evolution of their VP8 codec using a number of additional tools and tunings. The project involves providing a baseline		The WebM team is refining the evolution of their VP8 codec using a number of additional tools and tunings. The project involves providing a baseline
	decoder as first step and optimizing it to be at least as fast as the libvpx one on one of the most used architectures (ARM and x86_64).		decoder as first step and optimizing it to be at least as fast as the libvpx one on one of the most used architectures (ARM and x86_64).
		+
		+	[http://tools.ietf.org/html/draft-grange-vp9-bitstream-00 current draft]

	'''Mentor: [[User:lu_zero\|Luca Barbato]]'''		'''Mentor: [[User:lu_zero\|Luca Barbato]]'''

FFmpeg Summer of Code 2013

2013-02-23T02:06:32Z

/* VP7 */ I did believe that the available specification was released by Google, it appears that this is incorrect

Revision as of 02:06, 23 February 2013		Current revision
Line 118:		Line 118:
	=== VP7 ===		=== VP7 ===

-	'''Description:''' Not many VP7 samples are in the wild, but no open-source decoder exists although Google has released a specification. Write a decoder that reuses as much as possible of existing FFmpeg code, it is likely that functions of the existing decoders for On2-based formats will be useful.	+	'''Description:''' Not many VP7 samples are in the wild, but no open-source decoder exists although a specification exists. Write a decoder that reuses as much as possible of existing FFmpeg code, it is likely that functions of the existing decoders for On2-based formats will be useful.

	== Other ==		== Other ==

FFmpeg Summer of Code 2013

2013-02-22T18:57:52Z

/* DTS / DCA */ please cehoyos refrain from editing something you do not know anything about, DTS-HD is just fancy name for couple of DTS extensionsm, there is already suport for some DTS-HD features

Revision as of 18:57, 22 February 2013		Current revision
Line 34:		Line 34:

	'''Description:''' FFmpeg contains a DTS decoder and an experimental DTS encoder. Both are missing some features.		'''Description:''' FFmpeg contains a DTS decoder and an experimental DTS encoder. Both are missing some features.
-	* DTS-HD decoder: A possible qualification task is to implement ticket #1920	+	* DTS-HD decoder improvements: A possible qualification task is to implement ticket #1920
-	** Add support for mixed Core + DTS-HD stream structure	+
	** Add support for X96 extension (96khz)		** Add support for X96 extension (96khz)
	** Add support for XLL extension (lossless)		** Add support for XLL extension (lossless)
	** Add support for pure DTS-HD streams that do not contain a DTS core		** Add support for pure DTS-HD streams that do not contain a DTS core
	** Add support for multiple assets		** Add support for multiple assets
-	* DTS decoder improvements
	** Add support for LBR extension		** Add support for LBR extension
	* DTS encoder improvements		* DTS encoder improvements

FFmpeg Summer of Code 2013

2013-02-22T18:13:54Z

/* GSoC task proposal ideas */ Redesign layout

Revision as of 18:13, 22 February 2013		Current revision
Line 17:		Line 17:
	'''Mentor:''' List mentor and backup mentor if there is one and contact info such as IRC name or email address.		'''Mentor:''' List mentor and backup mentor if there is one and contact info such as IRC name or email address.

-	= GSoC Ideas =	+	= GSoC task proposal ideas =

	== Audio codecs ==		== Audio codecs ==
Line 122:		Line 122:
	'''Description:''' Not many VP7 samples are in the wild, but no open-source decoder exists although Google has released a specification. Write a decoder that reuses as much as possible of existing FFmpeg code, it is likely that functions of the existing decoders for On2-based formats will be useful.		'''Description:''' Not many VP7 samples are in the wild, but no open-source decoder exists although Google has released a specification. Write a decoder that reuses as much as possible of existing FFmpeg code, it is likely that functions of the existing decoders for On2-based formats will be useful.

-	=== FFplay ===	+	== Other ==

-	==== glplay ====	+	=== glplay ===

	'''Description:''' The SDL library that is used by FFplay has some deficiencies, adding OpenGL output to FFplay should allow for better performance (and less bugs at least for some hardware / driver combinations). This could be a new application (glplay), but it is probably simpler to extend ffplay to use OpenGL. You can use code from MPlayer's OpenGL vo module which may be relicensed under the LGPL.		'''Description:''' The SDL library that is used by FFplay has some deficiencies, adding OpenGL output to FFplay should allow for better performance (and less bugs at least for some hardware / driver combinations). This could be a new application (glplay), but it is probably simpler to extend ffplay to use OpenGL. You can use code from MPlayer's OpenGL vo module which may be relicensed under the LGPL.

-	=== Libavfilter extension ===	+	=== Misc Libavfilter extension ===

-	'''Description:''' Libavfilter is the FFmpeg filtering library that started as a 2007 SoC [[FFmpeg Summer Of Code#Video Filter API (AKA libavfilter)\|project]]. It currently supports audio and video filtering and generation support.	+	'''Description:''' Libavfilter is the FFmpeg filtering library. It currently supports audio and video filtering and generation support. This work may focus on porting, fixing, extending, or writing new audio and video filters from scratch.

-	* This work may focus on porting MPlayer filters which are currently integrated through the mp wrapper.	+	Candidate filters for porting may be the remaining MPlayer filters currently supported through the mp wrapper, libaf MPlayer filters, and filters from other frameworks (e.g. mjpegtools, transcode, avisynth, virtualdub, etc.). In case of mp ports, the student should verify that the new filter produces the same output and is not slower.
-	* For each port the student should verify that the new filter produces the same output and checking that the new integrated filter is not slower.	+
-	* For more ideas read the [[FFmpeg_/_Libav_Summer_Of_Code_2011#Libavfilter_video_work\|GSoC 2011 libavfilter video proposal]] and [https://ffmpeg.org/trac/ffmpeg/query?status=new&status=open&status=reopened&component=avfilter&col=id&col=summary&col=status&col=type&col=priority&col=component&col=version&order=priority trac libavfilter tickets].	+

-	'''Expected results:''' Write or port audio and video filters and possibly fix/extend libavfilter API and design.	+	Some ideas for more filters:
		+	* a frequency filtering domain filter relying on the FFT utils in libavcodec
		+	* a controller filter which allows to send commands to other filters (e.g. to adjust volume, contrast, etc.), e.g. like the sendcmd filter but through an interactive GUI
		+	* a lua scripting filter, which allows to implement filtering custom logic in lua
		+
		+	For more ideas check:
		+	[https://ffmpeg.org/trac/ffmpeg/query?status=new&status=open&status=reopened&component=avfilter&col=id&col=summary&col=status&col=type&col=priority&col=component&col=version&order=priority trac libavfilter tickets].
		+
		+	'''Expected results:''' Write or port audio and video filters and possibly fix/extend libavfilter API and design when required.

	'''Prerequisites:''' C coding skills, familiarity with git/source code control systems. Some background on DSP and image/sound processing techniques would be a bonus but is not strictly required.		'''Prerequisites:''' C coding skills, familiarity with git/source code control systems. Some background on DSP and image/sound processing techniques would be a bonus but is not strictly required.
		+
		+	'''Qualification task:''' write or port one or more filter

	'''Mentor:''' Stefano Sabatini (''saste'' on IRC).		'''Mentor:''' Stefano Sabatini (''saste'' on IRC).

	[[Category:FFmpeg]]		[[Category:FFmpeg]]

FFmpeg Summer of Code 2013

2013-02-22T14:44:21Z

/* DTS / DCA */

Revision as of 14:44, 22 February 2013		Current revision
Line 34:		Line 34:

	'''Description:''' FFmpeg contains a DTS decoder and an experimental DTS encoder. Both are missing some features.		'''Description:''' FFmpeg contains a DTS decoder and an experimental DTS encoder. Both are missing some features.
-	* DTS-HD decoder improvements: A possible qualification task is to implement ticket #1920	+	* DTS-HD decoder: A possible qualification task is to implement ticket #1920
	** Add support for mixed Core + DTS-HD stream structure		** Add support for mixed Core + DTS-HD stream structure
	** Add support for X96 extension (96khz)		** Add support for X96 extension (96khz)
Line 40:		Line 40:
	** Add support for pure DTS-HD streams that do not contain a DTS core		** Add support for pure DTS-HD streams that do not contain a DTS core
	** Add support for multiple assets		** Add support for multiple assets
		+	* DTS decoder improvements
	** Add support for LBR extension		** Add support for LBR extension
	* DTS encoder improvements		* DTS encoder improvements
Line 72:		Line 73:
	=== H264 MVC ===		=== H264 MVC ===

-	'''Description:''' MVC samples exist (somewhere? link!?), the codec is used on Bluray media, FFmpeg is missing a decoder. Since this task also consists of some changes in the current architecture, it is especially important that this task is discussed on the ffmpeg-devel mailing list.	+	'''Description:''' MVC samples exist, the codec is used on Bluray media, FFmpeg is missing a decoder. Since this task also consists of some changes in the current architecture, it is especially important that this task is discussed on the ffmpeg-devel mailing list.
	As qualification you have to do some work that demonstrates your understanding of MVC and that is a subpart of the whole MVC implementation.		As qualification you have to do some work that demonstrates your understanding of MVC and that is a subpart of the whole MVC implementation.

FFmpeg Summer of Code 2013

2013-02-22T12:49:52Z

/* Video codecs */ add gotomeeting task

Revision as of 12:49, 22 February 2013		Current revision
Line 58:		Line 58:

	== Video codecs ==		== Video codecs ==
		+
		+	=== GotoMeeting Decoder ===
		+
		+	'''Description:''' The [[GoToMeeting_Codec]] has been figured out and we need a decoder for it. We don't have samples for G2M1 so this decoder will focus on G2M2, G2M3 and G2M4 versions.

	=== HEVC / H265 ===		=== HEVC / H265 ===
Line 68:		Line 72:
	=== H264 MVC ===		=== H264 MVC ===

-	'''Description:''' MVC samples exist, the codec is used on Bluray media, FFmpeg is missing a decoder. Since this task also consists of some changes in the current architecture, it is especially important that this task is discussed on the ffmpeg-devel mailing list.	+	'''Description:''' MVC samples exist (somewhere? link!?), the codec is used on Bluray media, FFmpeg is missing a decoder. Since this task also consists of some changes in the current architecture, it is especially important that this task is discussed on the ffmpeg-devel mailing list.
	As qualification you have to do some work that demonstrates your understanding of MVC and that is a subpart of the whole MVC implementation.		As qualification you have to do some work that demonstrates your understanding of MVC and that is a subpart of the whole MVC implementation.

FFmpeg Summer of Code 2013

2013-02-22T12:01:27Z

Revision as of 12:01, 22 February 2013		Current revision
Line 1:		Line 1:
	FFmpeg Summer of Code Ideas List		FFmpeg Summer of Code Ideas List

-	== Proposing Ideas ==	+	= Proposing Ideas =
		+
	If you have a project idea please contact a developer first at the #ffmpeg-devel IRC channel on Freenode or via the [http://ffmpeg.org/contact.html ffmpeg-devel mailing list]. A good source of ideas is the [https://ffmpeg.org/trac/ffmpeg/ FFmpeg bug tracker] and [[FFmpeg_Summer_of_Code_2012\|FFmpeg Summer of Code 2012 Ideas List]].		If you have a project idea please contact a developer first at the #ffmpeg-devel IRC channel on Freenode or via the [http://ffmpeg.org/contact.html ffmpeg-devel mailing list]. A good source of ideas is the [https://ffmpeg.org/trac/ffmpeg/ FFmpeg bug tracker] and [[FFmpeg_Summer_of_Code_2012\|FFmpeg Summer of Code 2012 Ideas List]].

	When adding an idea follow this template for consistency:		When adding an idea follow this template for consistency:

-	=== Example Title ===	+	== Example Title ==
		+
	'''Description:''' A few sentences or a short paragraph describing the task.		'''Description:''' A few sentences or a short paragraph describing the task.

Line 15:		Line 17:
	'''Mentor:''' List mentor and backup mentor if there is one and contact info such as IRC name or email address.		'''Mentor:''' List mentor and backup mentor if there is one and contact info such as IRC name or email address.

-	== GSoC Ideas ==	+	= GSoC Ideas =

-	=== Audio codecs ===	+	== Audio codecs ==
		+
		+	=== AAC ===

-	==== AAC ====
	'''Description:''' FFmpeg contains an AAC encoder and decoder, both of them can be improved in various ways. This is enough work for more than one GSoC project, so one part of your submission would be to define on which task exactly you want to work.		'''Description:''' FFmpeg contains an AAC encoder and decoder, both of them can be improved in various ways. This is enough work for more than one GSoC project, so one part of your submission would be to define on which task exactly you want to work.
	* AAC LD decoder		* AAC LD decoder
Line 28:		Line 31:
	See also the FFmpeg bug tracker for AAC issues, fixing one of them or rebasing the existing incomplete BSAC decoder for current git head fixing one or more existing bugs are possible qualification tasks.		See also the FFmpeg bug tracker for AAC issues, fixing one of them or rebasing the existing incomplete BSAC decoder for current git head fixing one or more existing bugs are possible qualification tasks.

-	==== DTS / DCA ====	+	=== DTS / DCA ===
		+
	'''Description:''' FFmpeg contains a DTS decoder and an experimental DTS encoder. Both are missing some features.		'''Description:''' FFmpeg contains a DTS decoder and an experimental DTS encoder. Both are missing some features.
-	* DTS-HD decoder: A possible qualification task is to implement ticket #1920	+	* DTS-HD decoder improvements: A possible qualification task is to implement ticket #1920
	** Add support for mixed Core + DTS-HD stream structure		** Add support for mixed Core + DTS-HD stream structure
	** Add support for X96 extension (96khz)		** Add support for X96 extension (96khz)
	** Add support for XLL extension (lossless)		** Add support for XLL extension (lossless)
	** Add support for pure DTS-HD streams that do not contain a DTS core		** Add support for pure DTS-HD streams that do not contain a DTS core
		+	** Add support for multiple assets
		+	** Add support for LBR extension
	* DTS encoder improvements		* DTS encoder improvements

-	==== MPEG-4 ALS encoder ====	+	=== MPEG-4 ALS encoder ===
		+
	'''Description:''' An ALS decoder was implemented several years ago, an encoder is still missing.		'''Description:''' An ALS decoder was implemented several years ago, an encoder is still missing.

-	==== TrueHD encoder ====	+	=== TrueHD encoder ===
		+
	'''Description:''' FFmpeg currently does not support encoding to one of the lossless audio formats used on Bluray discs. This task consists of implementing a TrueHD encoder that allows to losslessly encode audio to play it on hardware devices capable of TrueHD decoding.		'''Description:''' FFmpeg currently does not support encoding to one of the lossless audio formats used on Bluray discs. This task consists of implementing a TrueHD encoder that allows to losslessly encode audio to play it on hardware devices capable of TrueHD decoding.

-	==== Opus decoder ====	+	=== Opus decoder ===
		+
	'''Description:''' Opus decoding is currently supported through the external libopus library		'''Description:''' Opus decoding is currently supported through the external libopus library
	* Write a native decoder, continue working on the existing unfinished implementation		* Write a native decoder, continue working on the existing unfinished implementation
	A possible qualification task is to port the existing incomplete decoder to current git head and improve it to show that you are capable of working on this task.		A possible qualification task is to port the existing incomplete decoder to current git head and improve it to show that you are capable of working on this task.

-	=== Video codecs ===	+	== Video codecs ==
		+
		+	=== HEVC / H265 ===

-	==== HEVC / H265 ====
	'''Description:''' The specification was finished, FFmpeg needs a decoder for this new format.		'''Description:''' The specification was finished, FFmpeg needs a decoder for this new format.
	* Write a basic decoder supporting I, P, and, only if time permits, B slices.		* Write a basic decoder supporting I, P, and, only if time permits, B slices.
Line 56:		Line 66:
	As a qualification task you need to implement parsing headers and maybe a bit beyond that to demonstrate that you are qualified and understand the HEVC specification. This project requires a solid understanding of video coding and C, it's not something for the average SOC student.		As a qualification task you need to implement parsing headers and maybe a bit beyond that to demonstrate that you are qualified and understand the HEVC specification. This project requires a solid understanding of video coding and C, it's not something for the average SOC student.

-	==== H264 MVC ====	+	=== H264 MVC ===
		+
	'''Description:''' MVC samples exist, the codec is used on Bluray media, FFmpeg is missing a decoder. Since this task also consists of some changes in the current architecture, it is especially important that this task is discussed on the ffmpeg-devel mailing list.		'''Description:''' MVC samples exist, the codec is used on Bluray media, FFmpeg is missing a decoder. Since this task also consists of some changes in the current architecture, it is especially important that this task is discussed on the ffmpeg-devel mailing list.
	As qualification you have to do some work that demonstrates your understanding of MVC and that is a subpart of the whole MVC implementation.		As qualification you have to do some work that demonstrates your understanding of MVC and that is a subpart of the whole MVC implementation.

-	==== VC-1 interlaced ====	+	=== VC-1 interlaced ===
		+
	'''Description:''' The FFmpeg VC-1 decoder has improved over the years, but many samples are still not decoded bit-exact and real-world interlaced streams typically show artefacts.		'''Description:''' The FFmpeg VC-1 decoder has improved over the years, but many samples are still not decoded bit-exact and real-world interlaced streams typically show artefacts.
	* Implement missing interlace features		* Implement missing interlace features
Line 66:		Line 78:
	As a qualification task, you should try to find a bug in the current decoder implementation and fix it.		As a qualification task, you should try to find a bug in the current decoder implementation and fix it.

-	==== animated png ====	+	=== Animated Portable Network Graphics (APNG) ===
		+
	'''Description:''' FFmpeg currently does not support Animated PNGs.		'''Description:''' FFmpeg currently does not support Animated PNGs.
-	* animated png decoder
-	* animated png encoder

-	==== JPEG 2000 ====	+	'''Specification:''' https://wiki.mozilla.org/APNG_Specification
		+
		+	'''Expected results:'''
		+	* APNG demuxer
		+	** implement robust probing, so that normal PNG images are not misdetected as APNG animations
		+	** splits stream into sensible packets (so they can be easily reused in APNG muxer)
		+	** survives fuzzing (zzuf)
		+	** add FATE coverage, coverage should be at least 70%
		+	** test code under valgrind so not invalid reads/writes happen
		+
		+	* APNG decoder
		+	** use existing PNG decoder code (write decoder in same file)
		+	** implement parsing of all APNG chunks (acTL, fcTL, fdAT)
		+	** error handling
		+	** survives fuzzing (zzuf)
		+	** add test for FATE, coverage should be at least 75%
		+	** CRC checksum validation
		+	** test code under valgrind so not invalid reads/writes happen
		+
		+	* APNG muxer && APNG encoder
		+	** write compliant files, make sure they play correctly in major web browsers that support APNG
		+
		+	'''Mentor: [[User:Pbm\|Paul B Mahol]]'''
		+
		+	'''Prerequisites:''' C coding skills, familiarity with git/source code control systems.
		+
		+	=== JPEG 2000 ===
		+
	'''Description:''' FFmpeg contains an experimental native JPEG 2000 encoder and decoder. Both are missing many features, see also the FFmpeg bug tracker for some unsupported samples.		'''Description:''' FFmpeg contains an experimental native JPEG 2000 encoder and decoder. Both are missing many features, see also the FFmpeg bug tracker for some unsupported samples.
	Work on an issue as a qualification task to show that you are capable of improving the codec implementation.		Work on an issue as a qualification task to show that you are capable of improving the codec implementation.

-	==== VP7 ====	+	=== VP7 ===
		+
	'''Description:''' Not many VP7 samples are in the wild, but no open-source decoder exists although Google has released a specification. Write a decoder that reuses as much as possible of existing FFmpeg code, it is likely that functions of the existing decoders for On2-based formats will be useful.		'''Description:''' Not many VP7 samples are in the wild, but no open-source decoder exists although Google has released a specification. Write a decoder that reuses as much as possible of existing FFmpeg code, it is likely that functions of the existing decoders for On2-based formats will be useful.

Line 81:		Line 120:

	==== glplay ====		==== glplay ====
		+
	'''Description:''' The SDL library that is used by FFplay has some deficiencies, adding OpenGL output to FFplay should allow for better performance (and less bugs at least for some hardware / driver combinations). This could be a new application (glplay), but it is probably simpler to extend ffplay to use OpenGL. You can use code from MPlayer's OpenGL vo module which may be relicensed under the LGPL.		'''Description:''' The SDL library that is used by FFplay has some deficiencies, adding OpenGL output to FFplay should allow for better performance (and less bugs at least for some hardware / driver combinations). This could be a new application (glplay), but it is probably simpler to extend ffplay to use OpenGL. You can use code from MPlayer's OpenGL vo module which may be relicensed under the LGPL.

FFmpeg Summer of Code 2013

2013-02-22T10:47:47Z

/* Video codecs */ vp7

Revision as of 10:47, 22 February 2013		Current revision
Line 70:		Line 70:
	* animated png decoder		* animated png decoder
	* animated png encoder		* animated png encoder
		+
		+	==== JPEG 2000 ====
		+	'''Description:''' FFmpeg contains an experimental native JPEG 2000 encoder and decoder. Both are missing many features, see also the FFmpeg bug tracker for some unsupported samples.
		+	Work on an issue as a qualification task to show that you are capable of improving the codec implementation.
		+
		+	==== VP7 ====
		+	'''Description:''' Not many VP7 samples are in the wild, but no open-source decoder exists although Google has released a specification. Write a decoder that reuses as much as possible of existing FFmpeg code, it is likely that functions of the existing decoders for On2-based formats will be useful.

	=== FFplay ===		=== FFplay ===

FFmpeg / Libav Summer Of Code

2013-02-22T10:35:20Z

Revision as of 10:35, 22 February 2013		Current revision
Line 1:		Line 1:
	The [[FFmpeg]] project has been a participant in the [http://code.google.com/soc/ Google Summer of Code] program since 2006. In 2011, the [[Libav]] fork became part of the same Summer of Code effort.		The [[FFmpeg]] project has been a participant in the [http://code.google.com/soc/ Google Summer of Code] program since 2006. In 2011, the [[Libav]] fork became part of the same Summer of Code effort.

		+	* [[FFmpeg_Summer_of_Code_2013\|2013 FFmpeg Project page]]
	* [[Libav Summer Of Code 2013\|2013 Libav project page]]		* [[Libav Summer Of Code 2013\|2013 Libav project page]]
	* [[Libav Summer Of Code 2012\|2012 Libav project page]]		* [[Libav Summer Of Code 2012\|2012 Libav project page]]

FFmpeg Summer of Code 2013

2013-02-22T10:27:20Z

/* Audio codecs */ Opus

Revision as of 10:27, 22 February 2013		Current revision
Line 16:		Line 16:

	== GSoC Ideas ==		== GSoC Ideas ==
		+
		+	=== Audio codecs ===
		+
		+	==== AAC ====
		+	'''Description:''' FFmpeg contains an AAC encoder and decoder, both of them can be improved in various ways. This is enough work for more than one GSoC project, so one part of your submission would be to define on which task exactly you want to work.
		+	* AAC LD decoder
		+	* AAC BSAC decoder: This has already been started, but the existing decoder still fails on many samples
		+	* AAC SSR decoder
		+	* AAC 960/120 MDCT window
		+	* AAC multi-channel encoding
		+	See also the FFmpeg bug tracker for AAC issues, fixing one of them or rebasing the existing incomplete BSAC decoder for current git head fixing one or more existing bugs are possible qualification tasks.
		+
		+	==== DTS / DCA ====
		+	'''Description:''' FFmpeg contains a DTS decoder and an experimental DTS encoder. Both are missing some features.
		+	* DTS-HD decoder: A possible qualification task is to implement ticket #1920
		+	** Add support for mixed Core + DTS-HD stream structure
		+	** Add support for X96 extension (96khz)
		+	** Add support for XLL extension (lossless)
		+	** Add support for pure DTS-HD streams that do not contain a DTS core
		+	* DTS encoder improvements
		+
		+	==== MPEG-4 ALS encoder ====
		+	'''Description:''' An ALS decoder was implemented several years ago, an encoder is still missing.
		+
		+	==== TrueHD encoder ====
		+	'''Description:''' FFmpeg currently does not support encoding to one of the lossless audio formats used on Bluray discs. This task consists of implementing a TrueHD encoder that allows to losslessly encode audio to play it on hardware devices capable of TrueHD decoding.
		+
		+	==== Opus decoder ====
		+	'''Description:''' Opus decoding is currently supported through the external libopus library
		+	* Write a native decoder, continue working on the existing unfinished implementation
		+	A possible qualification task is to port the existing incomplete decoder to current git head and improve it to show that you are capable of working on this task.
		+
		+	=== Video codecs ===
		+
		+	==== HEVC / H265 ====
		+	'''Description:''' The specification was finished, FFmpeg needs a decoder for this new format.
		+	* Write a basic decoder supporting I, P, and, only if time permits, B slices.
		+	* It does not need to be ASM/SIMD optimized but its high level structure must permit such optimizations to be easily added later.
		+	As a qualification task you need to implement parsing headers and maybe a bit beyond that to demonstrate that you are qualified and understand the HEVC specification. This project requires a solid understanding of video coding and C, it's not something for the average SOC student.
		+
		+	==== H264 MVC ====
		+	'''Description:''' MVC samples exist, the codec is used on Bluray media, FFmpeg is missing a decoder. Since this task also consists of some changes in the current architecture, it is especially important that this task is discussed on the ffmpeg-devel mailing list.
		+	As qualification you have to do some work that demonstrates your understanding of MVC and that is a subpart of the whole MVC implementation.
		+
		+	==== VC-1 interlaced ====
		+	'''Description:''' The FFmpeg VC-1 decoder has improved over the years, but many samples are still not decoded bit-exact and real-world interlaced streams typically show artefacts.
		+	* Implement missing interlace features
		+	* Make more reference samples bit-exact
		+	As a qualification task, you should try to find a bug in the current decoder implementation and fix it.
		+
		+	==== animated png ====
		+	'''Description:''' FFmpeg currently does not support Animated PNGs.
		+	* animated png decoder
		+	* animated png encoder
		+
		+	=== FFplay ===
		+
		+	==== glplay ====
		+	'''Description:''' The SDL library that is used by FFplay has some deficiencies, adding OpenGL output to FFplay should allow for better performance (and less bugs at least for some hardware / driver combinations). This could be a new application (glplay), but it is probably simpler to extend ffplay to use OpenGL. You can use code from MPlayer's OpenGL vo module which may be relicensed under the LGPL.

	=== Libavfilter extension ===		=== Libavfilter extension ===

Libav Summer Of Code 2013

2013-02-22T07:54:15Z

Remove the sws project, its mentor thinks it is pointless and a complete rewrite is needed instead.

Revision as of 07:54, 22 February 2013		Current revision
Line 190:		Line 190:

	''Mentor: [[User:lu_zero\|Luca Barbato]]''		''Mentor: [[User:lu_zero\|Luca Barbato]]''
-
-	=== Swscale Cleanup and Additions ===
-
-	Libswscale is an open source library for colourspace conversion. However, it requires significant cleanup to allow
-	it to support modern features. Knowledge of x86 assembly is preferred, though it can be learnt as part of GSOC.
-
-	* Support for more interleaved colourspaces. This is useful because interleaved chroma provides improved cache coherency and would form the basis for future optimisations in libav's decoders.
-	* Support for the vast number of packed pixel formats (e.g r210, v210). Many are currently implemented as decoders but it is agreed that all uses of such formats are effectively colourspace conversions, they should be included in swscale. This task will involve collaborating with the student of "Adobe DNG Decoder" (if applicable) to rewrite the pixel format headers to support more complex pixel formats.
-	* Inline asm to yasm conversion
-	* RGB work (todo: expand this)
-	* Bayer layouts
-	* Other general cleanup
-
-	''Mentor: Kieran Kunhya (kierank)''

	=== DTS-LBR decoder ===		=== DTS-LBR decoder ===

FFmpeg Summer of Code 2013

2013-02-22T06:17:26Z

add 2012 ideas list link

New page

FFmpeg Summer of Code Ideas List

== Proposing Ideas ==
If you have a project idea please contact a developer first at the #ffmpeg-devel IRC channel on Freenode or via the [http://ffmpeg.org/contact.html ffmpeg-devel mailing list]. A good source of ideas is the [https://ffmpeg.org/trac/ffmpeg/ FFmpeg bug tracker] and [[FFmpeg_Summer_of_Code_2012|FFmpeg Summer of Code 2012 Ideas List]].

When adding an idea follow this template for consistency:

=== Example Title ===
'''Description:''' A few sentences or a short paragraph describing the task.

'''Expected results:''' Bulleted list or paragraph describing what the student is expected to achieve.

'''Prerequisites:''' Skills or knowledge required by student.

'''Mentor:''' List mentor and backup mentor if there is one and contact info such as IRC name or email address.

== GSoC Ideas ==

=== Libavfilter extension ===

'''Description:''' Libavfilter is the FFmpeg filtering library that started as a 2007 SoC [[FFmpeg Summer Of Code#Video Filter API (AKA libavfilter)|project]]. It currently supports audio and video filtering and generation support.

* This work may focus on porting MPlayer filters which are currently integrated through the mp wrapper.
* For each port the student should verify that the new filter produces the same output and checking that the new integrated filter is not slower.
* For more ideas read the [[FFmpeg_/_Libav_Summer_Of_Code_2011#Libavfilter_video_work|GSoC 2011 libavfilter video proposal]] and [https://ffmpeg.org/trac/ffmpeg/query?status=new&status=open&status=reopened&component=avfilter&col=id&col=summary&col=status&col=type&col=priority&col=component&col=version&order=priority trac libavfilter tickets].

'''Expected results:''' Write or port audio and video filters and possibly fix/extend libavfilter API and design.

'''Prerequisites:''' C coding skills, familiarity with git/source code control systems. Some background on DSP and image/sound processing techniques would be a bonus but is not strictly required.

'''Mentor:''' Stefano Sabatini (''saste'' on IRC).

[[Category:FFmpeg]]

GoToMeeting Codec

2013-02-20T18:54:48Z

/* Image decoding */

Revision as of 18:54, 20 February 2013		Current revision
Line 170:		Line 170:

	==== Image decoding ====		==== Image decoding ====
		+
		+	Image decoding is context-dependent and always tries to check some flags and retrieve pixel value from cache instead of decoding it directly.
		+
		+	Overall decoding scheme:

	for (y = 0; y < height; y++) {		for (y = 0; y < height; y++) {
Line 175:		Line 179:
	while (x < width) {		while (x < width) {
	if (x > 1 && y > 0 &&		if (x > 1 && y > 0 &&
-	rgb[x - 1][y] != rgb[x - 2][y] &&	+	rgb[x - 1, y] != rgb[x - 2, y] &&
-	rgb[x - 1][y] != rgb[x ][y - 1] &&	+	rgb[x - 1, y] != rgb[x, y - 1] &&
-	rgb[x - 1][y] != rgb[x - 1][y - 1] &&	+	rgb[x - 1, y] != rgb[x - 1, y - 1] &&
-	rgb[x - 1][y] != rgb[x - 2][y - 1] &&	+	rgb[x - 1, y] != rgb[x - 2, y - 1] &&
-	pixel_in_cache(rgb[x - 1][y]) {	+	!pixel_in_cache(rgb[x - 1, y])) {
-	rgb[x][y] = decode_pixel_with_prediction(x, y);	+	rgb[x, y] = decode_pixel_with_prediction(x, y);
	x++;		x++;
	continue;		continue;
Line 187:		Line 191:
	if (run_length > 0) {		if (run_length > 0) {
	// pixel value may get changed here		// pixel value may get changed here
-	decode_modified_pix(x, y, run_length, &pix);	+	reuse_top_neighbours_if_possible(x, y, run_length, &pix);
-	while (run_length--)	+	while (run_length--) {
-	rgb[x++][y] = pix;	+	rgb[x, y] = pix;
-	} else if (decode_from_cache(&pix)) {	+	x++;
-	rgb[x][y] = pix;	+	}
		+	} else if (x > 0 && decode_from_list(rgb[x - 1, y], &pix)) {
		+	rgb[x, y] = pix;
	x++;		x++;
	} else {		} else {
-	rgb[x][y] = decode_pixel_with_prediction(x, y);	+	rgb[x, y] = decode_pixel_with_prediction(x, y);
		+	if (x)
		+	add_to_list(pixel_list[rgb[x - 1, y]], rgb[x, y]);
	x++;		x++;
	}		}
	}		}
	}		}
		+
		+	Run decoding:
		+
		+	run_length = 0;
		+
		+	if (x > 1 && x < width - 1 && y > 1) {
		+	L = rgb[x - 1, y];
		+	LL = rgb[x - 2, y];
		+	TR = rgb[x + 1, y - 1];
		+	T = rgb[x, y - 1];
		+	TL = rgb[x - 1, y - 1];
		+	TLL = rgb[x - 2, y - 1];
		+	TTR = rgb[x + 1, y - 2];
		+	TT = rgb[x, y - 2];
		+	TTL = rgb[x - 1, y - 2];
		+
		+	if (x != ctx->last_run_end) {
		+	idx = (TTL != TL) << 0\|
		+	(TT != T) << 1 \|
		+	(TTR != TR) << 2 \|
		+	(TLL != TL) << 3 \|
		+	(TL != T) << 4 \|
		+	(TR != T) << 5 \|
		+	(TL != L) << 6 \|
		+	(LL != L) << 7;
		+	flag = els_decode_bit(ctx->left_context[idx]);
		+	} else {
		+	flag = 1;
		+	}
		+	if (flag)
		+	add_to_cache(L);
		+	else
		+	pixel_val = L;
		+	for (;;) {
		+	if (flag) {
		+	// not perfect
		+	idx = (TTL != TL) << 0\|
		+	(TT != T) << 1 \|
		+	(TTR != TR) << 2 \|
		+	(TLL != TL) << 3 \|
		+	(TL != T) << 4 \|
		+	(TR != T) << 5 \|
		+	(TL != L) << 6 \|
		+	(LL != L) << 7;
		+	if (els_decode_bit(ctx->top_context[idx])) {
		+	pixel_val = T;
		+	flag2 = 0;
		+	} else {
		+	if (!pixel_in_cache(T))
		+	add_to_cache(T);
		+	flag2 = 1;
		+	}
		+	} else {
		+	flag2 = (pixel_val != T);
		+	}
		+	x++;
		+	if (x >= width - 1)
		+	break;
		+	update L, LL, LR, T, TL, TLL, TTR, TT and TTL;
		+	if (!flag2 && TL == T && T == TR) {
		+	if (!decode_run_length(&x))
		+	break;
		+	update L, LL, LR, T, TL, TLL, TTR, TT and TTL;
		+	}
		+	idx = (TTL != TL) << 0\|
		+	(TT != T) << 1 \|
		+	(TTR != TR) << 2 \|
		+	(TLL != TL) << 3 \|
		+	(TL != T) << 4 \|
		+	(TR != T) << 5 \|
		+	(TL != L) << 6 \|
		+	(LL != L) << 7;
		+	if (els_decode_bit(ctx->left_context[idx]))
		+	break;
		+	}
		+	ctx->last_run_end = x;
		+	run_length = x - old_x;
		+	return !flag;
		+	}
		+	if (x > 0) {
		+	if (!els_decode_bit(ctx->left_flag_ctx)) {
		+	pixel_val = rgb[x - 1, y];
		+	run_length = 1;
		+	} else {
		+	add_to_cache(rgb[x - 1, y]);
		+	}
		+	}
		+	if (y > 0) {
		+	top_pix = rgb[x, y - 1];
		+	if (empty_pixel_cache() \|\| first_pixel_in_cache() != top_pix) {
		+	if (!els_decode_bit(ctx->top_flag_ctx)) {
		+	pixel_val = top_pix;
		+	run_length = 1;
		+	} else {
		+	add_to_cache(top_pix);
		+	}
		+	}
		+	}
		+
		+	Decoding run length (essentially the run on the above line is used as a reference and is either returned immediately or a value not greater than it is decoded):
		+
		+	pos_R = x + 1;
		+	pos_RR = x + 2;
		+	while (pos_RR < width && rgb[pos_RR, y - 1] == rgb[pos_R, y]) {
		+	pos_R++;
		+	pos_RR++;
		+	}
		+	bits = log2_int(pos_R - x);
		+	if (els_decode_bit(ctx->dist_context[bits]))
		+	return pos_R - x;
		+	flag = 0;
		+	bit = 1 << (bits - 1);
		+	mask = 0;
		+	run_length = 0;
		+	while (bits >= 0) {
		+	if (((run_length & mask) \| bit) < pos_R - x) {
		+	if (els_decode_bit(flag ? ctx->one_context : ctx->length_context[bits])) {
		+	flag = 1;
		+	run_length \|= 1 << bits;
		+	}
		+	}
		+	mask \|= bit;
		+	bit >>= 1;
		+	bits--;
		+	}
		+
		+	Reuse neighbours if possible:
		+
		+	if (x > 0 && y > 0) {
		+	TL = rgb[x - 1, y - 1];
		+	L = rgb[x - 1, y];
		+	T = rgb[x, y - 1];
		+	if (TL != L && TL != T && !pixel_is_in_cache(TL)) {
		+	if (els_decode_bit(ctx->TL_context[TL])) {
		+	modify current pixel value to be TL
		+	return
		+	}
		+	add_to_cache(TL);
		+	}
		+	}
		+	if (x + run_size < width - 1 && y > 0) {
		+	TR = rgb[x + 1, y - 1];
		+	T = rgb[x, y - 1];
		+	if (T != TR && !pixel_is_in_cache(TR)) {
		+	if (els_decode_bit(ctx->TR_context[TR])) {
		+	modify current pixel value to be TR
		+	return
		+	}
		+	add_to_cache(TR);
		+	}
		+	}
		+
		+	Decoding from list:
		+
		+	list = get_list_for_pixel(rgb[x - 1, y]);
		+	while (list) {
		+	if (!pixel_is_in_cache(list->pix_val)) {
		+	if (els_decode_bit(list->rung)) {
		+	output_pixel_value = list->pix_val;
		+	remove current entry from the list;
		+	return success;
		+	}
		+	add_to_cache(list->pix_val);
		+	}
		+	list = list->next;
		+	}
		+	return fail;

	=== Compression method 2 (ELS image + JPEG) ===		=== Compression method 2 (ELS image + JPEG) ===

Cinepak

2013-02-19T09:00:15Z

refreshed info, added a technical note

Revision as of 09:00, 19 February 2013		Current revision
Line 5:		Line 5:
	* Windows binary codec: [http://www.probo.com/cinepak.htm http://www.probo.com/cinepak.htm]		* Windows binary codec: [http://www.probo.com/cinepak.htm http://www.probo.com/cinepak.htm]

-	The Cinepak coding method is a vector quantization scheme with interframe update optimization. It is known to operate most commonly using a modified YUV 4:2:0 colorspace but also supports 256-grayscale mode. A modified variant of this format is used for full motion video on many Sega Saturn games (in [[Sega FILM]] files often bearing the .cpk extension). It is not known if this format has anything in common with the [[Cinepak For Sega]] format used in many Sega CD games.	+	The Cinepak coding method is a vector quantization scheme with interframe update optimization. It is known to operate most commonly using a modified YUV 4:2:0 colorspace but also supports 256-grayscale and palettized mode. A modified variant of this format is used for full motion video on many Sega Saturn games (in [[Sega FILM]] files often bearing the .cpk extension). It is not known if this format has anything in common with the [[Cinepak For Sega]] format used in many Sega CD games.
-		+
-	ffmpeg contains an almost compliant decoder (using YUV420 instead of the Cinepak colorspace, which distorts colors somewhat - should be easy to fix).	+

	There are several versions of a binary proprietary encoder/decoder as a windows dll, among others ftp://ftp.probo.com/pub/cinepak/cvid32.zip		There are several versions of a binary proprietary encoder/decoder as a windows dll, among others ftp://ftp.probo.com/pub/cinepak/cvid32.zip
Line 14:		Line 12:
	http://titan.codemill.se/~tomhar/cinepakenc.patch		http://titan.codemill.se/~tomhar/cinepakenc.patch

-	Unfortunately the open source decoder present in ffmpeg is using the non-compliant YUV420 colorspace instead of the native Cinepak one (for the fix see below).	+	The encoder mentioned above was adapted for the current (December 2012) ffmpeg, bugfixed and improved for better rate/distortion performance by Rl. The compression speed is barely optimized (it is slow), a choice made for keeping simplicity and r/d. A snapshot 2013-02-18 is at
-		+
-	The encoder mentioned above was adapted for the current (December 2012) ffmpeg, bugfixed and improved for better rate/distortion performance by Rl. The compression speed is barely optimized (it is slow), for simplicity and better r/d. A snapshot 2013-02-12 is at	+
	http://www.aetey.se/dl/cinepak-encoder-ffmpeg.patch		http://www.aetey.se/dl/cinepak-encoder-ffmpeg.patch

-	There is also a patch introducing the correct colorspace for the open source decoder	+	ffmpeg used to contain an almost compliant decoder (using YUV420 instead of the Cinepak colorspace, which distorts colors), a colorspace fix has been submitted (as of 2013-02-18) by Rl, also improving decoding speed with 15-60% and stream format compliance.This patch is also available at
	http://www.aetey.se/dl/cinepak-decoder-colorspace.patch		http://www.aetey.se/dl/cinepak-decoder-colorspace.patch

	The encoder was never submitted for inclusion in ffmpeg, feel free to push it upstream.		The encoder was never submitted for inclusion in ffmpeg, feel free to push it upstream.
		+
		+	----
		+	A technical note: x1, x2 and y1, y2 strip coordinates are absolute, unless y1==0 and the strip is not the first one on the frame - then y1 is assumed to coincide with y2 from the previous strip and the read y2 contains the strip height, i.e. ''if(read_y1==0){ y1 = previous_y2; y2 = previous_y2 + read_y2; }''
		+	----

	[[Category:Video Codecs]]		[[Category:Video Codecs]]

GoToMeeting Codec

2013-02-18T20:06:21Z

(Difference between revisions)

Libav Summer Of Code 2013

2013-02-18T17:09:46Z

Remove the HEVC decoder task, the original author i still working on it, but will not participate in gsoc.

Revision as of 17:09, 18 February 2013		Current revision
Line 92:		Line 92:

	''Mentor: Daniel Kang'' (Jumpyshoes on #libav-devel@chat.freenode.net; daniel.d.kang@gmail.com -- ping me on IRC and email me).		''Mentor: Daniel Kang'' (Jumpyshoes on #libav-devel@chat.freenode.net; daniel.d.kang@gmail.com -- ping me on IRC and email me).
-
-	=== HEVC/H265 decoder ===
-
-	* HEVC is the next-generation video standard from the MPEG standards committee. Your job is to write a decoder that can playback HEVC files.
-	* It does not need to be SIMD-optimized, but preferably has relevant functions separated in DSP contexts so they're easy to optimize later on.
-	* This task will depend on the current standardisation status of HEVC. Final publication is in 2013 but there may be parts which will not change much anyway.
-	* Draft spec: http://www.itscj.ipsj.or.jp/sc29/open/29view/29n12612c.htm
-	* HM (draft reference decoder) git mirror: http://hevc.kw.bbc.co.uk/git/w/jctvc-hm.git
-
-	Note that this is a difficult project. Do not try to apply unless you already have experience with H.264 as well as reading and writing complex C code.
-
-	''Mentor: [[User:Ronald_S._Bultje\|Ronald S. Bultje]]''

	=== DTS-HD decoder ===		=== DTS-HD decoder ===

Otrkey

2013-02-14T02:17:28Z

New page

* Website: http://www.onlinetvrecorder.com/
* Samples: http://otr.datenkeller.at/ http://otr.dwolp.de/
* (public domain?) Decoder: http://pyropeter.github.com/otrtool/

.otrkey files are encrypted video files from the onlinetvrecorder website.
the files are publically available, but require a key to decrypt them.

similar to wmv drm, it stores a key inside the file and requires a second key from the website.

A gpu brute force cracker may be able to decrypt such files.

Libav Summer Of Code 2013

2013-02-14T02:05:29Z

Add last year's unfinished projects as ideas.

Revision as of 02:05, 14 February 2013		Current revision
Line 67:		Line 67:

	'''Mentor: [[User:elenril\|Anton Khirnov]]		'''Mentor: [[User:elenril\|Anton Khirnov]]
		+
		+	=== spin off build system into a separate project ===
		+
		+	Our build system is neat enough to make into a more general solution to be reused by other projects.
		+
		+	The goal of this project is to achieve exactly that. Intermediate steps will be reading, understanding and documenting the current build system, refactoring parts that can be generalized further and finally making a prototype implementation for libpostproc.
		+
		+	You will require skills in POSIX shell, GNU Make and a firm command of English.
		+
		+	''Mentor: [[User:DonDiego\|Diego Biurrun]]''
		+
		+
		+	== 2nd Tier Project Proposals ==
		+
		+	None of these are confirmed yet, just added here as ideas.
		+
		+	=== Assembly Unit Testing Framework ===
		+	* Libav has a lot of assembly and not enough tests for it. Your job is to write a unit testing framework for assembly.
		+	* The framework should work across all supported architectures and operating systems.
		+	* The framework should measure exactly how fast an individual function is (e.g. using START/STOP_TIMER).
		+	* The framework should be able to test functions in isolation.
		+	* x264's checkasm can be used as a reference.
		+	* The qualification task will be to implement at least one unit test and have an idea of how to do the rest.
		+
		+	''Mentor: Daniel Kang'' (Jumpyshoes on #libav-devel@chat.freenode.net; daniel.d.kang@gmail.com -- ping me on IRC and email me).
		+
		+	=== HEVC/H265 decoder ===
		+
		+	* HEVC is the next-generation video standard from the MPEG standards committee. Your job is to write a decoder that can playback HEVC files.
		+	* It does not need to be SIMD-optimized, but preferably has relevant functions separated in DSP contexts so they're easy to optimize later on.
		+	* This task will depend on the current standardisation status of HEVC. Final publication is in 2013 but there may be parts which will not change much anyway.
		+	* Draft spec: http://www.itscj.ipsj.or.jp/sc29/open/29view/29n12612c.htm
		+	* HM (draft reference decoder) git mirror: http://hevc.kw.bbc.co.uk/git/w/jctvc-hm.git
		+
		+	Note that this is a difficult project. Do not try to apply unless you already have experience with H.264 as well as reading and writing complex C code.
		+
		+	''Mentor: [[User:Ronald_S._Bultje\|Ronald S. Bultje]]''
		+
		+	=== DTS-HD decoder ===
		+
		+	* ETSI released specifcations (http://www.etsi.org/deliver/etsi_ts/102100_102199/102114/01.03.01_60/ts_102114v010301p.pdf). Your job is to complete the existing decoder with the following features.
		+
		+	(1) Add support for mixed Core + DTS-HD stream structure
		+	(DtsCoreFrame+DtsHdFrame+DtsCoreFrame+DtsHdFrame+...), used by Blu-Ray main
		+	and commentary tracks.
		+	(2) Add support for XXCh extension (6.1 and 7.1 channels).
		+	(3) Add support for X96 extension (96khz).
		+	(4) Add support for XLL extension (lossless).
		+	(5) Add support for a pure DTS-HD stream structure
		+	(DtsHdFrame+DtsHdFrame+DtsHdFrame+...), used by Blu-Ray PiP tracks.
		+	(6) Add support for XBR extension (extra bitrate).
		+
		+
		+	''Mentor: Benjamin Larsson''
		+
		+	=== MPEG-4 ALS Roundup ===
		+
		+	This task is to update and enhance the existing ALS decoder as well as integrate
		+	and enhance the rudimentary encoder found at:
		+	https://github.com/justinruggles/FFmpeg-alsenc
		+
		+	Possible features are:
		+
		+	* implement rls-lms in the decoder
		+	* do correct channel layout/sort handling in the decoder
		+	* update to current master
		+	* use codec private options
		+	* implement encode2(), setting pts and duration
		+	* document options and examples in encoders.texi
		+	* come up with a good set of encoding tests for FATE
		+	* implement mcc/channel sort in the encoder
		+	* implement rls-lms in the encoder
		+	* implement float support
		+
		+	''Mentor: [[User:Jruggle\|Justin Ruggles]]''
		+
		+
		+	=== Opus Decoder ===
		+
		+	Implement an independent Opus decoder using the publicly-available specification at:
		+	http://tools.ietf.org/html/draft-ietf-codec-opus-11
		+
		+	* The reference source code should only be used as a normative document reference when required (i.e. this should not just be a port of libopus)
		+	* Fully support Ogg/Opus mapping: https://wiki.xiph.org/OggOpus
		+	* Handle CELT, SILK, and Hybrid modes (including transitions)
		+	* (optional) Handle more than 2 channels
		+
		+	''Mentor: [[User:Jruggle\|Justin Ruggles]]''
		+
		+
		+	=== Adobe DNG Decoder (Basic Support) ===
		+
		+	Adobe Digital Negative (DNG) is an attempt at a universal file format for raw camera images. Most camera manufacturers have their own proprietary raw image format. Adobe provides tools for converting these to DNG with minimal or no loss of information for more reliable long-term support in a format with an open specification.
		+
		+	The project goal would be to add features required for basic support of DNG files. Some of these include:
		+	* test/improve TIFF and LJPEG 16-bit decoding support
		+	* implement both variants of JPEG-in-TIFF in the TIFF decoder
		+	* add basic handling for Bayer CFA pixel format(s), including demosaicing
		+	* conversion from camera colorspace to RGB
		+	* export of DNG/TIFF/Exif metadata
		+
		+	Resources:
		+	* [http://en.wikipedia.org/wiki/Digital_Negative Wikipedia Article]
		+	* [http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/products/photoshop/pdfs/dng_spec.pdf Specification]
		+	* DNG samples can be created from other raw formats using the free [http://www.adobe.com/products/photoshop/extend.displayTab2.html DNG Converter] program
		+	* A good place to find raw camera samples is http://www.imaging-resource.com
		+
		+	''Mentor: [[User:Jruggle\|Justin Ruggles]]''
		+
		+
		+	=== On2 VP7 decoder ===
		+
		+	VP7 is a DCT-based video codec. At the moment, it seems to lack a reference implementation, but we do have a spec and may take hint from libavcodec's VP8 and VP6 decoder and libvpx. MPlayer can decode VP7 by loading a binary. To begin working on the project, one has to setup a reference decoder against which to compare our output. This can be done by either writing a wrapper for the binary or (maybe) hacking libvpx itself.
		+
		+	You might want to discuss with us how and where to start. Drop by on IRC if you need help. It is not as difficult as it sounds.
		+
		+	* [http://multimedia.cx/mirror/VP7_Data_Format_and_Decoder_Overview.pdf Specification]
		+	* [http://samples.libav.org/V-codecs/VP7/ Samples]
		+
		+	''Mentor: [[User:Shahriman\|Mashiat Sarker Shakkhar]]''
		+
		+	=== Rewrite avserver ===
		+
		+	Libav needs a better system to serve streams, the current codebase had a number of design defect showing its age. The new avserver should be written from scratch, leveraging the knowledge piled up.
		+
		+	The implementation will be incrementally complex and possibly modular.
		+
		+	* Implement support to rtsp record/announce
		+	* Expose RTMP and RTSP specific API (so the server won't have to use private calls)
		+	* Write a simple rtsp, http, rtmp redirector (listen for publish/announce and rebroadcast the received streams)
		+	* Add the capability to serve on-demand content reading from a single path
		+
		+	Ideally the first implementation can be made using a poll/event loop and then moved to use threads.
		+
		+	''Mentor: [[User:lu_zero\|Luca Barbato]]''
		+
		+	=== Swscale Cleanup and Additions ===
		+
		+	Libswscale is an open source library for colourspace conversion. However, it requires significant cleanup to allow
		+	it to support modern features. Knowledge of x86 assembly is preferred, though it can be learnt as part of GSOC.
		+
		+	* Support for more interleaved colourspaces. This is useful because interleaved chroma provides improved cache coherency and would form the basis for future optimisations in libav's decoders.
		+	* Support for the vast number of packed pixel formats (e.g r210, v210). Many are currently implemented as decoders but it is agreed that all uses of such formats are effectively colourspace conversions, they should be included in swscale. This task will involve collaborating with the student of "Adobe DNG Decoder" (if applicable) to rewrite the pixel format headers to support more complex pixel formats.
		+	* Inline asm to yasm conversion
		+	* RGB work (todo: expand this)
		+	* Bayer layouts
		+	* Other general cleanup
		+
		+	''Mentor: Kieran Kunhya (kierank)''
		+
		+	=== DTS-LBR decoder ===
		+
		+	This is the DTS equivalent to E-AC3 but not technically related to DTS/DTS-HD. It is found in the following specification: http://www.etsi.org/deliver/etsi_ts/102100_102199/102114/01.03.01_60/ts_102114v010301p.pdf). The task is to find a way of making the official
		+	decoder decode just the LBR stream (and not mix it into the main audio) and use that to verify decoder compliance of the decoder you wrote.
		+	The spec may be incomplete or require parts to be reverse engineered from the binary.
		+
		+	''Mentor: ???''
		+
		+	[[Category:Libav]]

FFmpeg / Libav Summer Of Code

2013-02-14T02:02:28Z

re-add ffmpeg link which diego removed for some reason.

Revision as of 02:02, 14 February 2013		Current revision
Line 3:		Line 3:
	* [[Libav Summer Of Code 2013\|2013 Libav project page]]		* [[Libav Summer Of Code 2013\|2013 Libav project page]]
	* [[Libav Summer Of Code 2012\|2012 Libav project page]]		* [[Libav Summer Of Code 2012\|2012 Libav project page]]
		+	* [[FFmpeg_Summer_of_Code_2012\|2012 FFmpeg Project page]]
	* [[FFmpeg / Libav Summer Of Code 2011\|2011 project page]]		* [[FFmpeg / Libav Summer Of Code 2011\|2011 project page]]
	* [[FFmpeg Summer Of Code 2010\|2010 project page]]		* [[FFmpeg Summer Of Code 2010\|2010 project page]]

Libav Summer Of Code 2012

2013-02-13T23:17:42Z

fix category

Revision as of 23:17, 13 February 2013		Current revision
Line 201:		Line 201:


-	[[Category:FFmpeg]]	+	[[Category:Libav]]

FFmpeg / Libav Summer Of Code

2013-02-13T22:46:38Z

Add link to 2013 SoC page.

Revision as of 22:46, 13 February 2013		Current revision
Line 1:		Line 1:
	The [[FFmpeg]] project has been a participant in the [http://code.google.com/soc/ Google Summer of Code] program since 2006. In 2011, the [[Libav]] fork became part of the same Summer of Code effort.		The [[FFmpeg]] project has been a participant in the [http://code.google.com/soc/ Google Summer of Code] program since 2006. In 2011, the [[Libav]] fork became part of the same Summer of Code effort.

-	* [[FFmpeg_Summer_of_Code_2012\|2012 FFmpeg Project page]]	+	* [[Libav Summer Of Code 2013\|2013 Libav project page]]
	* [[Libav Summer Of Code 2012\|2012 Libav project page]]		* [[Libav Summer Of Code 2012\|2012 Libav project page]]
	* [[FFmpeg / Libav Summer Of Code 2011\|2011 project page]]		* [[FFmpeg / Libav Summer Of Code 2011\|2011 project page]]

Libav Summer Of Code 2013

2013-02-13T22:43:31Z

minor wording fixes

Revision as of 22:43, 13 February 2013		Current revision
Line 1:		Line 1:
	== How it works ==		== How it works ==

-	Google's Summer of Code program is simple: you (the student) work on a project, full-time, during the whole summer, and you get assistance (advice, mentoring) from a seasoned Libav developer who knows his way around the project and has considerable standing in the community. By doing so, you'll learn to operate in an opensource project, you'll get relevant coding experience, and you'll have a chance at earning money while doing fun stuff during the summer. So, you need a project, a mentor, do a qualification task (see below) so we can quickly assess how good a candidate we feel you'll be for the program, and then you can apply.	+	Google's Summer of Code program is simple: you (the student) work on a project, full-time, during the whole summer, and you get assistance (advice, mentoring) from a seasoned Libav developer who knows the project and has considerable standing in the community. By doing so, you'll learn to operate in an open source project, you'll get relevant coding experience, and you'll have a chance at earning money while doing fun stuff during the summer. So, you need a project, a mentor, a qualification task (see below) so we can quickly assess how good a candidate we feel you'll be for the program, and then you can apply.

	=== Selecting a project ===		=== Selecting a project ===
Line 10:		Line 10:

	=== Contacting developers/mentors ===		=== Contacting developers/mentors ===
-	Once you've found a project (with or without mentor), start talking to the developers of the Libav project. We can often be found on IRC, and you can talk to us on mailinglists also. Hop on irc.freenode.net channel #libav-devel, or talk to us on libav-devel@libav.org. Here, you'll be able to ask around for mentors for projects without a mentor if you need to. If you're trying to define your own project, explain (with reasonable amount of detail) what you intend to achieve and why you think your project should be in our Summer of Code program. Once you've found a mentor, you're good to start your qualification task.	+	Once you've found a project (with or without mentor), start talking to the developers of the Libav project. We can often be found on IRC, and you can talk to us on the mailing lists as well. Hop on irc.freenode.net, channel #libav-devel, or mail us at libav-devel@libav.org. There, you'll be able to ask around for persons to guide you on projects without a mentor if you need to. If you're trying to define your own project, explain (with reasonable amount of detail) what you intend to achieve and why you think your project should be in our Summer of Code program. Once you've found a mentor, you're good to start your qualification task.

	Note that the self-selected mentor needs to have considerable standing in the community to be eligible for mentoring. Likewise, if you choose to define your own Summer of Code project, some community members of considerable standing need to vouch for your project.		Note that the self-selected mentor needs to have considerable standing in the community to be eligible for mentoring. Likewise, if you choose to define your own Summer of Code project, some community members of considerable standing need to vouch for your project.
Line 17:		Line 17:
	The goal of a qualification task is to see if the mentor and student feel that, together, they will be able to finish the project of their choice. More specifically, the mentor will want to test whether the student has the skills and work ethics to complete a large coding project in a limited amount of time. The student will want to make sure that the mentor provides (useful) assistance when necessary. Therefore, students should select a mentor and a Summer of Code project before starting their work on a qualification task. The qualification task is often (but not necessarily) related to the selected project. For example, if your project will be to reverse engineer a new video codec, the qualification task may be to write a partial bitstream parser for that codec. If your project is to write a muxer for a container format, the qualification task may be to write the code to write the stream header.		The goal of a qualification task is to see if the mentor and student feel that, together, they will be able to finish the project of their choice. More specifically, the mentor will want to test whether the student has the skills and work ethics to complete a large coding project in a limited amount of time. The student will want to make sure that the mentor provides (useful) assistance when necessary. Therefore, students should select a mentor and a Summer of Code project before starting their work on a qualification task. The qualification task is often (but not necessarily) related to the selected project. For example, if your project will be to reverse engineer a new video codec, the qualification task may be to write a partial bitstream parser for that codec. If your project is to write a muxer for a container format, the qualification task may be to write the code to write the stream header.

-	There will be a second qualification task for every student: Pick a file of moderate size and reformat it in proper K&R style. The goal of this task is twofold: First it familiarizes students with the style that they will have to write their code in, second it demonstrates that students are able to submit patches from git and go through our review process.	+	There will be a second qualification task for every student: Pick a file of moderate size and reformat it in proper K&R style. The goal of this task is twofold: First it familiarizes students with the style that they will have to write their code in, second it demonstrates that students are able to submit patches from Git and go through our review process.

	=== Applying ===		=== Applying ===
-	While you're working on your qualification task, apply at http://www.google-melange.com/. The degree (and detail) with which you've finished your qualification task will determine how likely your project is to be selected. In the past few years, students that completely finished their qualification task always got selected as Summer of Code students, but that may vary depending on the number of spots we get assigned by Google, and the number of students that apply.	+	While you're working on your qualification task, apply at http://www.google-melange.com/. The degree (and detail) with which you've finished your qualification task will determine how likely your project is to be selected. In the past few years, students that completely finished their qualification task always got selected as Summer of Code students, but that may vary depending on the number of slots we are allotted by Google, and the number of students that apply.

	== 1st Tier Project Proposals ==		== 1st Tier Project Proposals ==
-	1st tier project proposals are project ideas that are reasonably well defined '''AND''' have a mentor volunteered.	+	1st tier project proposals are project ideas that are reasonably well defined '''AND''' have a mentor.

	=== Hardware Acceleration API ===		=== Hardware Acceleration API ===

-	Libav has two different and incomplete api to provide hardware acceleration wrapping, the project should provide a better abstraction and migrate the currently implemented ones and additional provide more.	+	Libav has two different and incomplete APIs to provide hardware acceleration wrapping. The project should improve the available abstraction, migrate the currently implemented ones and add more hardware acceleration interfaces.

-	* Draft the API (that will require knowledge of libavcodec)	+	* Draft the API (that will require knowledge of libavcodec).
	* Port vaapi/hwaccel to the new API.		* Port vaapi/hwaccel to the new API.
-	* Port vdpau to the new API	+	* Port VDPAU to the new API.
-	* Implement Freescale VPU support	+	* Implement Freescale VPU support.
-	* Implement TI dce support	+	* Implement TI dce support.

	'''Mentor: [[User:lu_zero\|Luca Barbato]]'''		'''Mentor: [[User:lu_zero\|Luca Barbato]]'''
Line 39:		Line 39:
	=== VP9 Native Decoder ===		=== VP9 Native Decoder ===

-	The WebM team is refining the evolution of their VP8 codec using a number of additional tools and tunings, the project involves providing a baseline	+	The WebM team is refining the evolution of their VP8 codec using a number of additional tools and tunings. The project involves providing a baseline
-	decoder as first step and optimize it to be at least as fast as the vpx one on one of the most used architectures (arm and x86_64).	+	decoder as first step and optimizing it to be at least as fast as the libvpx one on one of the most used architectures (ARM and x86_64).

	'''Mentor: [[User:lu_zero\|Luca Barbato]]'''		'''Mentor: [[User:lu_zero\|Luca Barbato]]'''

-	=== Webp Lossless Native codec and webp Lossy decoder ===	+	=== WebP Lossless Native codec and WebP Lossy decoder ===

-	The webp is a quite promising image format that could superceed [[JPEG]] and [[PNG]] as common format for web images, it leverages vp8 for lossy	+	WebP is a promising image format that could supercede [[JPEG]] and [[PNG]] as common format for web images, it leverages VP8 for lossy
-	encoding and uses a relatively simple original format for the lossless part	+	encoding and uses a relatively simple original format for the lossless part.

-	The project is split in a number of easy tasks, such as writing a decoder for both the lossy and the lossless mode and a much harder task that is providing a good encoder for the lossless part, at least. (exceptional praise for producing a good lossy encoder but it is not required).	+	The project is split in a number of easy tasks, such as writing a decoder for both the lossy and the lossless mode and a much harder task that is providing a good encoder for the lossless part, at least. (Exceptional praise for producing a good lossy encoder but it is not required.)

	'''Mentor: [[User:lu_zero\|Luca Barbato]]'''		'''Mentor: [[User:lu_zero\|Luca Barbato]]'''
Line 55:		Line 55:
	=== Native DVD support ===		=== Native DVD support ===

-	Currently most of the opensource support for DVD is available through the use of libdvdread and libdvdnav, currently there is some effort to unify them	+	Most of the open source support for DVDs is available through libdvdread and libdvdnav. Currently there is some effort to unify them
-	in a single library (libdvd5). An additional step would be factor it in the libav codebase the non interactive part of it to leverage even more code and leave as stand alone library the parts that require some kind of interaction.	+	in a single library (libdvd5). An additional step would be factoring the non-interactive part of into the libav codebase to leverage even more code and leave as stand alone library the parts that require some kind of interaction.

	'''Mentor: [[User:flameeyes\|Diego Pettenò]]		'''Mentor: [[User:flameeyes\|Diego Pettenò]]
Line 62:		Line 62:
	=== Restructuring the MPEG video family of codecs ===		=== Restructuring the MPEG video family of codecs ===

-	Many encoders and decoders currently use the MpegEncContext structure and its associated API. This structure is a huge monolithic blob which combines the feature of all those encoders and decoders, thus making it very fragile and hard to understand.	+	Many encoders and decoders currently use the MpegEncContext structure and its associated API. This structure is a huge monolithic blob which combines the features of all those encoders and decoders, thus making it very fragile and hard to understand.

-	The goal of this project would be splitting out parts of the MpegEncContext API into self-contained structures that would be easier to grasp, while still allowing code reuse where appropriate.	+	The goal of this project is splitting out parts of the MpegEncContext API into self-contained structures that would be easier to grasp, while still allowing code reuse where appropriate.

	'''Mentor: [[User:elenril\|Anton Khirnov]]		'''Mentor: [[User:elenril\|Anton Khirnov]]

Cinepak

2013-02-12T15:24:59Z

adjusted the information as the situation changes

Revision as of 15:24, 12 February 2013		Current revision
Line 14:		Line 14:
	http://titan.codemill.se/~tomhar/cinepakenc.patch		http://titan.codemill.se/~tomhar/cinepakenc.patch

-	Unfortunately both this open source encoder and the decoder present in ffmpeg are using the non-compliant YUV420 colorspace instead of the native Cinepak one (should be easy to fix).	+	Unfortunately the open source decoder present in ffmpeg is using the non-compliant YUV420 colorspace instead of the native Cinepak one (for the fix see below).

-	The mentioned open source encoder was recently adapted for the current (December 2012) ffmpeg and bugfixed by Rl. For a (not necessarily the latest) snapshot see	+	The encoder mentioned above was adapted for the current (December 2012) ffmpeg, bugfixed and improved for better rate/distortion performance by Rl. The compression speed is barely optimized (it is slow), for simplicity and better r/d. A snapshot 2013-02-12 is at
	http://www.aetey.se/dl/cinepak-encoder-ffmpeg.patch		http://www.aetey.se/dl/cinepak-encoder-ffmpeg.patch
		+
		+	There is also a patch introducing the correct colorspace for the open source decoder
		+	http://www.aetey.se/dl/cinepak-decoder-colorspace.patch

	The encoder was never submitted for inclusion in ffmpeg, feel free to push it upstream.		The encoder was never submitted for inclusion in ffmpeg, feel free to push it upstream.

	[[Category:Video Codecs]]		[[Category:Video Codecs]]

Libav Summer Of Code 2013

2013-02-12T08:39:06Z

/* 1st Tier Project Proposals */

Revision as of 08:39, 12 February 2013		Current revision
Line 59:		Line 59:

	'''Mentor: [[User:flameeyes\|Diego Pettenò]]		'''Mentor: [[User:flameeyes\|Diego Pettenò]]
		+
		+	=== Restructuring the MPEG video family of codecs ===
		+
		+	Many encoders and decoders currently use the MpegEncContext structure and its associated API. This structure is a huge monolithic blob which combines the feature of all those encoders and decoders, thus making it very fragile and hard to understand.
		+
		+	The goal of this project would be splitting out parts of the MpegEncContext API into self-contained structures that would be easier to grasp, while still allowing code reuse where appropriate.
		+
		+	'''Mentor: [[User:elenril\|Anton Khirnov]]

Libav Summer Of Code 2013

2013-02-12T00:37:54Z

/* VP9 Native Decoder */

Revision as of 00:37, 12 February 2013		Current revision
Line 35:		Line 35:
	* Implement TI dce support		* Implement TI dce support

-	''Mentor: [[User:lu_zero\|Luca Barbato]]''	+	'''Mentor: [[User:lu_zero\|Luca Barbato]]'''

	=== VP9 Native Decoder ===		=== VP9 Native Decoder ===
Line 42:		Line 42:
	decoder as first step and optimize it to be at least as fast as the vpx one on one of the most used architectures (arm and x86_64).		decoder as first step and optimize it to be at least as fast as the vpx one on one of the most used architectures (arm and x86_64).

-	'''Mentor: [[User:lu_zero\|Luca Barbato]]''	+	'''Mentor: [[User:lu_zero\|Luca Barbato]]'''

		+	=== Webp Lossless Native codec and webp Lossy decoder ===
		+
		+	The webp is a quite promising image format that could superceed [[JPEG]] and [[PNG]] as common format for web images, it leverages vp8 for lossy
		+	encoding and uses a relatively simple original format for the lossless part
		+
		+	The project is split in a number of easy tasks, such as writing a decoder for both the lossy and the lossless mode and a much harder task that is providing a good encoder for the lossless part, at least. (exceptional praise for producing a good lossy encoder but it is not required).
		+
		+	'''Mentor: [[User:lu_zero\|Luca Barbato]]'''

	=== Native DVD support ===		=== Native DVD support ===

User:Lu zero

2013-02-12T00:24:14Z

Revision as of 00:24, 12 February 2013		Current revision
Line 1:		Line 1:
-	Luca Barbato is a Gentoo developer that sometimes works on [[MPlayer]] and [[FFmpeg]].	+	Luca Barbato is a Gentoo developer that sometimes works on [http://videolan.org VLC] and [[Libav]].

Libav Summer Of Code 2013

2013-02-12T00:22:31Z

New page

== How it works ==

Google's Summer of Code program is simple: you (the student) work on a project, full-time, during the whole summer, and you get assistance (advice, mentoring) from a seasoned Libav developer who knows his way around the project and has considerable standing in the community. By doing so, you'll learn to operate in an opensource project, you'll get relevant coding experience, and you'll have a chance at earning money while doing fun stuff during the summer. So, you need a project, a mentor, do a qualification task (see below) so we can quickly assess how good a candidate we feel you'll be for the program, and then you can apply.

=== Selecting a project ===
Below, you'll find two lists of projects:
* Projects with a mentor
* Projects without a mentor
If you choose a project with a mentor, talk to that mentor (see below) and select a suitable qualification task. Once completed, you're eligible for participating in our Summer of Code program. If you choose a project without a mentor, your first job is to find a mentor (see below). Then, once you've found a mentor, continue as before. If you don't like any of the projects, you're free to define your own project and find a mentor as mentioned before (see below for caveats).

=== Contacting developers/mentors ===
Once you've found a project (with or without mentor), start talking to the developers of the Libav project. We can often be found on IRC, and you can talk to us on mailinglists also. Hop on irc.freenode.net channel #libav-devel, or talk to us on libav-devel@libav.org. Here, you'll be able to ask around for mentors for projects without a mentor if you need to. If you're trying to define your own project, explain (with reasonable amount of detail) what you intend to achieve and why you think your project should be in our Summer of Code program. Once you've found a mentor, you're good to start your qualification task.

Note that the self-selected mentor needs to have considerable standing in the community to be eligible for mentoring. Likewise, if you choose to define your own Summer of Code project, some community members of considerable standing need to vouch for your project.

=== Your qualification task ===
The goal of a qualification task is to see if the mentor and student feel that, together, they will be able to finish the project of their choice. More specifically, the mentor will want to test whether the student has the skills and work ethics to complete a large coding project in a limited amount of time. The student will want to make sure that the mentor provides (useful) assistance when necessary. Therefore, students should select a mentor and a Summer of Code project before starting their work on a qualification task. The qualification task is often (but not necessarily) related to the selected project. For example, if your project will be to reverse engineer a new video codec, the qualification task may be to write a partial bitstream parser for that codec. If your project is to write a muxer for a container format, the qualification task may be to write the code to write the stream header.

There will be a second qualification task for every student: Pick a file of moderate size and reformat it in proper K&R style. The goal of this task is twofold: First it familiarizes students with the style that they will have to write their code in, second it demonstrates that students are able to submit patches from git and go through our review process.

=== Applying ===
While you're working on your qualification task, apply at http://www.google-melange.com/. The degree (and detail) with which you've finished your qualification task will determine how likely your project is to be selected. In the past few years, students that completely finished their qualification task always got selected as Summer of Code students, but that may vary depending on the number of spots we get assigned by Google, and the number of students that apply.

== 1st Tier Project Proposals ==
1st tier project proposals are project ideas that are reasonably well defined '''AND''' have a mentor volunteered.

=== Hardware Acceleration API ===

Libav has two different and incomplete api to provide hardware acceleration wrapping, the project should provide a better abstraction and migrate the currently implemented ones and additional provide more.

* Draft the API (that will require knowledge of libavcodec)
* Port vaapi/hwaccel to the new API.
* Port vdpau to the new API
* Implement Freescale VPU support
* Implement TI dce support

''Mentor: [[User:lu_zero|Luca Barbato]]''

=== VP9 Native Decoder ===

The WebM team is refining the evolution of their VP8 codec using a number of additional tools and tunings, the project involves providing a baseline
decoder as first step and optimize it to be at least as fast as the vpx one on one of the most used architectures (arm and x86_64).

'''Mentor: [[User:lu_zero|Luca Barbato]]''

=== Native DVD support ===

Currently most of the opensource support for DVD is available through the use of libdvdread and libdvdnav, currently there is some effort to unify them
in a single library (libdvd5). An additional step would be factor it in the libav codebase the non interactive part of it to leverage even more code and leave as stand alone library the parts that require some kind of interaction.

'''Mentor: [[User:flameeyes|Diego Pettenò]]

Cinepak

2013-02-08T20:56:01Z

Revision as of 20:56, 8 February 2013		Current revision
Line 1:		Line 1:
	* FourCC: CVID		* FourCC: CVID
	* Company: [[Supermac]], [[Radius]], [[Providenza & Boekelheide, Inc.]]		* Company: [[Supermac]], [[Radius]], [[Providenza & Boekelheide, Inc.]]
-	* Official Website: [http://www.probo.com/cinepak.htm http://www.probo.com/cinepak.htm]
	* Technical Description: http://www.csse.monash.edu.au/%7etimf/videocodec/cinepak.txt ([[Mirrored Files\|mirrored]])		* Technical Description: http://www.csse.monash.edu.au/%7etimf/videocodec/cinepak.txt ([[Mirrored Files\|mirrored]])
	* Samples: [http://samples.mplayerhq.hu/V-codecs/CVID/ http://samples.mplayerhq.hu/V-codecs/CVID/]		* Samples: [http://samples.mplayerhq.hu/V-codecs/CVID/ http://samples.mplayerhq.hu/V-codecs/CVID/]
		+	* Windows binary codec: [http://www.probo.com/cinepak.htm http://www.probo.com/cinepak.htm]

	The Cinepak coding method is a vector quantization scheme with interframe update optimization. It is known to operate most commonly using a modified YUV 4:2:0 colorspace but also supports 256-grayscale mode. A modified variant of this format is used for full motion video on many Sega Saturn games (in [[Sega FILM]] files often bearing the .cpk extension). It is not known if this format has anything in common with the [[Cinepak For Sega]] format used in many Sega CD games.		The Cinepak coding method is a vector quantization scheme with interframe update optimization. It is known to operate most commonly using a modified YUV 4:2:0 colorspace but also supports 256-grayscale mode. A modified variant of this format is used for full motion video on many Sega Saturn games (in [[Sega FILM]] files often bearing the .cpk extension). It is not known if this format has anything in common with the [[Cinepak For Sega]] format used in many Sega CD games.
Line 11:		Line 11:
	There are several versions of a binary proprietary encoder/decoder as a windows dll, among others ftp://ftp.probo.com/pub/cinepak/cvid32.zip		There are several versions of a binary proprietary encoder/decoder as a windows dll, among others ftp://ftp.probo.com/pub/cinepak/cvid32.zip

-	There is also a simple and straightforward open source encoder as a ffmpeg patch, written in 2011 by [does the person want his name here??] and formerly available at	+	There is also a simple and straightforward open source encoder as a ffmpeg patch, written in 2011 by Tomas Härdin and available at
-	http://titan.codemill.se/~tomhar/cinepakenc.patch (a dead link), see the thread http://multimedia.cx/eggs/playing-video-on-a-sega-dreamcast/	+	http://titan.codemill.se/~tomhar/cinepakenc.patch

-	Unfortunately the open source encoder does not use all the possibilities of the format (f.i. skipped or partial codebook replacement). This is the probable reason why it does not achieve the performance of the proprietary one. It is also using the non-compliant YUV420 colorspace (should be easy to fix).	+	Unfortunately both this open source encoder and the decoder present in ffmpeg are using the non-compliant YUV420 colorspace instead of the native Cinepak one (should be easy to fix).

-	The mentioned open source encoder was recently adapted for the current (December 2012) ffmpeg and slightly improved. It is available at	+	The mentioned open source encoder was recently adapted for the current (December 2012) ffmpeg and bugfixed by Rl. For a (not necessarily the latest) snapshot see
	http://www.aetey.se/dl/cinepak-encoder-ffmpeg.patch		http://www.aetey.se/dl/cinepak-encoder-ffmpeg.patch

Providenza & Boekelheide

2013-02-06T13:46:38Z

changed the strange wording "owns technology" to "owns trademark" which may be true (?)

Revision as of 13:46, 6 February 2013		Current revision
Line 1:		Line 1:
	Website: [http://www.probo.com/ http://www.probo.com/]		Website: [http://www.probo.com/ http://www.probo.com/]

-	Providenza & Boekelheide, Inc. presently owns the [[Cinepak]] technology.	+	Providenza & Boekelheide, Inc. allegedly presently owns the [[Cinepak]] trademark (any reference?).

	[[Category:Multimedia-related Companies]]		[[Category:Multimedia-related Companies]]

Revision as of 02:02, 14 February 2013		Current revision
Line 3:		Line 3:
	* [[Libav Summer Of Code 2013\|2013 Libav project page]]		* [[Libav Summer Of Code 2013\|2013 Libav project page]]
	* [[Libav Summer Of Code 2012\|2012 Libav project page]]		* [[Libav Summer Of Code 2012\|2012 Libav project page]]
		+	* [[FFmpeg_Summer_of_Code_2012\|2012 FFmpeg Project page]]
	* [[FFmpeg / Libav Summer Of Code 2011\|2011 project page]]		* [[FFmpeg / Libav Summer Of Code 2011\|2011 project page]]
	* [[FFmpeg Summer Of Code 2010\|2010 project page]]		* [[FFmpeg Summer Of Code 2010\|2010 project page]]