MultimediaWiki - Recent changes [en]

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]]

Cinepak

2013-02-03T21:53:45Z

added description of available encoders/decoders

Revision as of 21:53, 3 February 2013		Current revision
Line 5:		Line 5:
	* 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/]

-	The Cinepak coding method is a vector quantization scheme with interframe motion compensation. It is known to operate most commonly using a modified YUV 4:2:0 colorspace but also supports 256-grayscale mode and palettized 8-bit 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.
		+
		+	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 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
		+	http://titan.codemill.se/~tomhar/cinepakenc.patch (a dead link), see the thread http://multimedia.cx/eggs/playing-video-on-a-sega-dreamcast/
		+
		+	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).
		+
		+	The mentioned open source encoder was recently adapted for the current (December 2012) ffmpeg and slightly improved. It is available at
		+	http://www.aetey.se/dl/cinepak-encoder-ffmpeg.patch
		+
		+	The encoder was never submitted for inclusion in ffmpeg, feel free to push it upstream.

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

Bayer RGB

2013-01-31T23:59:37Z

fix url

Revision as of 23:59, 31 January 2013		Current revision
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	* FourCCs: BA81, BYR1		* FourCCs: BA81, BYR1
-	* Description: http://www.linuxtv.org/downloads/video4linux/API/V4L2_API/spec-single/v4l2.html#V4L2-PIX-FMT-SBGGR8	+	* Description: http://linuxtv.org/downloads/v4l-dvb-apis/V4L2-PIX-FMT-SBGGR8.html
		+	* rejected MPlayer patch: http://lists.mplayerhq.hu/pipermail/mplayer-dev-eng/2008-March/056719.html

	Bayer RGB is a pixel format that reflects the layout of sensors in a CCD device - 1 red, 2 green, and 1 blue in a 2x2 sensor grid.		Bayer RGB is a pixel format that reflects the layout of sensors in a CCD device - 1 red, 2 green, and 1 blue in a 2x2 sensor grid.

VP9

2013-01-29T07:42:14Z

initial information

New page

* FOURCCs: VP90
* Description: ???
* Code : http://git.chromium.org/gitweb/?p=webm/libvpx.git;a=summary
* Samples: ???

VP9 is an open and royalty free video compression standard being developed by Google. VP9 had earlier development names of Next Gen Open Video (NGOV) and VP-Next. VP9 is a successor to VP8.

A test (not pretending to be scientific or reliable) from 17th January 2013 is present in the discussion thread
http://forum.doom9.org/showthread.php?p=1610941

Daala

2013-01-29T07:28:02Z

initial information

New page

* FOURCCs: ?
* Description: https://wiki.xiph.org/Daala
* Code in progress : git clone https://git.xiph.org/daala.git
* Samples: none yet

Daala is the current working name of a next generation video codec. The effort is a collaboration between Mozilla Foundation, Xiph.Org Foundation and other contributors.

The goal of the project is to provide a free to implement, use and distribute digital media format and reference implementation with technical performance superior to h.265.

The development suffered at the end of 2012 due to the developers being involved in short term [[Opus]]-related activities. The availability of [[VP9]] since January 2013 also may influence the amount of resources being allotted to Daala.

Dirac

2013-01-28T13:47:11Z

replaced obsoleted summary, dirac is now stable

Revision as of 13:47, 28 January 2013		Current revision
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	* Samples: [http://samples.libav.org/V-codecs/Dirac/ Libav Samples] [http://diracvideo.org/download/test-streams/raw/ DiracVideo Samples]		* Samples: [http://samples.libav.org/V-codecs/Dirac/ Libav Samples] [http://diracvideo.org/download/test-streams/raw/ DiracVideo Samples]

-	Experimental wavelet-based video codec being developed by the [[BBC]]. The development of a C++ Dirac implementation under the MPL license called libdirac is hosted at SourceForge.	+	Wavelet-based video codec developed by the [[BBC]]. The development of a C++ Dirac implementation under the MPL license called libdirac is hosted at SourceForge.
	[http://schrodinger.sf.net The Schrödinger Project] is an implementation written in ANSI C89, jointly developed by [[Fluendo]] and [[BBC]].		[http://schrodinger.sf.net The Schrödinger Project] is an implementation written in ANSI C89, jointly developed by [[Fluendo]] and [[BBC]].

-	A Dirac decoder and encoder has been developed as part of [[FFmpeg Summer Of Code#Dirac_Encoder_and_Decoder\|FFmpeg's Summer of Code 2007]] but has not yet been committed.	+	The Schroedinger C implementation has surpassed the quality of the original C++ libdirac one.
		+
		+	FFmpeg supports both encoding and decoding via libschroedinger.
		+
		+	Dirac performance is in the same range as MPEG4 or Theora (quite possibly better for high bitrates) but it is unfortunately much more CPU-intensive. The compression artifacts look different in Dirac compared to the DCT-based codecs, thus a preference may be a matter of personal taste.

	== About Wavelets ==		== About Wavelets ==
-	Continuous Wavelet Transform (CWT) is an alternative to the Windowed Fourier Transform (WFT). The data analysis at different factor or resolutions is the main difference between CWT and WFT, also called multi-resolution analysis (MRA) which is also the justification for the algorithm of the Fast Wavelet Transform (FWT). In front of Fourier Transform which has only the sin() and cs() functions available, the Wavelet transform has infinite available functions, with that property the access to the information is immediate. The WFT projects a time function (the signal) into a A and B function, where A is known as scale and B is known as translation. A and B are also known as 'mother wavelet' and 'child wavelets'. A and B could be Quadrature Mirror Filter (QMF).	+	Continuous Wavelet Transform (CWT) is an alternative to the Windowed Fourier Transform (WFT). The data analysis at different factor or resolutions is the main difference between CWT and WFT, also called multi-resolution analysis (MRA) which is also the justification for the algorithm of the Fast Wavelet Transform (FWT). '''['''In front of Fourier Transform which has only the sin() and cos() functions available, the Wavelet transform has infinite available functions, with that property the access to the information is immediate. -- an odd-looking statement? -- Rl''']''' The WFT projects a time function (the signal) into a A and B function, where A is known as scale and B is known as translation. A and B are also known as 'mother wavelet' and 'child wavelets'. A and B could be Quadrature Mirror Filter (QMF).

	The Fast Wavelet Transform is designed to turn a waveform in the time domain into a sequence of coefficients based on an orthogonal basis of small finite waves or wavelets. The transform can be easily extended from time to other domains like images (2D-WT) or videos (3D-WT).		The Fast Wavelet Transform is designed to turn a waveform in the time domain into a sequence of coefficients based on an orthogonal basis of small finite waves or wavelets. The transform can be easily extended from time to other domains like images (2D-WT) or videos (3D-WT).

Small FFmpeg Tasks

2013-01-25T14:27:20Z

/* vcr1 encoder */ questionable usefulness, also template have been removed

Revision as of 14:27, 25 January 2013		Current revision
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	http://ffmpeg.org/trac/ffmpeg/ticket/317		http://ffmpeg.org/trac/ffmpeg/ticket/317

-	=== vcr1 encoder ===	+
-	According to this: http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2009-February/063555.html vcr1 encoder is disabled, and won't compile if enabled. Michael would prefer to keep it around, and have someone grow it into full encoder.	+

	=== Implement Phantom Cine demuxer and Bayer format support for swscale ===		=== Implement Phantom Cine demuxer and Bayer format support for swscale ===
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	*any samples?		*any samples?

-	=== [[Enhanced Variable Rate Codec]] decoder ===	+
-	samples and specs available.	+

	=== adobe http f4f segmented fragmentation dynamic streaming format ===		=== adobe http f4f segmented fragmentation dynamic streaming format ===
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	=== get 3IV1 decoder working and benchmark ===		=== get 3IV1 decoder working and benchmark ===
	we have a decoder for 3IV1. its currently if 0'd in the mpeg4 decoder. your task is to test if it still builds and works, and fix it so that it does not slow down mpeg4 decoder if enabled. the end goal is to enable it by default.		we have a decoder for 3IV1. its currently if 0'd in the mpeg4 decoder. your task is to test if it still builds and works, and fix it so that it does not slow down mpeg4 decoder if enabled. the end goal is to enable it by default.
		+
		+	=== Extend GIF Encoder to support Animated GIFs ===

	== Reverse Engineering Tasks ==		== Reverse Engineering Tasks ==
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	[[Category:FFmpeg]]		[[Category:FFmpeg]]
-	[[Category:Libav]]

Revision as of 02:02, 14 February 2013		Current revision
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	* [[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]]