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FFmpeg Summer of Code 2013

2013-04-11T08:52:46Z

/* Introduction */ simplify note about project not accepted status

Revision as of 08:52, 11 April 2013		Current revision
Line 9:		Line 9:
	This is our ideas page for [http://www.google-melange.com/gsoc/homepage/google/gsoc2013 Google Summer of Code 2013].		This is our ideas page for [http://www.google-melange.com/gsoc/homepage/google/gsoc2013 Google Summer of Code 2013].

-	Note: '''FFmpeg has not been accepted this year''', so if you want to do any of the qualification tasks and projects, they are just for fun...	+	'''FFmpeg has not been accepted this year''', so if you want to do any of the qualification tasks and projects, they are just for fun.

	== Information for Students ==		== Information for Students ==

FFmpeg bug testing

2013-04-09T16:23:38Z

/* initial process */

New page

this document will try to explain the process used by bugtesters and developers to find and fix bugs in ffmpeg.

the process could be used in the future to automate bug testing. or find holes in our FATE coverage.

= example 1 - bug 2414 - wmv2 decoding artifacts =
*https://ffmpeg.org/trac/ffmpeg/ticket/2414
*sample: http://samples.ffmpeg.org/asf-wmv/wmv2decerror-short.asf

== initial process ==
#check if the official decoder/program handles the sample. it could be a broken file.
##mplayer -vc wmvdmo sample
#test sample with latest ffplay/ffmpeg.
##sometimes its already fixed.
##make sure its not an ffplay-only bug by also testing with ffmpeg.
#check with old version of ffmpeg to see if it is a regression bug.
#check if its a demuxer problem by testing with the ffmpeg/mplayer demuxer and official decoder.
##to test ffmpeg demuxer - mplayer -demuxer lavf -vc wmvdmo
##to test mplayer demuxer - mplayer -demuxer asf -vc wmvdmo

now that we know its not a demuxer problem, we can move onto debugging the decoder.

=== advanced codec debugging ===
#test if codec cpu optimizations are not binary identical to the c-version of the codec
##use ffmpeg -cpuflags 0 , ffmpeg has to be compiled with runtime cpu detection for this to work.
#test if codec asm version is not binary identical to the c-version of the codec
## recompile ffmpeg with --disable-asm

since codec also reports "dc overflow" error, check what the decoder does when it encounters this error. it is ffmpeg policy to report these errors, but also to continue decoding, in an effort to play as much of a file as possible.

in this case, msmpeg4dec.c , when encountering a dc overflow error, would return -1.
#try commenting out this in the source code, recompile, and test your changes to see if the picture changes for the better.

== results and conclusion ==
there seems to be no way to switch asm optimizations on or off at runtime. its useful to have a seperate ffmpeg binary compiled with --disable-asm to test with.

= required programs for bug testing =
bug testers should have the following installed:
#latest git ffmpeg binary with asm and cpu runtime detection enabled
#latest git ffmpeg binary with --disable-asm and cpu runtime detection
#older version ffmpeg binaries with and without asm
#official 3rd party players
##realplayer
##quicktime
##windows media player
#mplayer version with binary codec support
#vlc

FFmpeg Summer of Code 2013

2013-04-09T13:18:41Z

move and reword sentence about program status

Revision as of 13:18, 9 April 2013		Current revision
Line 8:		Line 8:

	This is our ideas page for [http://www.google-melange.com/gsoc/homepage/google/gsoc2013 Google Summer of Code 2013].		This is our ideas page for [http://www.google-melange.com/gsoc/homepage/google/gsoc2013 Google Summer of Code 2013].
		+
		+	Note: '''FFmpeg has not been accepted this year''', so if you want to do any of the qualification tasks and projects, they are just for fun...

	== Information for Students ==		== Information for Students ==

Libavfilter Shortcomings

2013-04-09T08:37:53Z

remove addresed stuff

Revision as of 08:37, 9 April 2013		Current revision
Line 1:		Line 1:
	Here a list of Libavfilter shortcomings that should be addressed:		Here a list of Libavfilter shortcomings that should be addressed:

-	* No error reporting in the callbacks
	* No support for reconfiguration		* No support for reconfiguration
-	* No way to provide a filter help with parameters
	* Avisynth-like features (script files, random access to source frames)		* Avisynth-like features (script files, random access to source frames)
	* higher-bit-depth support in most scenarios		* higher-bit-depth support in most scenarios

DFA

2013-04-08T09:47:25Z

/* TDLT chunk */ Uploaded to game-formats/chronomaster-dfa/

Revision as of 09:47, 8 April 2013		Current revision
Line 125:		Line 125:
	output <- getbytes(numcopy * 2)		output <- getbytes(numcopy * 2)
	}		}
-
-	''Can't upload a sample to mplayerhq, grab it here and reupload yourself: http://www.sendspace.com/file/a9bn4j -- [[User:VAG\|VAG]] 11:01, 6 April 2013 (EDT)''

	=== DSW1 chunk ===		=== DSW1 chunk ===

DFA

2013-04-06T15:01:59Z

/* TDLT chunk */ tdlt sample file

Revision as of 15:01, 6 April 2013		Current revision
Line 126:		Line 126:
	}		}

-	Sample NEEDED!	+	''Can't upload a sample to mplayerhq, grab it here and reupload yourself: http://www.sendspace.com/file/a9bn4j -- [[User:VAG\|VAG]] 11:01, 6 April 2013 (EDT)''

	=== DSW1 chunk ===		=== DSW1 chunk ===

DFA

2013-04-06T12:26:42Z

/* TDLT chunk */

Revision as of 12:26, 6 April 2013		Current revision
Line 125:		Line 125:
	output <- getbytes(numcopy * 2)		output <- getbytes(numcopy * 2)
	}		}
		+
		+	Sample NEEDED!

	=== DSW1 chunk ===		=== DSW1 chunk ===

DFA

2013-04-05T23:05:31Z

typo

Revision as of 23:05, 5 April 2013		Current revision
Line 2:		Line 2:
	* Samples: [http://samples.mplayerhq.hu/game-formats/chronomaster-dfa/ http://samples.mplayerhq.hu/game-formats/chronomaster-dfa/]		* Samples: [http://samples.mplayerhq.hu/game-formats/chronomaster-dfa/ http://samples.mplayerhq.hu/game-formats/chronomaster-dfa/]

-	A DOS-based game called [http://www.mobygames.com/game/dos/chronomaster Chronomaster] includes files with the extension .dfa which appear to be animation files. All multi-byte numbers are little endian. These files are comprised of chunks with the following format:	+	DFA is a FMV format used in PC games developed by DreamForge.
		+
		+	== File format ==
		+
		+	All multi-byte numbers are little endian. These files are comprised of chunks with the following format:

	bytes 0-3 chunk fourcc		bytes 0-3 chunk fourcc
Line 12:		Line 16:

	bytes 0-3 file signature: 'DFIA'		bytes 0-3 file signature: 'DFIA'
		+	byte 4 version (= 0)
		+	byte 5 ? (output)
	bytes 6-7 number of frames		bytes 6-7 number of frames
	bytes 8-9 frame width		bytes 8-9 frame width
	bytes 10-11 frame height		bytes 10-11 frame height
	bytes 12-15 frame rate		bytes 12-15 frame rate
-	bytes 16-19 ?	+	bytes 16-19 first frame offset (= 0x80)
-	bytes 20-127 unused	+	bytes 20-23 ? (odirectory)
		+	bytes 24-127 unused

	Chunk types include:		Chunk types include:
Line 27:		Line 34:
	BDLT (type 4) video frame, inter RLE-coded bytes		BDLT (type 4) video frame, inter RLE-coded bytes
	WDLT (type 5) video frame, inter RLE-coded words		WDLT (type 5) video frame, inter RLE-coded words
-	type 6 not occured in known samples	+	TDLT (type 6) video frame, inter chains
	DSW1 (type 7) video frame, inter LZ-coded		DSW1 (type 7) video frame, inter LZ-coded
	BLCK (type 8) solid frame, fill whole frame with the first byte of payload		BLCK (type 8) solid frame, fill whole frame with the first byte of payload
Line 106:		Line 113:
	}		}

-	=== chunk type 6 ===	+	=== TDLT chunk ===

-	First four bytes code number of segments, each segment contains number of bytes to skip before decoding, number of bytes to copy and bytes to copy.	+	First four bytes code number of segments, each segment contains number of words to skip before decoding, number of words to copy and bytes to copy.
		+
		+	segments = getdword()
		+	while(segments--)
		+	{
		+	numcopy = getbyte()
		+	numskip = getbyte()
		+	output += numskip * 2
		+	output <- getbytes(numcopy * 2)
		+	}

	=== DSW1 chunk ===		=== DSW1 chunk ===
Line 150:		Line 166:
	}		}

		+	== Games using DFI ==
		+	* [http://www.mobygames.com/game/anvil-of-dawn Anvil of Dawn]
		+	* [http://www.mobygames.com/game/dos/chronomaster Chronomaster]
		+
	[[Category:Game Formats]]		[[Category:Game Formats]]

User:Puggsoy

2013-04-05T15:56:32Z

New page

Hi, I'm Puggsoy. I'm a Flash developer, although most of my experience is with creating desktop apps (using AIR).

I was looking for information about the the [[BLB]] format, and I found this wiki. I'm currently trying to find out more about the format, and will update the page accordingly.

FFmpeg Summer of Code 2013

2013-04-05T07:13:40Z

/* Hardware Accelerated Video Encoding with VA-API */ add Tushar Gohad as backup mentor

Revision as of 07:13, 5 April 2013		Current revision
Line 286:		Line 286:
	'''Mentor:''' [[User:Gwenole_Beauchesne\|Gwenole Beauchesne]] (''__gb__'' on IRC)		'''Mentor:''' [[User:Gwenole_Beauchesne\|Gwenole Beauchesne]] (''__gb__'' on IRC)

-	'''Backup Mentor:''' [[User:Stefanosa\|Stefano Sabatini]] (''saste'' on IRC)	+	'''Backup Mentor:''' Tushar Gohad

	<br clear="all"/>		<br clear="all"/>