[FFmpeg-devel] [RFC] Google Summer of Code 2013

compn tempn at twmi.rr.com
Thu Feb 28 01:49:57 CET 2013

On Wed, 27 Feb 2013 22:09:20 +0100, Michael Niedermayer wrote:
>On Wed, Feb 27, 2013 at 08:41:54PM +0100, Maxim Polijakowski wrote:
>> Am 27.02.2013 20:15, schrieb Michael Niedermayer:
>> >On Wed, Feb 27, 2013 at 07:29:38PM +0100, Maxim Polijakowski wrote:
>> >>Am 27.02.2013 16:55, schrieb Roger Pack:
>> >>>On 2/21/13, Lou Logan <lou at lrcd.com> wrote:
>> >>>>Hello,
>> >>>>
>> >>>>It's GSoC time again, so I'll get the ball rolling:
>> >>>>http://www.google-melange.com/gsoc/homepage/google/gsoc2013
>> >>>>
>> >>>>I started a new ideas list:
>> >>>>http://wiki.multimedia.cx/index.php?title=FFmpeg_Summer_of_Code_2013
>> >>>A few other wish list ideas, if anybody wants to run with them:
>> >>I suggest to remove the GoToMeeting entry from this list. It sounds
>> >>to me like another project that will never be completed in the GSoC
>> >>time frame (3 month). Let me explain why:
>> >>
>> >>- due to the fact the "decoder specification" has been created in
>> >>means of RE, it lacks the desired completeness. One need to dig into
>> >>the binary code in order to extract missing parts
>> >>
>> >>- there is two issues with the ELS coder - the heart of the coding
>> >>methods 2 and 3. Go2Meeting utilizes the augmented ELS that combines
>> >>the vanilla ELS with a some sort of Q-coder in order to increase
>> >>compression. This augmented version has been incompletely documented
>> >>by a software patent. No one in the world would be ever able to
>> >>reimplement this (weird) entropy coder using this patent alone.
>> >>
>> >>- fortunately, there is an open-source implementation of this coder
>> >>written by the author of this compression method, Mr. Douglas
>> >>Whiters. Though this code has been released under the GPL and a
>> >>relicensing is required in order to use it within FFmpeg. One need
>> >>to contact the author and ask for the appropriate permission. Should
>> >>he disagree, we'll end up having another non-free piece of code.
>> >>
>> >>- FFmpeg's implementation of the JPEG need to be extended to include
>> >>tables for Go2Meeting. The attached spec doesn't describe these
>> >>tables.
>> >quantization and or huffman tables ?
>> >are they stored in the files or constant ?
>> >
>> >if constant and a encoder is available, you can encode the output of
>> >-f lavfi mptestsrc
>> >the values for the tables can then be inferred from the generated
>> >bitstream.
>> >The alternative is to find the tables in the binary which may or may
>> >not be easier
>> Thank you for the suggestions. The tables are constant and I've
>> already extracted those from the binary because it's just plain
>> libjpeg6b...
>> I just wanted to say that the specification made by Kostya (great
>> job anyway!) is not sufficient enough to write the decoder from
>> scratch. Such "extra" knowledges are essential in order to be able
>> to finish the GSoC task...
>yes, i agree, both RE + implementation is rather difficult for s gsoc

kostya posted his incomplete decoder here:

maybe now we can troll videolan into action.


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