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

Maxim Polijakowski max_pole at gmx.de
Wed Feb 27 19:29:38 CET 2013

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.

Remember the Atrac3plus task: 
Due to the similar conditions (incomplete spec, RE skills required) this 
task has been never completed. It took two years!!! in order to finish 
the decoder (which I'll publish soon)...

Therefore, I suggest to find another way to get a decoder for G2M. I 
already wrote some working code two month ago. It's unfinished but I 
could give it away to someone who want to complete it. I could share my 
own knowledges about debugging and using the original G2M libraries as 

Best regards

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