[FFmpeg-devel] Interest in Apple Lossless Encoder and JPEG 2000 Encoder and Decoder as Quanlification Task

Michael Niedermayer michaelni
Sat Mar 29 14:24:03 CET 2008


On Fri, Mar 28, 2008 at 11:05:11PM -0600, Lily Zhang wrote:
> Dear All,
> 
> My name is Lily, a graduate students in EE, focusing on Multimedia and image
> processing. I am very interested in the project: Apple Lossless Encoder. I
> have been working on H.264 codec design in the past 2 years. Most of my work
> is on video/image compression(MPEG/JPEG codec design, DSC coding), but I
> really wanna do sth. on audio in GoSoc. I should say I am quite familiar
> with the codec structure and the popular video and audio standards.
> 
> As for the qualification task, I would like to work on JPEG 2000 Encoder and
> Decoder. I noticed that Abhishak is working on the decoder part, and I would
> like to take up the encoder part. I have already implemented Jpeg encoder
> myself, so I think it will be a good start point.
> 

> Can anyone give some info on at what state the code is?

It seems to be working, oddly, last time i looked at it only few out of 50
encoded images were decodeble by jasper. But now it seems all 50 decode
mostly correctly.


> What features you
> would like me to implement?

I think the main thing would not be to implment more feature but to
clean the code up so we can commit it to ffmpeg svn. Of course any bugs
we stumble across while doing that should be fixed as well. I thought the
encoder was more buggy than it seems to be now ...

Also iam not sure if the j2k encoder cleanup is not maybe too hard as
qualification task in the time remaining, especially if i look at how
others struggle to cleanup their own, much simpler code.
The "Optimal Huffman tables for (M)JPEG" task has become available again
as the student who worked on it has disappeared and not replied to mails
since a week.
Of course if you do want to try to cleanup the jpeg2000 encoder code as
qualification task so we can commit it to svn i certainly wont stop you.

If you do want to work on the j2k encoder, first thing would be to simply
take the current code, make a patch against ffmpeg svn out of it and submit
it here. Ill then review it and say what needs to be cleaned up.
After doing the requested changes, you submit a new patch i review it again,
... until i fail to find things which can be improved or cleaned up.
Its the same with any other patch submitted here ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Concerning the gods, I have no means of knowing whether they exist or not
or of what sort they may be, because of the obscurity of the subject, and
the brevity of human life -- Protagoras
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