[Ffmpeg-devel] lzw compression in tiff encoder (qualification task for GSoC)

Bartlomiej Wolowiec b.wolowiec
Fri Apr 6 18:07:57 CEST 2007

On Friday 06 April 2007 15:30, Baptiste Coudurier wrote:
> Hi
> Bartlomiej Wolowiec wrote:
> > Hi,
> > As a supplement to my qualification task for GSoC I implemented LZW
> > compressor. I think that my code is fast, universal and it can be easily
> > used in other encoders. My implementation use hash table with simple hash
> > function (I've used LZW prefix code and xor to calculate new hash value).
> > So, I'm sending two files: one with lzw encoder (lzw.patch) and one with
> > patch to tiffenc.c (tifflzw.patch).
> Good, you may be interested in using your lzw encoder with gif also,
> which atm does not use lzw compression.
> I also quickly tested tiff encoder, and unfortunately it does not play
> in quicktime, if you can have a look.

in my test quicktime play lzw tiff, but does not play zlib (deflate) tiff...
Can you send broken file ?

lzw compress:
./ffmpeg -y -i film.avi -compression_level 2 -vcodec tiff -f mov -an out.mov

zlib compress:
./ffmpeg -y -i film.avi -compression_level 3 -vcodec tiff -f mov -an out.mov

Also, Kamil Nowosad is working on improving the choice of compression in 

Best Regards,

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