[Ffmpeg-devel] Reading bit-reversed VLC codes

Måns Rullgård mans
Mon Mar 19 10:26:18 CET 2007

Kostya <kostya.shishkov at gmail.com> writes:

> On Sun, Mar 18, 2007 at 08:10:59PM +0000, M?ns Rullg?rd wrote:
> [...]
>> I'm trying to write a zlib decoder.  The spec is RFC1951.
>> > i thought that you wanted to reverse the output of get_vlc() not the
>> > bits of the vlc codes as stored in the bitstream later wont work in
>> > general example:
>> [...]
>> > init_vlc/get_vlc() doesnt support such non prefix codes (for obvious
>> > reasons)
>> No, of course it doesn't.  Do you have any suggestion how to solve
>> this?
> Look at indeo2.c as it's the first decoder used "reverse" codes.
> I also tried to implement zlib but that is too tricky to do.
> Here is my code to the point when I gave up. 

I got it working after fixing init_vlc().  Now I just need to make it
handle multiple blocks and wrap it in a nice API.

M?ns Rullg?rd
mans at mansr.com

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