[FFmpeg-devel] [PATCH] Unfinished GSoC qual task (16bit VQA Video Decoder)

[Adam Iglewski]

Hi,

I was tracking (I really wanted to see videos from BladeRunner again :)) 
the progress of this task and it looks like The Deep Explorer finally 
gave up. I had some spare time so I thought I will give a try. So here 
it is.

I'm sending 3 patches:

add_vqa_hc - adds decoding of HC video chunks. I'm not sure about parts
that I added in vqa_decode_frame function. I don't know well
ffmpeg internals so I based my changes on msvideo1 decoder.

mod_westwood_dmux - modifies demuxer to recognize new chunks in hc files

fix_adpcm_ws - fixes decoding of stereo audio.

Non patched ffmpeg plays distorted sound on files with 2 channels. 
Description of SND2 chunk

http://wiki.multimedia.cx/index.php?title=VQA#SND2_chunk

says that in stereo files first half of chunk is for left channel and
second half for right channel but the code doesn't match the
description. But code for decoding nibbles for codec with id
CODEC_ID_ADPCM_4XM does. So I just replaced relevant parts and now it
plays fine but there is slight desync between video and audio when
playing files in ffplay. Any hints how to fix this?

Adam

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