[Ffmpeg-devel] VC-1 stream handling

Ian Caulfield ian.caulfield
Mon Jan 15 17:36:34 CET 2007


I've been working on adapting FFmpeg to handle VC-1 elementary streams, as
well as muxing/demuxing VC-1 in MPEG-PS. I've written the PS muxing/demuxing
code, but currently I'm having a problem getting the vc1 codec to handle it,
as currently the vc1 codec is set up to work with WVC1 streams in ASF, which
have the picture startcodes stripped and the sequence header stored in
extradata. I'm just wondering what the best way to handle this would be.

- The VC-1 decoder code could be modified to handle a VC-1 bitstream as well
as the current stripped format from ASF, but it wouldn't be possible to do
MPEG<->WMV remuxing of VC-1 streams

- The ASF parser could reassemble the elementary stream (stick the headers
from extradata on the front, add 0000010d before each picture) - I knocked
up some rough code to do this to allow VC-1 demuxing from asf, but this
still requires modifications to the vc1 codec, and introduces some
codec-dependent code into the asf demuxer, which isn't very pleasant.

What would be the best way to handle this? I'm happy to do coding.


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