[FFmpeg-devel] Handling CODEC_FLAG2_CHUNKS type H264 content.

Michael Niedermayer michaelni at gmx.at
Wed Sep 24 22:40:24 CEST 2014


On Wed, Sep 24, 2014 at 11:55:38AM -0700, Dale Curtis wrote:
> Some Chrome users ( http://crbug.com/415542 ) are encountering content
> which requires CODEC_FLAG2_CHUNKS to decode without the following error:
> 
> http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/h264.c;hb=HEAD#l1917
> 
> We haven't enabled this flag globally in the past since it disables frame
> level threading:
> 
> http://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/pthread.c;hb=HEAD#l46
> 
> I have a couple questions on handling this type of content:
> 
> - Is the error returned truly an error or a warning? Ignoring it reveals
> decoding continues okay; though I have no idea if this is always true for
> chunked content.

it depends on how you see it

the decoder has as input 1 AU for each call, when the input is not a
AU thats more or less an error

for decoding the whole movie these instances of odd input are not
really errors in the case of this file


> 
> - Chrome currently only uses 2 threads for video decoding. I'll run the
> numbers soon, but generally, is frame level threading expected to be
> beneficial with only two threads?
> 
> Thanks in advance!
> 
> - dale
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-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many things microsoft did are stupid, but not doing something just because
microsoft did it is even more stupid. If everything ms did were stupid they
would be bankrupt already.
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