[FFmpeg-devel] [PATCH] libavcodec:add dxva2 decoder for h264, mpeg2, vc1.wmv3

Wei Gao highgod0401 at gmail.com
Wed Jan 23 09:15:44 CET 2013


Hi,Hendrik

- The handling of the parser in the h264 part of check_format looks
quite broken, i have no clue what its supposed to do? You have no data
to parse there.

This parser, I reference vda process for h264 to check the format, I think
it just get the H264Context, using av_parser_parse2, and then check the
format.

- get_mpeg2_video_format assumes there always is extradata, which may
not be the case, and should be checked.

I just check whether the extra data is exist. Also I want to ask a question
that is the chroma_format always stored in the ext sequence header?

The attachment is the patch I modified.

Thanks

Best regards


2013/1/22 Hendrik Leppkes <h.leppkes at gmail.com>

> Hi,
>
> here is some more comments:
>
> - Why are all the functions in dxva2_wrapper.h public (av_* prefix)?
> They should be private with the ff_ prefix. None of these functions or
> headers should be public (or have any need to be)
> - Makefile: CONFIG_DXVA2 does NOT need the new files, so they should
> not be included there. They should only be included if the new
> decoder(s) are selected.
> - get_mpeg2_video_format assumes there always is extradata, which may
> not be the case, and should be checked.
> - The handling of the parser in the h264 part of check_format looks
> quite broken, i have no clue what its supposed to do? You have no data
> to parse there.
> - Additionally, your check is incomplete, h264 8-bit 4:2:0 could still
> be incompatible with hardware decoders, you also need to check for the
> profile, only baseline/main/high is supported by current hardware, and
> 8-bit 4:2:0 could still be lossless, for example.
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>
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