[FFmpeg-devel] [PATCH v2 10/11] avcodec: add vvc metadata bsf

[Nuo Mi]

On Sat, Jan 9, 2021 at 11:11 PM Nuo Mi <nuomi2021 at gmail.com> wrote:

>
> Hi James,
> On Sat, Jan 9, 2021 at 10:53 PM James Almer <jamrial at gmail.com> wrote:
>
>> On 1/9/2021 4:34 AM, Nuo Mi wrote:
>> > use following command to test:
>> > ffmpeg -i in.bin  -c:v copy -bsf vvc_metadata -f vvc out.bin
>> >
>> > 79.11%(197/249) can bit match with original clips
>> > 6.83%(17/249) are not bit match, the original clips has redundant
>> emulation prevent bytes
>> > other all failed since vvdec failed to decode the first frame
>>
>> You don't (or shouldn't) need a decoder in order to do bitstream
>> filtering, since it works on packets (codec copy) and not frames.
>>
>> Since the decoder you submitted is, if committed, going to be external,
>> it will not be present in most libavcodec builds out there. This means
>> that you should ensure parsing of such files can succeed without a
>> decoder, so bsfs can run without it. If not possible already in the
>> state you wrote it in patch 8/11, it can be achieved by temporarily
>> setting some values in the parser until an internal decoder is
>> implemented.
>> For AV1 i had to set avctx dimensions and pixel format, both things i
>> removed once the internal decoder (as barebones as it is) was
>> introduced, since it's its job. I assume h266 will require the same.
>
> Thanks for suggestion. I will try it.
> I tried to disable hevc native decoder, and use hevc bsf only. It got the
> same error as vvc.
> Do we need fix this too?
>
We have set dimensions and format code in 8/11, but it still need decoder.
I will dig it more.

>
>
>
>
>> > ---
>> >   configure                      |   1 +
>> >   libavcodec/Makefile            |   1 +
>> >   libavcodec/bitstream_filters.c |   1 +
>> >   libavcodec/vvc_metadata_bsf.c  | 243 +++++++++++++++++++++++++++++++++
>> >   4 files changed, 246 insertions(+)
>> >   create mode 100644 libavcodec/vvc_metadata_bsf.c
>> >
>> > diff --git a/configure b/configure
>> > index 5ff743d9c2..b41f2af151 100755
>> > --- a/configure
>> > +++ b/configure
>> > @@ -3184,6 +3184,7 @@ mjpeg2jpeg_bsf_select="jpegtables"
>> >   mpeg2_metadata_bsf_select="cbs_mpeg2"
>> >   trace_headers_bsf_select="cbs"
>> >   vp9_metadata_bsf_select="cbs_vp9"
>> > +vvc_metadata_bsf_select="cbs_h266"
>>
>> For the sake of consistency, this bsf should be called h266_metadata and
>> not vcc_metadata, seeing the other two are h264 and h265 respectively.
>> It's part of what i suggested, but guess it got mixed in between the rest.
>>
> This is a funny part. Seems the filter name is hevc_metadata. But the
> class name is h265_metadata_bsf...
>
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>
>