[FFmpeg-devel] [PATCH v3 2/2] lavc/vaapi_encode_h265: Set general_*_constriaint flags with profile

Wang, Fei W fei.w.wang at intel.com
Tue Apr 2 08:18:08 EEST 2024


On Mon, 2024-04-01 at 21:02 +0100, Mark Thompson wrote:
> On 20/03/2024 08:44, Wang, Fei W wrote:
> > On Mon, 2024-03-18 at 21:22 +0000, Mark Thompson wrote:
> > > On 18/03/2024 04:21, fei.w.wang-at-intel.com at ffmpeg.org wrote:
> > > > From: Fei Wang <fei.w.wang at intel.com>
> > > > 
> > > > According to Table A.2 in spec.
> > > > 
> > > > Signed-off-by: Fei Wang <fei.w.wang at intel.com>
> > > > ---
> > > >    libavcodec/vaapi_encode_h265.c | 176
> > > > +++++++++++++++++++++++-----
> > > > -----
> > > >    1 file changed, 123 insertions(+), 53 deletions(-)
> > > > 
> > > > diff --git a/libavcodec/vaapi_encode_h265.c
> > > > b/libavcodec/vaapi_encode_h265.c
> > > > index 43755e2188..5ed317ce11 100644
> > > > --- a/libavcodec/vaapi_encode_h265.c
> > > > +++ b/libavcodec/vaapi_encode_h265.c
> > > > @@ -258,6 +258,124 @@ fail:
> > > >        return err;
> > > >    }
> > > >    
> > > > +static int vaapi_encode_h265_init_ptl(AVCodecContext *avctx)
> > > > +{
> > > > +    VAAPIEncodeContext      *ctx = avctx->priv_data;
> > > > +    VAAPIEncodeH265Context *priv = avctx->priv_data;
> > > > +    H265RawVPS              *vps = &priv->raw_vps;
> > > > +    H265RawProfileTierLevel *ptl = &vps->profile_tier_level;
> > > > +
> > > > +    ptl->general_profile_space = 0;
> > > > +    ptl->general_profile_idc   = avctx->profile;
> > > > +    ptl->general_tier_flag     = priv->tier;
> > > > +
> > > > +    ptl->general_profile_compatibility_flag[ptl-
> > > > > general_profile_idc] = 1;
> > > > +
> > > > +    if (ptl->general_profile_compatibility_flag[1])
> > > > +        ptl->general_profile_compatibility_flag[2] = 1;
> > > > +    if (ptl->general_profile_compatibility_flag[3]) {
> > > > +        ptl->general_profile_compatibility_flag[1] = 1;
> > > > +        ptl->general_profile_compatibility_flag[2] = 1;
> > > > +    }
> > > > +
> > > > +    ptl->general_progressive_source_flag    = 1;
> > > > +    ptl->general_interlaced_source_flag     = 0;
> > > > +    ptl->general_non_packed_constraint_flag = 1;
> > > > +    ptl->general_frame_only_constraint_flag = 1;
> > > > +
> > > > +    if (avctx->profile >= 4) {
> > > > +        ptl->general_intra_constraint_flag            = ctx-
> > > > > gop_size == 1;
> > > > +        ptl->general_one_picture_only_constraint_flag = 0;
> > > > +        ptl->general_lower_bit_rate_constraint_flag   = 1;
> > > > +        ptl->general_max_14bit_constraint_flag        = 0;
> > > > +
> > > > +        switch (ctx->va_profile) {
> > > > +#if VA_CHECK_VERSION(1, 2, 0)
> > > > +        case VAProfileHEVCMain12:
> > > > +            // Main 12
> > > > +            ptl->general_max_12bit_constraint_flag      = 1;
> > > > +            ptl->general_max_10bit_constraint_flag      = 0;
> > > > +            ptl->general_max_8bit_constraint_flag       = 0;
> > > > +            ptl->general_max_422chroma_constraint_flag  = 1;
> > > > +            ptl->general_max_420chroma_constraint_flag  = 1;
> > > > +            ptl->general_max_monochrome_constraint_flag = 0;
> > > > +            break;
> > > > +        case VAProfileHEVCMain422_10:
> > > > +            // Main 4:2:2 10
> > > > +            ptl->general_max_12bit_constraint_flag      = 1;
> > > > +            ptl->general_max_10bit_constraint_flag      = 1;
> > > > +            ptl->general_max_8bit_constraint_flag       = 0;
> > > > +            ptl->general_max_422chroma_constraint_flag  = 1;
> > > > +            ptl->general_max_420chroma_constraint_flag  = 0;
> > > > +            ptl->general_max_monochrome_constraint_flag = 0;
> > > > +            break;
> > > > +        case VAProfileHEVCMain422_12:
> > > > +            // Main 4:2:2 12
> > > > +            ptl->general_max_12bit_constraint_flag      = 1;
> > > > +            ptl->general_max_10bit_constraint_flag      = 0;
> > > > +            ptl->general_max_8bit_constraint_flag       = 0;
> > > > +            ptl->general_max_422chroma_constraint_flag  = 1;
> > > > +            ptl->general_max_420chroma_constraint_flag  = 0;
> > > > +            ptl->general_max_monochrome_constraint_flag = 0;
> > > > +            break;
> > > > +        case VAProfileHEVCMain444:
> > > > +            // Main 4:4:4
> > > > +            ptl->general_max_12bit_constraint_flag      = 1;
> > > > +            ptl->general_max_10bit_constraint_flag      = 1;
> > > > +            ptl->general_max_8bit_constraint_flag       = 1;
> > > > +            ptl->general_max_422chroma_constraint_flag  = 0;
> > > > +            ptl->general_max_420chroma_constraint_flag  = 0;
> > > > +            ptl->general_max_monochrome_constraint_flag = 0;
> > > > +            break;
> > > > +        case VAProfileHEVCMain444_10:
> > > > +            // Main 4:4:4 10
> > > > +            ptl->general_max_12bit_constraint_flag      = 1;
> > > > +            ptl->general_max_10bit_constraint_flag      = 1;
> > > > +            ptl->general_max_8bit_constraint_flag       = 0;
> > > > +            ptl->general_max_422chroma_constraint_flag  = 0;
> > > > +            ptl->general_max_420chroma_constraint_flag  = 0;
> > > > +            ptl->general_max_monochrome_constraint_flag = 0;
> > > > +            break;
> > > > +        case VAProfileHEVCMain444_12:
> > > > +            // Main 4:4:4 12
> > > > +            ptl->general_max_12bit_constraint_flag      = 1;
> > > > +            ptl->general_max_10bit_constraint_flag      = 0;
> > > > +            ptl->general_max_8bit_constraint_flag       = 0;
> > > > +            ptl->general_max_422chroma_constraint_flag  = 0;
> > > > +            ptl->general_max_420chroma_constraint_flag  = 0;
> > > > +            ptl->general_max_monochrome_constraint_flag = 0;
> > > > +            break;
> > > > +#endif
> > > > +        default:
> > > > +            av_log(avctx, AV_LOG_ERROR, "Unknown profile to
> > > > init
> > > > PTL.\n");
> > > > +            return AVERROR(EINVAL);
> > > > +        }
> > > > +    }
> > > 
> > > Why is this an improvement over the current code which sets the
> > > constraint flags based on the actual content of the stream?
> > > 
> > > Note the requirement in A.3.5 for decoder support:
> > > 
> > > general_profile_idc is equal to 4 or
> > > general_profile_compatibility_flag[ 4 ] is equal to 1 for the
> > > bitstream, and
> > > the value of each constraint flag listed in Table A.2 is greater
> > > than
> > > or equal to the value(s) specified in the row
> > > of Table A.2 for the format range extensions profile for which
> > > the
> > > decoder conformance is evaluated.
> > > 
> > > which says that decoders must be able to support streams which
> > > set
> > > additional constraint flags beyond those which are specified for
> > > a
> > > particular profile (in particular, an 8-bit 4:2:2 stream must be
> > > decodable by any decoder supporting either "Main 4:2:2 10" or
> > > "Main
> > > 4:4:4", so ideally it shouldn't be marked to require one of those
> > > in
> > > particular).
> > 
> > That's a capability request for decoder. For encoder side, I'd
> > prefer
> > to use the most typical values. The constraint flags in Table
> > A.2/3/5
> > are strictly checked to get rext profile in ff_h265_get_profile(),
> > and
> > seems the constraint flags is the only way to distinguish profiles
> > in
> > rext(all the rext profiles shares same general_profile_idc or
> > general_profile_compatibility_flag[ 4 ]).
> 
> Hmm.  I was missing that the VAAPI decoder has fixed matching - it
> only accepts things which exactly match the hull of each profile, not
> ones inside it which are compatible.  That seems worth fixing.
> 
> Do other decoder implementations do the same thing with strict
> matching?  libavcodec's software decoder doesn't - the profile isn't
> really relevant to it.  nvdec doesn't obviously do anything there
> either because it accepts all rext streams, though presumably some of
> them fail later.

HEVC bsf also checked them strictly in process metadata(called by
ff_h265_guess_level).

And VQ Analyzer(a video stream analysis tool 
https://vicuesoft.com/vq-analyzer/) also report unknown profile if no
this fix.

Thanks
Fei

> 
> Thanks,
> 
> - Mark
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