[FFmpeg-devel] [PATCH] lavc/videotoolboxenc: add hdr10, linear, hlg color transfer function for videotoolboxenc

[Dennis Mungai]

On Wed, Jul 10, 2019, 03:05 Aman Gupta <ffmpeg at tmm1.net> wrote:

> On Wed, Jun 26, 2019 at 4:25 AM <lance.lmwang at gmail.com> wrote:
>
> > From: Limin Wang <lance.lmwang at gmail.com>
> >
> > Below is the testing ffmpeg command for the setting:
> > ./ffmpeg -i input.ts -c:v hevc_videotoolbox -color_primaries bt2020
> > -colorspace bt2020_ncl -color_trc smpte2084 smpte2048.ts
> > ./ffmpeg -i input.ts -c:v hevc_videotoolbox -color_primaries bt2020
> > -colorspace bt2020_ncl -color_trc linear linear.ts
> > ./ffmpeg -i input.ts -c:v hevc_videotoolbox -color_primaries bt2020
> > -colorspace bt2020_ncl -color_trc arib-std-b67 hlg.ts
> >
>
> Patch looks reasonable to me. Will commit in a few days if no one else
> comments.
>
> Aman
>
>
> >
> > Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> > ---
> >  configure                    |  6 ++++++
> >  libavcodec/videotoolboxenc.c | 16 ++++++++++++++++
> >  2 files changed, 22 insertions(+)
> >
> > diff --git a/configure b/configure
> > index 7cea9d4d73..0a5e940c0c 100755
> > --- a/configure
> > +++ b/configure
> > @@ -2260,6 +2260,9 @@ TOOLCHAIN_FEATURES="
> >  TYPES_LIST="
> >      kCMVideoCodecType_HEVC
> >      kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange
> > +    kCVImageBufferTransferFunction_SMPTE_ST_2084_PQ
> > +    kCVImageBufferTransferFunction_ITU_R_2100_HLG
> > +    kCVImageBufferTransferFunction_Linear
> >      socklen_t
> >      struct_addrinfo
> >      struct_group_source_req
> > @@ -6044,6 +6047,9 @@ enabled videotoolbox && {
> >      check_lib coreservices CoreServices/CoreServices.h
> > UTGetOSTypeFromString "-framework CoreServices"
> >      check_func_headers CoreMedia/CMFormatDescription.h
> > kCMVideoCodecType_HEVC "-framework CoreMedia"
> >      check_func_headers CoreVideo/CVPixelBuffer.h
> > kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange "-framework CoreVideo"
> > +    check_func_headers CoreVideo/CVImageBuffer.h
> > kCVImageBufferTransferFunction_SMPTE_ST_2084_PQ "-framework CoreVideo"
> > +    check_func_headers CoreVideo/CVImageBuffer.h
> > kCVImageBufferTransferFunction_ITU_R_2100_HLG "-framework CoreVideo"
> > +    check_func_headers CoreVideo/CVImageBuffer.h
> > kCVImageBufferTransferFunction_Linear "-framework CoreVideo"
> >  }
> >
> >  check_struct "sys/time.h sys/resource.h" "struct rusage" ru_maxrss
> > diff --git a/libavcodec/videotoolboxenc.c b/libavcodec/videotoolboxenc.c
> > index f8ccdea52d..0dc6eb4cf4 100644
> > --- a/libavcodec/videotoolboxenc.c
> > +++ b/libavcodec/videotoolboxenc.c
> > @@ -915,6 +915,22 @@ static int get_cv_transfer_function(AVCodecContext
> > *avctx,
> >              *transfer_fnc =
> > kCVImageBufferTransferFunction_SMPTE_240M_1995;
> >              break;
> >
> > +#if HAVE_KCVIMAGEBUFFERTRANSFERFUNCTION_SMPTE_ST_2084_PQ
> > +        case AVCOL_TRC_SMPTE2084:
> > +            *transfer_fnc =
> > kCVImageBufferTransferFunction_SMPTE_ST_2084_PQ;
> > +            break;
> > +#endif
> > +#if HAVE_KCVIMAGEBUFFERTRANSFERFUNCTION_LINEAR
> > +        case AVCOL_TRC_LINEAR:
> > +            *transfer_fnc = kCVImageBufferTransferFunction_Linear;
> > +            break;
> > +#endif
> > +#if HAVE_KCVIMAGEBUFFERTRANSFERFUNCTION_ITU_R_2100_HLG
> > +        case AVCOL_TRC_ARIB_STD_B67:
> > +            *transfer_fnc =
> kCVImageBufferTransferFunction_ITU_R_2100_HLG;
> > +            break;
> > +#endif
> > +
> >          case AVCOL_TRC_GAMMA22:
> >              gamma = 2.2;
> >              *transfer_fnc = kCVImageBufferTransferFunction_UseGamma;
> > --
> > 2.21.0
> >
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> >
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>

A while back, a similar patch was rejected for NVENC (from the same author)
on the basis of such functionality not being suitably placed as an encoder
feature.

Looking back at other implementations, eg hevc_vaapi, the same is indeed
allowed, where SEI metadata retention for HDR is present.

To the OP: If the patch for NVENC were refactored in a manner similar to
this, abstracting details such as master display info for HDR (something
that was specifically flagged as not suitable as an encoder feature), it
might pass the patch review and be merged.

Are there specific limitations (as implemented) that block such a feature
in NVENC? Perhaps the initial patch with mastering display controls for HDR
was written that way to circumvent such a limitation.

Regards,

Dennis

>