Mark Thompson: > --- > libavcodec/Makefile | 2 +- > libavcodec/cbs_h265.c | 100 ++++++++++++++++++++++++++++++++++++++++++ > libavcodec/cbs_h265.h | 18 ++++++++ > 3 files changed, 119 insertions(+), 1 deletion(-) > create mode 100644 libavcodec/cbs_h265.c > > diff --git a/libavcodec/Makefile b/libavcodec/Makefile > index 6394694617..96dc1df343 100644 > --- a/libavcodec/Makefile > +++ b/libavcodec/Makefile > @@ -71,7 +71,7 @@ OBJS-$(CONFIG_CABAC) += cabac.o > OBJS-$(CONFIG_CBS) += cbs.o > OBJS-$(CONFIG_CBS_AV1) += cbs_av1.o > OBJS-$(CONFIG_CBS_H264) += cbs_h2645.o cbs_h264.o > h2645_parse.o > -OBJS-$(CONFIG_CBS_H265) += cbs_h2645.o h2645_parse.o > +OBJS-$(CONFIG_CBS_H265) += cbs_h2645.o cbs_h265.o > h2645_parse.o > OBJS-$(CONFIG_CBS_JPEG) += cbs_jpeg.o > OBJS-$(CONFIG_CBS_MPEG2) += cbs_mpeg2.o > OBJS-$(CONFIG_CBS_VP9) += cbs_vp9.o > diff --git a/libavcodec/cbs_h265.c b/libavcodec/cbs_h265.c > new file mode 100644 > index 0000000000..afbdd37896 > --- /dev/null > +++ b/libavcodec/cbs_h265.c > @@ -0,0 +1,100 @@ > +/* > + * This file is part of FFmpeg. > + * > + * FFmpeg is free software; you can redistribute it and/or > + * modify it under the terms of the GNU Lesser General Public > + * License as published by the Free Software Foundation; either > + * version 2.1 of the License, or (at your option) any later version. > + * > + * FFmpeg is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * Lesser General Public License for more details. > + * > + * You should have received a copy of the GNU Lesser General Public > + * License along with FFmpeg; if not, write to the Free Software > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 > USA > + */ > + > +#include "libavutil/mathematics.h" > +#include "libavutil/mastering_display_metadata.h" > + > +#include "cbs_h265.h" > + > + > +static uint32_t rescale_clip(AVRational value, uint32_t scale, uint32_t max) > +{ > + int64_t scaled = av_rescale(scale, value.num, value.den); > + return av_clip64(scaled, 0, max); > +} > + > +static uint32_t rescale_fraction(AVRational value, uint32_t max) > +{ > + return rescale_clip(value, max, max); > +} > + > +void > ff_cbs_h265_fill_sei_mastering_display(H265RawSEIMasteringDisplayColourVolume > *mdcv, > + const AVMasteringDisplayMetadata > *mdm) > +{ > + memset(mdcv, 0, sizeof(*mdcv)); > + > + if (mdm->has_primaries) { > + // The values in the metadata structure are fractions between 0 and > 1, > + // while the SEI message contains fixed-point values with an > increment > + // of 0.00002. So, scale up by 50000 to convert between them. > + > + for (int a = 0; a < 3; a++) { > + // The metadata structure stores this in RGB order, but the SEI > + // wants it in GBR order. > + static const uint8_t mapping[] = { 1, 2, 0 }; > + int b = mapping[a]; > + mdcv->display_primaries_x[a] = > + rescale_fraction(mdm->display_primaries[b][0], 50000); > + mdcv->display_primaries_y[a] = > + rescale_fraction(mdm->display_primaries[b][1], 50000);
Unfortunately the Mastering display colour volume SEI message semantics have been rewritten in the revision 06/19 of the H.265 standard. The old semantics for the x coordinate is only retained when the value is in the range 5..37000, for y it is 5..42000. Values outside these ranges are unknown/unspecified/specified by other specifications. So I suggest to clip it the values into these ranges. > + } > + > + mdcv->white_point_x = rescale_fraction(mdm->white_point[0], 50000); > + mdcv->white_point_y = rescale_fraction(mdm->white_point[1], 50000); The 5..37000/42000 ranges also apply to white_point_x/y. > + } > + > + if (mdm->has_luminance) { > + // Metadata are rational values in candelas per square metre, SEI > + // contains fixed point in units of 0.0001 candelas per square > + // metre. So scale up by 10000 to convert between them, and clip to > + // ensure that we don't overflow. > + > + mdcv->max_display_mastering_luminance = > + rescale_clip(mdm->max_luminance, 10000, UINT32_MAX); > + mdcv->min_display_mastering_luminance = > + rescale_clip(mdm->min_luminance, 10000, UINT32_MAX); > + The old semantics of these fields is only retained in the ranges 50000..100000000 and 1..50000. min == max == 50000 is forbidden. > + // The spec has a hard requirement that min is less than the max, > + // and the SEI-writing code enforces that. > + if (!(mdcv->min_display_mastering_luminance < > + mdcv->max_display_mastering_luminance)) { > + if (mdcv->max_display_mastering_luminance == UINT32_MAX) > + mdcv->min_display_mastering_luminance = > + mdcv->max_display_mastering_luminance - 1; > + else > + mdcv->max_display_mastering_luminance = > + mdcv->min_display_mastering_luminance + 1; > + } > + } else { > + mdcv->max_display_mastering_luminance = 1; max_display_mastering_luminance is no longer forbidden to be zero. In fact the spec mentions: "An example of the use of values outside the range for which semantics are specified in this Specification is that ANSI/CTA 861-G (2016) uses the value 0 for the nominal maximum display luminance of the mastering display to indicate that the nominal maximum display luminance of the mastering display is unknown." Obviously, the code for reading/writing the mastering display colour volume SEI needs to be updated, too. > + mdcv->min_display_mastering_luminance = 0; > + } > +} > + > +void > ff_cbs_h265_fill_sei_content_light_level(H265RawSEIContentLightLevelInfo *cll, > + const AVContentLightMetadata > *clm) > +{ > + memset(cll, 0, sizeof(*cll)); > + > + // Both the metadata and the SEI are in units of candelas per square > + // metre, so we only need to clip to ensure that they are in the valid > + // range. > + > + cll->max_content_light_level = av_clip_uintp2(clm->MaxCLL, 16); > + cll->max_pic_average_light_level = av_clip_uintp2(clm->MaxFALL, 16); > +} This one seems to be fine. > diff --git a/libavcodec/cbs_h265.h b/libavcodec/cbs_h265.h > index c14cd4cd66..999353f607 100644 > --- a/libavcodec/cbs_h265.h > +++ b/libavcodec/cbs_h265.h > @@ -747,4 +747,22 @@ typedef struct CodedBitstreamH265Context { > } CodedBitstreamH265Context; > > > +struct AVMasteringDisplayMetadata; > +struct AVContentLightMetadata; > + > +/** > + * Fill an SEI Mastering Display Colour Volume structure with values derived > + * from the AVMasteringDisplayMetadata side-data structure. > + */ > +void > ff_cbs_h265_fill_sei_mastering_display(H265RawSEIMasteringDisplayColourVolume > *mdcv, > + const struct > AVMasteringDisplayMetadata *mdm); > + > +/** > + * Fill an SEI Content Light Level Info structure with values derived from > + * the AVContentLightMetadata side-data structure. > + */ > +void > ff_cbs_h265_fill_sei_content_light_level(H265RawSEIContentLightLevelInfo *cll, > + const struct > AVContentLightMetadata *clm); > + > + > #endif /* AVCODEC_CBS_H265_H */ > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".