[FFmpeg-devel] [PATCH 17/18] cbs_h265: Add functions to turn HDR metadata into SEI
Mark Thompson
sw at jkqxz.net
Thu Oct 3 02:04:52 EEST 2019
---
With intent to add some sort of support for this in H.265 metadata, though it's not in this set.
Is there any thought on what a human-usable text serialisation of AVMasteringDisplayMetadata should look like? Ideally it wants to be something which would require no escaping when using it on the command-line. (This is relevant to video filters as well.)
libavcodec/Makefile | 2 +-
libavcodec/cbs_h265.c | 94 +++++++++++++++++++++++++++++++++++++++++++
libavcodec/cbs_h265.h | 18 +++++++++
3 files changed, 113 insertions(+), 1 deletion(-)
create mode 100644 libavcodec/cbs_h265.c
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 86e512b605..d383d4a539 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -65,7 +65,7 @@ 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..b4850bd565
--- /dev/null
+++ b/libavcodec/cbs_h265.c
@@ -0,0 +1,94 @@
+/*
+ * 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 unsigned int rescale(AVRational value, unsigned int max)
+{
+ int64_t scaled = av_rescale(max, value.num, value.den);
+ return av_clip(scaled, 0, 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 are rationals in the range [0, 1],
+ // while the SEI structure 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 stores this in RGB order, but the SEI wants it
+ // in GBR order.
+ int b = (a + 1) % 3;
+ mdcv->display_primaries_x[a] =
+ rescale(mdm->display_primaries[b][0], 50000);
+ mdcv->display_primaries_y[a] =
+ rescale(mdm->display_primaries[b][1], 50000);
+ }
+
+ mdcv->white_point_x = rescale(mdm->white_point[0], 50000);
+ mdcv->white_point_y = rescale(mdm->white_point[1], 50000);
+ }
+
+ 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.
+
+ mdcv->max_display_mastering_luminance =
+ rescale(mdm->max_luminance, 10000);
+ mdcv->min_display_mastering_luminance =
+ rescale(mdm->min_luminance, 10000);
+
+ // 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 == 10000)
+ 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;
+ 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->MaxCLL, 16);
+}
diff --git a/libavcodec/cbs_h265.h b/libavcodec/cbs_h265.h
index f5eb5af5b2..793675ad41 100644
--- a/libavcodec/cbs_h265.h
+++ b/libavcodec/cbs_h265.h
@@ -746,4 +746,22 @@ 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 */
--
2.20.1
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