[FFmpeg-devel] [PATCH 1/6] avutil: add an API to handle 3D Reference Displays Information
James Almer
jamrial at gmail.com
Fri Jan 31 16:00:15 EET 2025
As defined in section G.14.3.2.3 of ITU-T H.265, it's required for proper signaling of
MV-HEVC.
Signed-off-by: James Almer <jamrial at gmail.com>
---
libavutil/Makefile | 2 +
libavutil/tdrdi.c | 35 ++++++++++++
libavutil/tdrdi.h | 129 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 166 insertions(+)
create mode 100644 libavutil/tdrdi.c
create mode 100644 libavutil/tdrdi.h
diff --git a/libavutil/Makefile b/libavutil/Makefile
index f8031815bd..a9a98d18a5 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -84,6 +84,7 @@ HEADERS = adler32.h \
sha512.h \
spherical.h \
stereo3d.h \
+ tdrdi.h \
threadmessage.h \
time.h \
timecode.h \
@@ -176,6 +177,7 @@ OBJS = adler32.o \
slicethread.o \
spherical.o \
stereo3d.o \
+ tdrdi.o \
threadmessage.o \
time.o \
timecode.o \
diff --git a/libavutil/tdrdi.c b/libavutil/tdrdi.c
new file mode 100644
index 0000000000..144f31db05
--- /dev/null
+++ b/libavutil/tdrdi.c
@@ -0,0 +1,35 @@
+/*
+ * 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 <stddef.h>
+#include <stdint.h>
+
+#include "mem.h"
+#include "tdrdi.h"
+
+AV3DReferenceDisplaysInfo *av_tdrdi_alloc(size_t *size)
+{
+ AV3DReferenceDisplaysInfo *tdrdi = av_mallocz(sizeof(AV3DReferenceDisplaysInfo));
+ if (!tdrdi)
+ return NULL;
+
+ if (size)
+ *size = sizeof(*tdrdi);
+
+ return tdrdi;
+}
diff --git a/libavutil/tdrdi.h b/libavutil/tdrdi.h
new file mode 100644
index 0000000000..896873374c
--- /dev/null
+++ b/libavutil/tdrdi.h
@@ -0,0 +1,129 @@
+/*
+ * 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
+ */
+
+/**
+ * @file
+ * @ingroup lavu_video_spherical
+ * Spherical video
+ */
+
+#ifndef AVUTIL_TDRDI_H
+#define AVUTIL_TDRDI_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/**
+ * @defgroup lavu_video_reference_displays_info 3D Reference Displays Information
+ * @ingroup lavu_video
+ *
+ * @{
+ */
+
+#define AV_TDRDI_MAX_NUM_REF_DISPLAY 32
+/**
+ * This structure describes information about the reference display width(s) and reference
+ * viewing distance(s) as well as information about the corresponding reference stereo pair(s)
+ * See section G.14.3.2.3 of ITU-T H.265 for more information.
+ *
+ * @note The struct must be allocated with av_tdrdi_alloc() and
+ * its size is not a part of the public ABI.
+ */
+typedef struct AV3DReferenceDisplaysInfo {
+ /**
+ * The exponent of the maximum allowable truncation error for
+ * {exponent,mantissa}_ref_display_width as given by 2 ^ (-prec_ref_display_width).
+ */
+ uint8_t prec_ref_display_width;
+
+ /**
+ * A flag to indicate the presence of reference viewing distance.
+ * If false, the values of prec_ref_viewing_dist, exponent_ref_viewing_distance,
+ * and mantissa_ref_viewing_distance are undefined.
+ */
+ uint8_t ref_viewing_distance_flag;
+
+ /**
+ * The exponent of the maximum allowable truncation error for
+ * {exponent,mantissa}_ref_viewing_distance as given by 2 ^ (-prec_ref_viewing_dist).
+ * The value of prec_ref_viewing_dist shall be in the range of 0 to 31, inclusive.
+ */
+ uint8_t prec_ref_viewing_dist;
+
+ /**
+ * The number of reference displays that are signalled in this struct.
+ * Allowed range is 1 to 32, inclusive.
+ */
+ uint8_t num_ref_displays;
+
+ /**
+ * The ViewId of the left view of a stereo pair corresponding to the n-th reference display.
+ */
+ uint16_t left_view_id[AV_TDRDI_MAX_NUM_REF_DISPLAY];
+
+ /**
+ * The ViewId of the left view of a stereo pair corresponding to the n-th reference display.
+ */
+ uint16_t right_view_id[AV_TDRDI_MAX_NUM_REF_DISPLAY];
+
+ /**
+ * The exponent part of the reference display width of the n-th reference display.
+ */
+ uint8_t exponent_ref_display_width[AV_TDRDI_MAX_NUM_REF_DISPLAY];
+
+ /**
+ * The mantissa part of the reference display width of the n-th reference display.
+ */
+ uint8_t mantissa_ref_display_width[AV_TDRDI_MAX_NUM_REF_DISPLAY];
+
+ /**
+ * Tthe exponent part of the reference viewing distance of the n-th reference display.
+ */
+ uint8_t exponent_ref_viewing_distance[AV_TDRDI_MAX_NUM_REF_DISPLAY];
+
+ /**
+ * The mantissa part of the reference viewing distance of the n-th reference display.
+ */
+ uint8_t mantissa_ref_viewing_distance[AV_TDRDI_MAX_NUM_REF_DISPLAY];
+
+ /**
+ * An array of flags to indicates that the information about additional horizontal shift of
+ * the left and right views for the n-th reference display is present.
+ */
+ uint8_t additional_shift_present_flag[AV_TDRDI_MAX_NUM_REF_DISPLAY];
+
+ /**
+ * The recommended additional horizontal shift for a stereo pair corresponding to the n-th
+ * reference baseline and the n-th reference display.
+ */
+ int16_t num_sample_shift[AV_TDRDI_MAX_NUM_REF_DISPLAY];
+} AV3DReferenceDisplaysInfo;
+
+/**
+ * Allocate a AV3DReferenceDisplaysInfo structure and initialize its fields to default
+ * values.
+ *
+ * @return the newly allocated struct or NULL on failure
+ */
+AV3DReferenceDisplaysInfo *av_tdrdi_alloc(size_t *size);
+
+/**
+ * @}
+ */
+
+#endif /* AVUTIL_TDRDI_H */
--
2.48.1
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