[FFmpeg-devel] [PATCH v2 3/4] lavc: Implement Dolby Vision RPU parsing
Niklas Haas
ffmpeg at haasn.xyz
Wed Dec 8 12:12:36 EET 2021
From: Niklas Haas <git at haasn.dev>
Based on a mixture of guesswork, partial documentation in patents, and
reverse engineering of real-world samples. Confirmed working for all the
samples I've thrown at it.
Contains some annoying machinery to persist these values in between
frames, which is needed in theory even though I've never actually seen a
sample that relies on it in practice. May or may not work.
Notable omissions:
- CRC32 verificaiton. This is based on the MPEG2 CRC32 type, which does
not seem to be implemented in lavc. (And I don't care enough to do so)
- Linear interpolation support. Nothing documents this (beyond its
existence) and no samples use it, so impossible to implement.
- All of the extension metadata blocks, but these contain values that
are basically congruent with ST2094, HDR10, or other existing forms of
side data, so I will defer parsing/attaching them to a future commit.
Heavily influenced by https://github.com/quietvoid/dovi_tool
Documentation drawn from US Patent 10,701,399 B2 and ETSI GS CCM 001
Signed-off-by: Niklas Haas <git at haasn.dev>
---
libavcodec/Makefile | 1 +
libavcodec/dovi.c | 369 ++++++++++++++++++++++++++++++++++++++++++++
libavcodec/dovi.h | 62 ++++++++
3 files changed, 432 insertions(+)
create mode 100644 libavcodec/dovi.c
create mode 100644 libavcodec/dovi.h
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 4122a9b144..c327e0d764 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -40,6 +40,7 @@ OBJS = ac3_parser.o \
d3d11va.o \
decode.o \
dirac.o \
+ dovi.o \
dv_profile.o \
encode.o \
imgconvert.o \
diff --git a/libavcodec/dovi.c b/libavcodec/dovi.c
new file mode 100644
index 0000000000..7e90092f0d
--- /dev/null
+++ b/libavcodec/dovi.c
@@ -0,0 +1,369 @@
+/*
+ * Dolby Vision RPU decoder
+ *
+ * Copyright (C) 2021 Jan Ekström
+ * Copyright (C) 2021 Niklas Haas
+ *
+ * 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 "dovi.h"
+#include "golomb.h"
+#include "get_bits.h"
+
+enum {
+ RPU_COEFF_FIXED = 0,
+ RPU_COEFF_FLOAT = 1,
+};
+
+/**
+ * Private contents of vdr_ref.
+ */
+typedef struct DOVIVdrRef {
+ AVDOVIDataMapping mapping;
+ AVDOVIColorMetadata color;
+} DOVIVdrRef;
+
+void ff_dovi_ctx_unref(DOVIContext *s)
+{
+ for (int i = 0; i < DOVI_MAX_DM_ID; i++)
+ av_buffer_unref(&s->vdr_ref[i]);
+
+ /* Preserve the AVCodecContext explicitly, reset everything else */
+ *s = (DOVIContext) {
+ .avctx = s->avctx,
+ };
+}
+
+int ff_dovi_ctx_replace(DOVIContext *s, const DOVIContext *s0)
+{
+ int ret;
+ for (int i = 0; i < DOVI_MAX_DM_ID; i++) {
+ if ((ret = av_buffer_replace(&s->vdr_ref[i], s0->vdr_ref[i])) < 0) {
+ s->mapping = NULL; /* sanity */
+ s->color = NULL;
+ return ret;
+ }
+ }
+
+ s->mapping = s0->mapping;
+ s->color = s0->color;
+ return 0;
+}
+
+static inline uint64_t get_ue_coef(GetBitContext *gb, const AVDOVIRpuDataHeader *hdr)
+{
+ uint64_t ipart;
+ union { uint32_t u32; float f32; } fpart;
+
+ switch (hdr->coef_data_type) {
+ case RPU_COEFF_FIXED:
+ ipart = get_ue_golomb_long(gb);
+ fpart.u32 = get_bits_long(gb, hdr->coef_log2_denom);
+ return (ipart << hdr->coef_log2_denom) + fpart.u32;
+
+ case RPU_COEFF_FLOAT:
+ fpart.u32 = get_bits_long(gb, 32);
+ return fpart.f32 * (1 << hdr->coef_log2_denom);
+ }
+
+ return 0; /* unreachable */
+}
+
+static inline int64_t get_se_coef(GetBitContext *gb, const AVDOVIRpuDataHeader *hdr)
+{
+ int64_t ipart;
+ union { uint32_t u32; float f32; } fpart;
+
+ switch (hdr->coef_data_type) {
+ case RPU_COEFF_FIXED:
+ ipart = get_se_golomb_long(gb);
+ fpart.u32 = get_bits_long(gb, hdr->coef_log2_denom);
+ return (ipart << hdr->coef_log2_denom) + fpart.u32;
+
+ case RPU_COEFF_FLOAT:
+ fpart.u32 = get_bits_long(gb, 32);
+ return fpart.f32 * (1 << hdr->coef_log2_denom);
+ }
+
+ return 0; /* unreachable */
+}
+
+#define VALIDATE(VAR, MIN, MAX) \
+ do { \
+ if (VAR < MIN || VAR > MAX) { \
+ av_log(s->avctx, AV_LOG_ERROR, "RPU validation failed: " \
+ #MIN" <= "#VAR" = %d <= "#MAX"\n", (int) VAR); \
+ goto fail; \
+ } \
+ } while (0)
+
+int ff_dovi_rpu_parse(DOVIContext *s, const uint8_t *rpu, size_t rpu_size)
+{
+ AVDOVIRpuDataHeader *hdr = &s->header;
+ GetBitContext *gb = &(GetBitContext){0};
+ DOVIVdrRef *vdr;
+ int ret;
+
+ uint8_t nal_prefix;
+ uint8_t rpu_type;
+ uint8_t vdr_seq_info_present;
+ uint8_t vdr_dm_metadata_present;
+ uint8_t use_prev_vdr_rpu;
+ uint8_t use_nlq;
+ if ((ret = init_get_bits8(gb, rpu, rpu_size)) < 0)
+ return ret;
+
+ /* RPU header, common values */
+ nal_prefix = get_bits(gb, 8);
+ VALIDATE(nal_prefix, 25, 25);
+ rpu_type = get_bits(gb, 6);
+ if (rpu_type != 2) {
+ av_log(s->avctx, AV_LOG_WARNING, "Unrecognized RPU type "
+ "%"PRIu8", ignoring\n", rpu_type);
+ return 0;
+ }
+
+ hdr->rpu_type = rpu_type;
+ hdr->rpu_format = get_bits(gb, 11);
+
+ /* Values specific to RPU type 2 */
+ hdr->vdr_rpu_profile = get_bits(gb, 4);
+ hdr->vdr_rpu_level = get_bits(gb, 4);
+
+ vdr_seq_info_present = get_bits1(gb);
+ if (vdr_seq_info_present) {
+ hdr->chroma_resampling_explicit_filter_flag = get_bits1(gb);
+ hdr->coef_data_type = get_bits(gb, 2);
+ VALIDATE(hdr->coef_data_type, RPU_COEFF_FIXED, RPU_COEFF_FLOAT);
+ switch (hdr->coef_data_type) {
+ case RPU_COEFF_FIXED:
+ hdr->coef_log2_denom = get_ue_golomb(gb);
+ VALIDATE(hdr->coef_log2_denom, 13, 32);
+ break;
+ case RPU_COEFF_FLOAT:
+ hdr->coef_log2_denom = 32; /* arbitrary, choose maximum precision */
+ break;
+ }
+
+ hdr->vdr_rpu_normalized_idc = get_bits(gb, 2);
+ hdr->bl_video_full_range_flag = get_bits1(gb);
+
+ if ((hdr->rpu_format & 0x700) == 0) {
+ int bl_bit_depth_minus8 = get_ue_golomb_31(gb);
+ int el_bit_depth_minus8 = get_ue_golomb_31(gb);
+ int vdr_bit_depth_minus8 = get_ue_golomb_31(gb);
+ VALIDATE(bl_bit_depth_minus8, 0, 8);
+ VALIDATE(el_bit_depth_minus8, 0, 8);
+ VALIDATE(vdr_bit_depth_minus8, 0, 8);
+ hdr->bl_bit_depth = bl_bit_depth_minus8 + 8;
+ hdr->el_bit_depth = el_bit_depth_minus8 + 8;
+ hdr->vdr_bit_depth = vdr_bit_depth_minus8 + 8;
+ hdr->spatial_resampling_filter_flag = get_bits1(gb);
+ skip_bits(gb, 3); /* reserved_zero_3bits */
+ hdr->el_spatial_resampling_filter_flag = get_bits1(gb);
+ hdr->disable_residual_flag = get_bits1(gb);
+ }
+ }
+
+ if (!hdr->bl_bit_depth) {
+ av_log(s->avctx, AV_LOG_ERROR, "Missing RPU VDR sequence info?\n");
+ goto fail;
+ }
+
+ vdr_dm_metadata_present = get_bits1(gb);
+ use_prev_vdr_rpu = get_bits1(gb);
+ use_nlq = (hdr->rpu_format & 0x700) == 0 && !hdr->disable_residual_flag;
+ if (av_dovi_profile(hdr) == 5 && use_nlq) {
+ av_log(s->avctx, AV_LOG_ERROR, "Profile 5 RPUs should not use NLQ\n");
+ goto fail;
+ }
+
+ if (use_prev_vdr_rpu) {
+ int prev_vdr_rpu_id = get_ue_golomb_31(gb);
+ VALIDATE(prev_vdr_rpu_id, 0, DOVI_MAX_DM_ID);
+ if (!s->vdr_ref[prev_vdr_rpu_id]) {
+ av_log(s->avctx, AV_LOG_ERROR, "Unknown previous RPU ID: %u\n",
+ prev_vdr_rpu_id);
+ goto fail;
+ }
+ vdr = (DOVIVdrRef *) s->vdr_ref[prev_vdr_rpu_id]->data;
+ s->mapping = &vdr->mapping;
+ } else {
+ int vdr_rpu_id = get_ue_golomb_31(gb);
+ VALIDATE(vdr_rpu_id, 0, DOVI_MAX_DM_ID);
+ if (!s->vdr_ref[vdr_rpu_id]) {
+ s->vdr_ref[vdr_rpu_id] = av_buffer_allocz(sizeof(DOVIVdrRef));
+ if (!s->vdr_ref[vdr_rpu_id])
+ return AVERROR(ENOMEM);
+ }
+
+ vdr = (DOVIVdrRef *) s->vdr_ref[vdr_rpu_id]->data;
+ s->mapping = &vdr->mapping;
+ vdr->mapping = (AVDOVIDataMapping) {
+ .vdr_rpu_id = vdr_rpu_id,
+ .mapping_color_space = get_ue_golomb_31(gb),
+ .mapping_chroma_format_idc = get_ue_golomb_31(gb),
+ };
+
+ for (int c = 0; c < 3; c++) {
+ AVDOVIReshapingCurve *curve = &vdr->mapping.curves[c];
+ int num_pivots_minus_2 = get_ue_golomb_31(gb);
+ int pivot = 0;
+
+ VALIDATE(num_pivots_minus_2, 0, FF_DOVI_MAX_PIECES - 1);
+ curve->num_pivots = num_pivots_minus_2 + 2;
+ for (int i = 0; i < curve->num_pivots; i++) {
+ pivot += get_bits(gb, hdr->bl_bit_depth);
+ curve->pivots[i] = av_clip_uint16(pivot);
+ }
+ }
+
+ if (use_nlq) {
+ vdr->mapping.nlq_method_idc = get_bits(gb, 3);
+ /**
+ * The patent mentions another legal value, NLQ_MU_LAW, but it's
+ * not documented anywhere how to parse or apply that type of NLQ.
+ */
+ VALIDATE(vdr->mapping.nlq_method_idc, 0, AV_DOVI_NLQ_LINEAR_DZ);
+ } else {
+ vdr->mapping.nlq_method_idc = AV_DOVI_NLQ_NONE;
+ }
+
+ vdr->mapping.num_x_partitions = get_ue_golomb_long(gb) + 1;
+ vdr->mapping.num_y_partitions = get_ue_golomb_long(gb) + 1;
+ /* End of rpu_data_header(), start of vdr_rpu_data_payload() */
+
+ for (int c = 0; c < 3; c++) {
+ AVDOVIReshapingCurve *curve = &vdr->mapping.curves[c];
+ for (int i = 0; i < curve->num_pivots - 1; i++) {
+ int mapping_idc = get_ue_golomb_31(gb);
+ VALIDATE(mapping_idc, 0, 1);
+ curve->mapping_idc[i] = mapping_idc;
+ switch (mapping_idc) {
+ case AV_DOVI_MAPPING_POLYNOMIAL: {
+ int poly_order_minus1 = get_ue_golomb_31(gb);
+ VALIDATE(poly_order_minus1, 0, 1);
+ curve->poly_order[i] = poly_order_minus1 + 1;
+ if (poly_order_minus1 == 0) {
+ int linear_interp_flag = get_bits1(gb);
+ if (linear_interp_flag) {
+ /* lack of documentation/samples */
+ av_log(s->avctx, AV_LOG_WARNING, "Linear "
+ "interpolation is unimplemented, please "
+ "open a bug report with the sample.\n");
+ ff_dovi_ctx_unref(s);
+ return AVERROR_PATCHWELCOME;
+ }
+ }
+ for (int k = 0; k <= curve->poly_order[i]; k++)
+ curve->poly_coef[i][k] = get_se_coef(gb, hdr);
+ break;
+ }
+ case AV_DOVI_MAPPING_MMR: {
+ int mmr_order_minus1 = get_bits(gb, 2);
+ VALIDATE(mmr_order_minus1, 0, 2);
+ curve->mmr_order[i] = mmr_order_minus1 + 1;
+ curve->mmr_constant[i] = get_se_coef(gb, hdr);
+ for (int j = 0; j < curve->mmr_order[i]; j++) {
+ for (int k = 0; k < 7; k++)
+ curve->mmr_coef[i][j][k] = get_se_coef(gb, hdr);
+ }
+ break;
+ }
+ }
+ }
+ }
+
+ if (use_nlq) {
+ for (int c = 0; c < 3; c++) {
+ AVDOVINLQParams *nlq = &vdr->mapping.nlq[c];
+ nlq->nlq_offset = get_bits(gb, hdr->el_bit_depth);
+ nlq->vdr_in_max = get_ue_coef(gb, hdr);
+ switch (vdr->mapping.nlq_method_idc) {
+ case AV_DOVI_NLQ_LINEAR_DZ:
+ nlq->linear_deadzone_slope = get_ue_coef(gb, hdr);
+ nlq->linear_deadzone_threshold = get_ue_coef(gb, hdr);
+ break;
+ }
+ }
+ }
+ }
+
+ if (vdr_dm_metadata_present) {
+ AVDOVIColorMetadata *color;
+ int affected_dm_id = get_ue_golomb_31(gb);
+ int current_dm_id = get_ue_golomb_31(gb);
+ VALIDATE(affected_dm_id, 0, DOVI_MAX_DM_ID);
+ VALIDATE(current_dm_id, 0, DOVI_MAX_DM_ID);
+ if (!s->vdr_ref[affected_dm_id]) {
+ s->vdr_ref[affected_dm_id] = av_buffer_allocz(sizeof(DOVIVdrRef));
+ if (!s->vdr_ref[affected_dm_id])
+ return AVERROR(ENOMEM);
+ }
+
+ if (!s->vdr_ref[current_dm_id]) {
+ av_log(s->avctx, AV_LOG_ERROR, "Unknown previous RPU DM ID: %u\n",
+ current_dm_id);
+ goto fail;
+ }
+
+ /* Update current pointer based on current_dm_id */
+ vdr = (DOVIVdrRef *) s->vdr_ref[current_dm_id]->data;
+ s->color = &vdr->color;
+
+ /* Update values of affected_dm_id */
+ vdr = (DOVIVdrRef *) s->vdr_ref[affected_dm_id]->data;
+ color = &vdr->color;
+ color->dm_metadata_id = affected_dm_id;
+ color->scene_refresh_flag = get_ue_golomb_31(gb);
+ for (int i = 0; i < 9; i++)
+ color->ycc_to_rgb_matrix[i] = av_make_q(get_sbits(gb, 16), 1 << 13);
+ for (int i = 0; i < 3; i++) {
+ int denom = av_dovi_profile(hdr) == 4 ? (1 << 30) : (1 << 28);
+ unsigned offset = get_bits_long(gb, 32);
+ while (offset > INT_MAX) {
+ /* Ensure the result fits inside AVRational */
+ offset >>= 1;
+ denom >>= 1;
+ }
+ color->ycc_to_rgb_offset[i] = av_make_q(offset, denom);
+ }
+ for (int i = 0; i < 9; i++)
+ color->rgb_to_lms_matrix[i] = av_make_q(get_sbits(gb, 16), 1 << 14);
+
+ color->signal_eotf = get_bits(gb, 16);
+ color->signal_eotf_param0 = get_bits(gb, 16);
+ color->signal_eotf_param1 = get_bits(gb, 16);
+ color->signal_eotf_param2 = get_bits_long(gb, 32);
+ color->signal_bit_depth = get_bits(gb, 5);
+ VALIDATE(color->signal_bit_depth, 8, 16);
+ color->signal_color_space = get_bits(gb, 2);
+ color->signal_chroma_format = get_bits(gb, 2);
+ color->signal_full_range_flag = get_bits(gb, 2);
+ color->source_min_pq = get_bits(gb, 12);
+ color->source_max_pq = get_bits(gb, 12);
+ color->source_diagonal = get_bits(gb, 10);
+ }
+
+ /* FIXME: verify CRC32, requires implementation of AV_CRC_32_MPEG_2 */
+ return 0;
+
+fail:
+ ff_dovi_ctx_unref(s); /* don't leak potentially invalid state */
+ return AVERROR(EINVAL);
+}
diff --git a/libavcodec/dovi.h b/libavcodec/dovi.h
new file mode 100644
index 0000000000..f6fc7be066
--- /dev/null
+++ b/libavcodec/dovi.h
@@ -0,0 +1,62 @@
+/*
+ * Dolby Vision RPU decoder
+ *
+ * Copyright (C) 2021 Jan Ekström
+ * Copyright (C) 2021 Niklas Haas
+ *
+ * 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
+ */
+
+#ifndef AVCODEC_DOVI_H
+#define AVCODEC_DOVI_H
+
+#include "libavutil/buffer.h"
+#include "libavutil/dovi_meta.h"
+
+#include "avcodec.h"
+
+#define DOVI_MAX_DM_ID 15
+typedef struct DOVIContext {
+ AVCodecContext *avctx;
+ AVBufferRef *vdr_ref[DOVI_MAX_DM_ID+1]; ///< decoded VDR data mappings
+
+ /**
+ * Currently active RPU data header, updates on every dovi_rpu_parse().
+ */
+ AVDOVIRpuDataHeader header;
+
+ /**
+ * Currently active data mappings, or NULL. Points into memory owned by the
+ * corresponding rpu/vdr_ref, which becomes invalid on the next call to
+ * dovi_rpu_parse.
+ */
+ const AVDOVIDataMapping *mapping;
+ const AVDOVIColorMetadata *color;
+} DOVIContext;
+
+void ff_dovi_ctx_unref(DOVIContext *s);
+int ff_dovi_ctx_replace(DOVIContext *s, const DOVIContext *s0);
+
+/**
+ * Parse the contents of a Dovi RPU NAL and update the parsed values in the
+ * DOVIContext struct.
+ *
+ * Returns 0 or an error code.
+ */
+int ff_dovi_rpu_parse(DOVIContext *s, const uint8_t *rpu, size_t rpu_size);
+
+#endif /* AVCODEC_DOVI_H */
--
2.34.1
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