[FFmpeg-devel] [PATCH 05/18] lavc: Add coded bitstream read/write API
Mark Thompson
sw at jkqxz.net
Mon Aug 21 01:41:33 EEST 2017
(cherry picked from commit 18f1706f331bf5dd565774eae680508c8d3a97ad)
---
configure | 1 +
libavcodec/Makefile | 1 +
libavcodec/cbs.c | 460 ++++++++++++++++++++++++++++++++++++++++++++++
libavcodec/cbs.h | 274 +++++++++++++++++++++++++++
libavcodec/cbs_internal.h | 83 +++++++++
5 files changed, 819 insertions(+)
create mode 100644 libavcodec/cbs.c
create mode 100644 libavcodec/cbs.h
create mode 100644 libavcodec/cbs_internal.h
diff --git a/configure b/configure
index 7201941c36..c7c995ceb5 100755
--- a/configure
+++ b/configure
@@ -2088,6 +2088,7 @@ CONFIG_EXTRA="
blockdsp
bswapdsp
cabac
+ cbs
dirac_parse
dvprofile
exif
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index b0c39ac040..46c0ec9011 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -59,6 +59,7 @@ OBJS-$(CONFIG_AUDIODSP) += audiodsp.o
OBJS-$(CONFIG_BLOCKDSP) += blockdsp.o
OBJS-$(CONFIG_BSWAPDSP) += bswapdsp.o
OBJS-$(CONFIG_CABAC) += cabac.o
+OBJS-$(CONFIG_CBS) += cbs.o
OBJS-$(CONFIG_CRYSTALHD) += crystalhd.o
OBJS-$(CONFIG_DCT) += dct.o dct32_fixed.o dct32_float.o
OBJS-$(CONFIG_ERROR_RESILIENCE) += error_resilience.o
diff --git a/libavcodec/cbs.c b/libavcodec/cbs.c
new file mode 100644
index 0000000000..1d73c30dd6
--- /dev/null
+++ b/libavcodec/cbs.c
@@ -0,0 +1,460 @@
+/*
+ * 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 <string.h>
+
+#include "config.h"
+
+#include "libavutil/avassert.h"
+#include "libavutil/common.h"
+
+#include "cbs.h"
+#include "cbs_internal.h"
+
+
+static const CodedBitstreamType *cbs_type_table[] = {
+};
+
+int ff_cbs_init(CodedBitstreamContext *ctx,
+ enum AVCodecID codec_id, void *log_ctx)
+{
+ const CodedBitstreamType *type;
+ int i;
+
+ type = NULL;
+ for (i = 0; i < FF_ARRAY_ELEMS(cbs_type_table); i++) {
+ if (cbs_type_table[i]->codec_id == codec_id) {
+ type = cbs_type_table[i];
+ break;
+ }
+ }
+ if (!type)
+ return AVERROR(EINVAL);
+
+ ctx->log_ctx = log_ctx;
+ ctx->codec = type;
+
+ ctx->priv_data = av_mallocz(ctx->codec->priv_data_size);
+ if (!ctx->priv_data)
+ return AVERROR(ENOMEM);
+
+ ctx->decompose_unit_types = NULL;
+
+ ctx->trace_enable = 0;
+ ctx->trace_level = AV_LOG_TRACE;
+
+ return 0;
+}
+
+void ff_cbs_close(CodedBitstreamContext *ctx)
+{
+ if (ctx->codec && ctx->codec->close)
+ ctx->codec->close(ctx);
+
+ av_freep(&ctx->priv_data);
+}
+
+static void cbs_unit_uninit(CodedBitstreamContext *ctx,
+ CodedBitstreamUnit *unit)
+{
+ if (ctx->codec->free_unit && unit->content && !unit->content_external)
+ ctx->codec->free_unit(unit);
+
+ av_freep(&unit->data);
+ unit->data_size = 0;
+ unit->data_bit_padding = 0;
+}
+
+void ff_cbs_fragment_uninit(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag)
+{
+ int i;
+
+ for (i = 0; i < frag->nb_units; i++)
+ cbs_unit_uninit(ctx, &frag->units[i]);
+ av_freep(&frag->units);
+ frag->nb_units = 0;
+
+ av_freep(&frag->data);
+ frag->data_size = 0;
+ frag->data_bit_padding = 0;
+}
+
+static int cbs_read_fragment_content(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag)
+{
+ int err, i, j;
+
+ for (i = 0; i < frag->nb_units; i++) {
+ if (ctx->decompose_unit_types) {
+ for (j = 0; j < ctx->nb_decompose_unit_types; j++) {
+ if (ctx->decompose_unit_types[j] == frag->units[i].type)
+ break;
+ }
+ if (j >= ctx->nb_decompose_unit_types)
+ continue;
+ }
+
+ err = ctx->codec->read_unit(ctx, &frag->units[i]);
+ if (err == AVERROR(ENOSYS)) {
+ av_log(ctx->log_ctx, AV_LOG_WARNING,
+ "Decomposition unimplemented for unit %d "
+ "(type %d).\n", i, frag->units[i].type);
+ } else if (err < 0) {
+ av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to read unit %d "
+ "(type %d).\n", i, frag->units[i].type);
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+int ff_cbs_read_extradata(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ const AVCodecParameters *par)
+{
+ int err;
+
+ memset(frag, 0, sizeof(*frag));
+
+ frag->data = par->extradata;
+ frag->data_size = par->extradata_size;
+
+ err = ctx->codec->split_fragment(ctx, frag, 1);
+ if (err < 0)
+ return err;
+
+ frag->data = NULL;
+ frag->data_size = 0;
+
+ return cbs_read_fragment_content(ctx, frag);
+}
+
+int ff_cbs_read_packet(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ const AVPacket *pkt)
+{
+ int err;
+
+ memset(frag, 0, sizeof(*frag));
+
+ frag->data = pkt->data;
+ frag->data_size = pkt->size;
+
+ err = ctx->codec->split_fragment(ctx, frag, 0);
+ if (err < 0)
+ return err;
+
+ frag->data = NULL;
+ frag->data_size = 0;
+
+ return cbs_read_fragment_content(ctx, frag);
+}
+
+int ff_cbs_read(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ const uint8_t *data, size_t size)
+{
+ int err;
+
+ memset(frag, 0, sizeof(*frag));
+
+ // (We won't write to this during split.)
+ frag->data = (uint8_t*)data;
+ frag->data_size = size;
+
+ err = ctx->codec->split_fragment(ctx, frag, 0);
+ if (err < 0)
+ return err;
+
+ frag->data = NULL;
+ frag->data_size = 0;
+
+ return cbs_read_fragment_content(ctx, frag);
+}
+
+
+int ff_cbs_write_fragment_data(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag)
+{
+ int err, i;
+
+ for (i = 0; i < frag->nb_units; i++) {
+ if (!frag->units[i].content)
+ continue;
+
+ err = ctx->codec->write_unit(ctx, &frag->units[i]);
+ if (err < 0) {
+ av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to write unit %d "
+ "(type %d).\n", i, frag->units[i].type);
+ return err;
+ }
+ }
+
+ err = ctx->codec->assemble_fragment(ctx, frag);
+ if (err < 0) {
+ av_log(ctx->log_ctx, AV_LOG_ERROR, "Failed to assemble fragment.\n");
+ return err;
+ }
+
+ return 0;
+}
+
+int ff_cbs_write_extradata(CodedBitstreamContext *ctx,
+ AVCodecParameters *par,
+ CodedBitstreamFragment *frag)
+{
+ int err;
+
+ err = ff_cbs_write_fragment_data(ctx, frag);
+ if (err < 0)
+ return err;
+
+ av_freep(&par->extradata);
+
+ par->extradata = av_malloc(frag->data_size +
+ AV_INPUT_BUFFER_PADDING_SIZE);
+ if (!par->extradata)
+ return AVERROR(ENOMEM);
+
+ memcpy(par->extradata, frag->data, frag->data_size);
+ memset(par->extradata + frag->data_size, 0,
+ AV_INPUT_BUFFER_PADDING_SIZE);
+ par->extradata_size = frag->data_size;
+
+ return 0;
+}
+
+int ff_cbs_write_packet(CodedBitstreamContext *ctx,
+ AVPacket *pkt,
+ CodedBitstreamFragment *frag)
+{
+ int err;
+
+ err = ff_cbs_write_fragment_data(ctx, frag);
+ if (err < 0)
+ return err;
+
+ av_new_packet(pkt, frag->data_size);
+ if (err < 0)
+ return err;
+
+ memcpy(pkt->data, frag->data, frag->data_size);
+ pkt->size = frag->data_size;
+
+ return 0;
+}
+
+
+void ff_cbs_trace_header(CodedBitstreamContext *ctx,
+ const char *name)
+{
+ if (!ctx->trace_enable)
+ return;
+
+ av_log(ctx->log_ctx, ctx->trace_level, "%s\n", name);
+}
+
+void ff_cbs_trace_syntax_element(CodedBitstreamContext *ctx, int position,
+ const char *name, const char *bits,
+ int64_t value)
+{
+ size_t name_len, bits_len;
+ int pad;
+
+ if (!ctx->trace_enable)
+ return;
+
+ av_assert0(value >= INT_MIN && value <= UINT32_MAX);
+
+ name_len = strlen(name);
+ bits_len = strlen(bits);
+
+ if (name_len + bits_len > 60)
+ pad = bits_len + 2;
+ else
+ pad = 61 - name_len;
+
+ av_log(ctx->log_ctx, ctx->trace_level, "%-10d %s%*s = %"PRId64"\n",
+ position, name, pad, bits, value);
+}
+
+int ff_cbs_read_unsigned(CodedBitstreamContext *ctx, GetBitContext *gbc,
+ int width, const char *name, uint32_t *write_to,
+ uint32_t range_min, uint32_t range_max)
+{
+ uint32_t value;
+ int position;
+
+ av_assert0(width <= 32);
+
+ if (ctx->trace_enable)
+ position = get_bits_count(gbc);
+
+ value = get_bits_long(gbc, width);
+
+ if (ctx->trace_enable) {
+ char bits[33];
+ int i;
+ for (i = 0; i < width; i++)
+ bits[i] = value >> (width - i - 1) & 1 ? '1' : '0';
+ bits[i] = 0;
+
+ ff_cbs_trace_syntax_element(ctx, position, name, bits, value);
+ }
+
+ if (value < range_min || value > range_max) {
+ av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
+ "%"PRIu32", but must be in [%"PRIu32",%"PRIu32"].\n",
+ name, value, range_min, range_max);
+ return AVERROR_INVALIDDATA;
+ }
+
+ *write_to = value;
+ return 0;
+}
+
+int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
+ int width, const char *name, uint32_t value,
+ uint32_t range_min, uint32_t range_max)
+{
+ av_assert0(width <= 32);
+
+ if (value < range_min || value > range_max) {
+ av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
+ "%"PRIu32", but must be in [%"PRIu32",%"PRIu32"].\n",
+ name, value, range_min, range_max);
+ return AVERROR_INVALIDDATA;
+ }
+
+ if (put_bits_left(pbc) < width)
+ return AVERROR(ENOSPC);
+
+ if (ctx->trace_enable) {
+ char bits[33];
+ int i;
+ for (i = 0; i < width; i++)
+ bits[i] = value >> (width - i - 1) & 1 ? '1' : '0';
+ bits[i] = 0;
+
+ ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc), name, bits, value);
+ }
+
+ if (width < 32)
+ put_bits(pbc, width, value);
+ else
+ put_bits32(pbc, value);
+
+ return 0;
+}
+
+
+static int cbs_insert_unit(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ int position)
+{
+ CodedBitstreamUnit *units;
+
+ units = av_malloc_array(frag->nb_units + 1, sizeof(*units));
+ if (!units)
+ return AVERROR(ENOMEM);
+
+ if (position > 0)
+ memcpy(units, frag->units, position * sizeof(*units));
+ if (position < frag->nb_units)
+ memcpy(units + position + 1, frag->units + position,
+ (frag->nb_units - position) * sizeof(*units));
+
+ memset(units + position, 0, sizeof(*units));
+
+ av_freep(&frag->units);
+ frag->units = units;
+ ++frag->nb_units;
+
+ return 0;
+}
+
+int ff_cbs_insert_unit_content(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ int position, uint32_t type,
+ void *content)
+{
+ int err;
+
+ if (position == -1)
+ position = frag->nb_units;
+ av_assert0(position >= 0 && position <= frag->nb_units);
+
+ err = cbs_insert_unit(ctx, frag, position);
+ if (err < 0)
+ return err;
+
+ frag->units[position].type = type;
+ frag->units[position].content = content;
+ frag->units[position].content_external = 1;
+
+ return 0;
+}
+
+int ff_cbs_insert_unit_data(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ int position, uint32_t type,
+ uint8_t *data, size_t data_size)
+{
+ int err;
+
+ if (position == -1)
+ position = frag->nb_units;
+ av_assert0(position >= 0 && position <= frag->nb_units);
+
+ err = cbs_insert_unit(ctx, frag, position);
+ if (err < 0)
+ return err;
+
+ frag->units[position].type = type;
+ frag->units[position].data = data;
+ frag->units[position].data_size = data_size;
+
+ return 0;
+}
+
+int ff_cbs_delete_unit(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ int position)
+{
+ if (position < 0 || position >= frag->nb_units)
+ return AVERROR(EINVAL);
+
+ cbs_unit_uninit(ctx, &frag->units[position]);
+
+ --frag->nb_units;
+
+ if (frag->nb_units == 0) {
+ av_freep(&frag->units);
+
+ } else {
+ memmove(frag->units + position,
+ frag->units + position + 1,
+ (frag->nb_units - position) * sizeof(*frag->units));
+
+ // Don't bother reallocating the unit array.
+ }
+
+ return 0;
+}
diff --git a/libavcodec/cbs.h b/libavcodec/cbs.h
new file mode 100644
index 0000000000..eeaff379e5
--- /dev/null
+++ b/libavcodec/cbs.h
@@ -0,0 +1,274 @@
+/*
+ * 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_CBS_H
+#define AVCODEC_CBS_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "avcodec.h"
+
+
+struct CodedBitstreamType;
+
+/**
+ * Coded bitstream unit structure.
+ *
+ * A bitstream unit the the smallest element of a bitstream which
+ * is meaningful on its own. For example, an H.264 NAL unit.
+ *
+ * See the codec-specific header for the meaning of this for any
+ * particular codec.
+ */
+typedef struct CodedBitstreamUnit {
+ /**
+ * Codec-specific type of this unit.
+ */
+ uint32_t type;
+
+ /**
+ * Pointer to the bitstream form of this unit.
+ *
+ * May be NULL if the unit currently only exists in decomposed form.
+ */
+ uint8_t *data;
+ /**
+ * The number of bytes in the bitstream (including any padding bits
+ * in the final byte).
+ */
+ size_t data_size;
+ /**
+ * The number of bits which should be ignored in the final byte.
+ *
+ * This supports non-byte-aligned bitstreams.
+ */
+ size_t data_bit_padding;
+
+ /**
+ * Pointer to the decomposed form of this unit.
+ *
+ * The type of this structure depends on both the codec and the
+ * type of this unit. May be NULL if the unit only exists in
+ * bitstream form.
+ */
+ void *content;
+ /**
+ * Whether the content was supplied externally.
+ *
+ * If so, it should not be freed when freeing the unit.
+ */
+ int content_external;
+} CodedBitstreamUnit;
+
+/**
+ * Coded bitstream fragment structure, combining one or more units.
+ *
+ * This is any sequence of units. It need not form some greater whole,
+ * though in many cases it will. For example, an H.264 access unit,
+ * which is composed of a sequence of H.264 NAL units.
+ */
+typedef struct CodedBitstreamFragment {
+ /**
+ * Pointer to the bitstream form of this fragment.
+ *
+ * May be NULL if the fragment only exists as component units.
+ */
+ uint8_t *data;
+ /**
+ * The number of bytes in the bitstream.
+ *
+ * The number of bytes in the bitstream (including any padding bits
+ * in the final byte).
+ */
+ size_t data_size;
+ /**
+ * The number of bits which should be ignored in the final byte.
+ */
+ size_t data_bit_padding;
+
+ /**
+ * Number of units in this fragment.
+ *
+ * This may be zero if the fragment only exists in bistream form
+ * and has not been decomposed.
+ */
+ int nb_units;
+ /**
+ * Pointer to an array of units of length nb_units.
+ *
+ * Must be NULL if nb_units is zero.
+ */
+ CodedBitstreamUnit *units;
+} CodedBitstreamFragment;
+
+/**
+ * Context structure for coded bitstream operations.
+ */
+typedef struct CodedBitstreamContext {
+ /**
+ * Logging context to be passed to all av_log() calls associated
+ * with this context.
+ */
+ void *log_ctx;
+
+ /**
+ * Internal codec-specific hooks.
+ */
+ const struct CodedBitstreamType *codec;
+
+ /**
+ * Internal codec-specific data.
+ *
+ * This contains any information needed when reading/writing
+ * bitsteams which will not necessarily be present in a fragment.
+ * For example, for H.264 it contains all currently visible
+ * parameter sets - they are required to determine the bitstream
+ * syntax but need not be present in every access unit.
+ */
+ void *priv_data;
+
+ /**
+ * Array of unit types which should be decomposed when reading.
+ *
+ * Types not in this list will be available in bitstream form only.
+ * If NULL, all supported types will be decomposed.
+ */
+ uint32_t *decompose_unit_types;
+ /**
+ * Length of the decompose_unit_types array.
+ */
+ int nb_decompose_unit_types;
+
+ /**
+ * Enable trace output during read/write operations.
+ */
+ int trace_enable;
+ /**
+ * Log level to use for trace output.
+ *
+ * From AV_LOG_*; defaults to AV_LOG_TRACE.
+ */
+ int trace_level;
+} CodedBitstreamContext;
+
+
+/**
+ * Initialise a new context for the given codec.
+ */
+int ff_cbs_init(CodedBitstreamContext *ctx,
+ enum AVCodecID codec_id, void *log_ctx);
+
+/**
+ * Close a context and free all internal state.
+ */
+void ff_cbs_close(CodedBitstreamContext *ctx);
+
+
+/**
+ * Read the extradata bitstream found in codec parameters into a
+ * fragment, then split into units and decompose.
+ *
+ * This also updates the internal state, so will need to be called for
+ * codecs with extradata to read parameter sets necessary for further
+ * parsing even if the fragment itself is not desired.
+ */
+int ff_cbs_read_extradata(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ const AVCodecParameters *par);
+
+/**
+ * Read the data bitstream from a packet into a fragment, then
+ * split into units and decompose.
+ */
+int ff_cbs_read_packet(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ const AVPacket *pkt);
+
+/**
+ * Read a bitstream from a memory region into a fragment, then
+ * split into units and decompose.
+ */
+int ff_cbs_read(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ const uint8_t *data, size_t size);
+
+
+/**
+ * Write the content of the fragment to its own internal buffer.
+ *
+ * Writes the content of all units and then assembles them into a new
+ * data buffer. When modifying the content of decomposed units, this
+ * can be used to regenerate the bitstream form of units or the whole
+ * fragment so that it can be extracted for other use.
+ */
+int ff_cbs_write_fragment_data(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag);
+
+/**
+ * Write the bitstream of a fragment to the extradata in codec parameters.
+ */
+int ff_cbs_write_extradata(CodedBitstreamContext *ctx,
+ AVCodecParameters *par,
+ CodedBitstreamFragment *frag);
+
+/**
+ * Write the bitstream of a fragment to a packet.
+ */
+int ff_cbs_write_packet(CodedBitstreamContext *ctx,
+ AVPacket *pkt,
+ CodedBitstreamFragment *frag);
+
+
+/**
+ * Free all allocated memory in a fragment.
+ */
+void ff_cbs_fragment_uninit(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag);
+
+
+/**
+ * Insert a new unit into a fragment with the given content.
+ *
+ * The content structure continues to be owned by the caller, and
+ * will not be freed when the unit is.
+ */
+int ff_cbs_insert_unit_content(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ int position, uint32_t type,
+ void *content);
+
+/**
+ * Insert a new unit into a fragment with the given data bitstream.
+ *
+ * The data buffer will be owned by the unit after this operation.
+ */
+int ff_cbs_insert_unit_data(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ int position, uint32_t type,
+ uint8_t *data, size_t data_size);
+
+/**
+ * Delete a unit from a fragment and free all memory it uses.
+ */
+int ff_cbs_delete_unit(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ int position);
+
+
+#endif /* AVCODEC_CBS_H */
diff --git a/libavcodec/cbs_internal.h b/libavcodec/cbs_internal.h
new file mode 100644
index 0000000000..3bbc3355c2
--- /dev/null
+++ b/libavcodec/cbs_internal.h
@@ -0,0 +1,83 @@
+/*
+ * 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_CBS_INTERNAL_H
+#define AVCODEC_CBS_INTERNAL_H
+
+#include "avcodec.h"
+#include "cbs.h"
+#include "get_bits.h"
+#include "put_bits.h"
+
+
+typedef struct CodedBitstreamType {
+ enum AVCodecID codec_id;
+
+ size_t priv_data_size;
+
+ // Split frag->data into coded bitstream units, creating the
+ // frag->units array. Fill data but not content on each unit.
+ int (*split_fragment)(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag,
+ int header);
+
+ // Read the unit->data bitstream and decompose it, creating
+ // unit->content.
+ int (*read_unit)(CodedBitstreamContext *ctx,
+ CodedBitstreamUnit *unit);
+
+ // Write the unit->data bitstream from unit->content.
+ int (*write_unit)(CodedBitstreamContext *ctx,
+ CodedBitstreamUnit *unit);
+
+ // Read the data from all of frag->units and assemble it into
+ // a bitstream for the whole fragment.
+ int (*assemble_fragment)(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *frag);
+
+ // Free the content and data of a single unit.
+ void (*free_unit)(CodedBitstreamUnit *unit);
+
+ // Free the codec internal state.
+ void (*close)(CodedBitstreamContext *ctx);
+} CodedBitstreamType;
+
+
+// Helper functions for trace output.
+
+void ff_cbs_trace_header(CodedBitstreamContext *ctx,
+ const char *name);
+
+void ff_cbs_trace_syntax_element(CodedBitstreamContext *ctx,
+ int position, const char *name,
+ const char *bitstring, int64_t value);
+
+
+// Helper functions for read/write of common bitstream elements, including
+// generation of trace output.
+
+int ff_cbs_read_unsigned(CodedBitstreamContext *ctx, GetBitContext *gbc,
+ int width, const char *name, uint32_t *write_to,
+ uint32_t range_min, uint32_t range_max);
+
+int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
+ int width, const char *name, uint32_t value,
+ uint32_t range_min, uint32_t range_max);
+
+
+#endif /* AVCODEC_CBS_INTERNAL_H */
--
2.11.0
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