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| -rw-r--r-- | media/ffvpx/libavcodec/cbs.h | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/media/ffvpx/libavcodec/cbs.h b/media/ffvpx/libavcodec/cbs.h new file mode 100644 index 0000000000..ee21623dac --- /dev/null +++ b/media/ffvpx/libavcodec/cbs.h @@ -0,0 +1,436 @@ +/* + * 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 "libavutil/buffer.h" + +#include "codec_id.h" +#include "codec_par.h" +#include "packet.h" + + +/* + * This defines a framework for converting between a coded bitstream + * and structures defining all individual syntax elements found in + * such a stream. + * + * Conversion in both directions is possible. Given a coded bitstream + * (any meaningful fragment), it can be parsed and decomposed into + * syntax elements stored in a set of codec-specific structures. + * Similarly, given a set of those same codec-specific structures the + * syntax elements can be serialised and combined to create a coded + * bitstream. + */ + +struct AVCodecContext; +struct CodedBitstreamType; + +/** + * The codec-specific type of a bitstream unit. + * + * AV1: obu_type + * H.264 / AVC: nal_unit_type + * H.265 / HEVC: nal_unit_type + * JPEG: marker value (without 0xff prefix) + * MPEG-2: start code value (without prefix) + * VP9: unused, set to zero (every unit is a frame) + */ +typedef uint32_t CodedBitstreamUnitType; + +/** + * Coded bitstream unit structure. + * + * A bitstream unit 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. + */ + CodedBitstreamUnitType type; + + /** + * Pointer to the directly-parsable 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; + /** + * A reference to the buffer containing data. + * + * Must be set if data is not NULL. + */ + AVBufferRef *data_ref; + + /** + * 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; + /** + * If content is reference counted, a reference to the buffer containing + * content. Null if content is not reference counted. + */ + AVBufferRef *content_ref; +} 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; + /** + * A reference to the buffer containing data. + * + * Must be set if data is not NULL. + */ + AVBufferRef *data_ref; + + /** + * Number of units in this fragment. + * + * This may be zero if the fragment only exists in bitstream form + * and has not been decomposed. + */ + int nb_units; + + /** + * Number of allocated units. + * + * Must always be >= nb_units; designed for internal use by cbs. + */ + int nb_units_allocated; + + /** + * Pointer to an array of units of length nb_units_allocated. + * Only the first nb_units are valid. + * + * Must be NULL if nb_units_allocated 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. + */ + const CodedBitstreamUnitType *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; + + /** + * Write buffer. Used as intermediate buffer when writing units. + * For internal use of cbs only. + */ + uint8_t *write_buffer; + size_t write_buffer_size; +} CodedBitstreamContext; + + +/** + * Table of all supported codec IDs. + * + * Terminated by AV_CODEC_ID_NONE. + */ +extern const enum AVCodecID ff_cbs_all_codec_ids[]; + + +/** + * Create and initialise a new context for the given codec. + */ +int ff_cbs_init(CodedBitstreamContext **ctx, + enum AVCodecID codec_id, void *log_ctx); + +/** + * Reset all internal state in a context. + */ +void ff_cbs_flush(CodedBitstreamContext *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. + * + * The fragment must have been zeroed or reset via ff_cbs_fragment_reset + * before use. + */ +int ff_cbs_read_extradata(CodedBitstreamContext *ctx, + CodedBitstreamFragment *frag, + const AVCodecParameters *par); + +/** + * Read the extradata bitstream found in a codec context into a + * fragment, then split into units and decompose. + * + * This acts identical to ff_cbs_read_extradata() for the case where + * you already have a codec context. + */ +int ff_cbs_read_extradata_from_codec(CodedBitstreamContext *ctx, + CodedBitstreamFragment *frag, + const struct AVCodecContext *avctx); + +int ff_cbs_read_packet_side_data(CodedBitstreamContext *ctx, + CodedBitstreamFragment *frag, + const AVPacket *pkt); + +/** + * Read the data bitstream from a packet into a fragment, then + * split into units and decompose. + * + * This also updates the internal state of the coded bitstream context + * with any persistent data from the fragment which may be required to + * read following fragments (e.g. parameter sets). + * + * The fragment must have been zeroed or reset via ff_cbs_fragment_reset + * before use. + */ +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. + * + * This also updates the internal state of the coded bitstream context + * with any persistent data from the fragment which may be required to + * read following fragments (e.g. parameter sets). + * + * The fragment must have been zeroed or reset via ff_cbs_fragment_reset + * before use. + */ +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. + * + * This also updates the internal state of the coded bitstream context + * with any persistent data from the fragment which may be required to + * write following fragments (e.g. parameter sets). + */ +int ff_cbs_write_fragment_data(CodedBitstreamContext *ctx, + CodedBitstreamFragment *frag); + +/** + * Write the bitstream of a fragment to the extradata in codec parameters. + * + * Modifies context and fragment as ff_cbs_write_fragment_data does and + * replaces any existing extradata in the structure. + */ +int ff_cbs_write_extradata(CodedBitstreamContext *ctx, + AVCodecParameters *par, + CodedBitstreamFragment *frag); + +/** + * Write the bitstream of a fragment to a packet. + * + * Modifies context and fragment as ff_cbs_write_fragment_data does. + * + * On success, the packet's buf is unreferenced and its buf, data and + * size fields are set to the corresponding values from the newly updated + * fragment; other fields are not touched. On failure, the packet is not + * touched at all. + */ +int ff_cbs_write_packet(CodedBitstreamContext *ctx, + AVPacket *pkt, + CodedBitstreamFragment *frag); + + +/** + * Free the units contained in a fragment as well as the fragment's + * own data buffer, but not the units array itself. + */ +void ff_cbs_fragment_reset(CodedBitstreamFragment *frag); + +/** + * Free the units array of a fragment in addition to what + * ff_cbs_fragment_reset does. + */ +void ff_cbs_fragment_free(CodedBitstreamFragment *frag); + +/** + * Allocate a new internal content buffer matching the type of the unit. + * + * The content will be zeroed. + */ +int ff_cbs_alloc_unit_content(CodedBitstreamContext *ctx, + CodedBitstreamUnit *unit); + +/** + * Insert a new unit into a fragment with the given content. + * + * The content structure continues to be owned by the caller if + * content_buf is not supplied. + */ +int ff_cbs_insert_unit_content(CodedBitstreamFragment *frag, + int position, + CodedBitstreamUnitType type, + void *content, + AVBufferRef *content_buf); + +/** + * Add a new unit to a fragment with the given data bitstream. + * + * If data_buf is not supplied then data must have been allocated with + * av_malloc() and will on success become owned by the unit after this + * call or freed on error. + */ +int ff_cbs_append_unit_data(CodedBitstreamFragment *frag, + CodedBitstreamUnitType type, + uint8_t *data, size_t data_size, + AVBufferRef *data_buf); + +/** + * Delete a unit from a fragment and free all memory it uses. + * + * Requires position to be >= 0 and < frag->nb_units. + */ +void ff_cbs_delete_unit(CodedBitstreamFragment *frag, + int position); + + +/** + * Make the content of a unit refcounted. + * + * If the unit is not refcounted, this will do a deep copy of the unit + * content to new refcounted buffers. + * + * It is not valid to call this function on a unit which does not have + * decomposed content. + */ +int ff_cbs_make_unit_refcounted(CodedBitstreamContext *ctx, + CodedBitstreamUnit *unit); + +/** + * Make the content of a unit writable so that internal fields can be + * modified. + * + * If it is known that there are no other references to the content of + * the unit, does nothing and returns success. Otherwise (including the + * case where the unit content is not refcounted), it does a full clone + * of the content (including any internal buffers) to make a new copy, + * and replaces the existing references inside the unit with that. + * + * It is not valid to call this function on a unit which does not have + * decomposed content. + */ +int ff_cbs_make_unit_writable(CodedBitstreamContext *ctx, + CodedBitstreamUnit *unit); + + +#endif /* AVCODEC_CBS_H */ |