| /* |
| * 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 "avcodec.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 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. |
| */ |
| 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 AVCodecContext *avctx); |
| |
| /** |
| * 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 of the given size in the unit. |
| * |
| * The content will be zeroed. |
| */ |
| int ff_cbs_alloc_unit_content(CodedBitstreamUnit *unit, |
| size_t size, |
| void (*free)(void *opaque, uint8_t *content)); |
| |
| /** |
| * Allocate a new internal content buffer matching the type of the unit. |
| * |
| * The content will be zeroed. |
| */ |
| int ff_cbs_alloc_unit_content2(CodedBitstreamContext *ctx, |
| CodedBitstreamUnit *unit); |
| |
| |
| /** |
| * Allocate a new internal data buffer of the given size in the unit. |
| * |
| * The data buffer will have input padding. |
| */ |
| int ff_cbs_alloc_unit_data(CodedBitstreamUnit *unit, |
| size_t size); |
| |
| /** |
| * 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); |
| |
| /** |
| * Insert a new unit into 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_insert_unit_data(CodedBitstreamFragment *frag, |
| int position, |
| 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 */ |