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/*
* 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 <stddef.h>
#include <stdint.h>
#include "libavutil/log.h"
#include "cbs.h"
#include "codec_id.h"
#include "get_bits.h"
#include "put_bits.h"
#include "refstruct.h"
enum CBSContentType {
// Unit content may contain some references to other structures, but all
// managed via buffer reference counting. The descriptor defines the
// structure offsets of every buffer reference.
CBS_CONTENT_TYPE_INTERNAL_REFS,
// Unit content is something more complex. The descriptor defines
// special functions to manage the content.
CBS_CONTENT_TYPE_COMPLEX,
};
enum {
// Maximum number of unit types described by the same non-range
// unit type descriptor.
CBS_MAX_LIST_UNIT_TYPES = 3,
// Maximum number of reference buffer offsets in any one unit.
CBS_MAX_REF_OFFSETS = 2,
// Special value used in a unit type descriptor to indicate that it
// applies to a large range of types rather than a set of discrete
// values.
CBS_UNIT_TYPE_RANGE = -1,
};
typedef const struct CodedBitstreamUnitTypeDescriptor {
// Number of entries in the unit_types array, or the special value
// CBS_UNIT_TYPE_RANGE to indicate that the range fields should be
// used instead.
int nb_unit_types;
union {
// Array of unit types that this entry describes.
CodedBitstreamUnitType list[CBS_MAX_LIST_UNIT_TYPES];
// Start and end of unit type range, used if nb_unit_types is
// CBS_UNIT_TYPE_RANGE.
struct {
CodedBitstreamUnitType start;
CodedBitstreamUnitType end;
} range;
} unit_type;
// The type of content described.
enum CBSContentType content_type;
// The size of the structure which should be allocated to contain
// the decomposed content of this type of unit.
size_t content_size;
union {
// This union's state is determined by content_type:
// ref for CBS_CONTENT_TYPE_INTERNAL_REFS,
// complex for CBS_CONTENT_TYPE_COMPLEX.
struct {
// Number of entries in the ref_offsets array.
// May be zero, then the structure is POD-like.
int nb_offsets;
// The structure must contain two adjacent elements:
// type *field;
// AVBufferRef *field_ref;
// where field points to something in the buffer referred to by
// field_ref. This offset is then set to offsetof(struct, field).
size_t offsets[CBS_MAX_REF_OFFSETS];
} ref;
struct {
void (*content_free)(FFRefStructOpaque opaque, void *content);
int (*content_clone)(void **new_content, CodedBitstreamUnit *unit);
} complex;
} type;
} CodedBitstreamUnitTypeDescriptor;
typedef struct CodedBitstreamType {
enum AVCodecID codec_id;
// A class for the private data, used to declare private AVOptions.
// This field is NULL for types that do not declare any options.
// If this field is non-NULL, the first member of the filter private data
// must be a pointer to AVClass.
const AVClass *priv_class;
size_t priv_data_size;
// List of unit type descriptors for this codec.
// Terminated by a descriptor with nb_unit_types equal to zero.
const CodedBitstreamUnitTypeDescriptor *unit_types;
// Split frag->data into coded bitstream units, creating the
// frag->units array. Fill data but not content on each unit.
// The header argument should be set if the fragment came from
// a header block, which may require different parsing for some
// codecs (e.g. the AVCC header in H.264).
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 data bitstream from unit->content into pbc.
// Return value AVERROR(ENOSPC) indicates that pbc was too small.
int (*write_unit)(CodedBitstreamContext *ctx,
CodedBitstreamUnit *unit,
PutBitContext *pbc);
// Return 1 when the unit should be dropped according to 'skip',
// 0 otherwise.
int (*discarded_unit)(CodedBitstreamContext *ctx,
const CodedBitstreamUnit *unit,
enum AVDiscard skip);
// 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);
// Reset the codec internal state.
void (*flush)(CodedBitstreamContext *ctx);
// 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);
// Helper functions for read/write of common bitstream elements, including
// generation of trace output. The simple functions are equivalent to
// their non-simple counterparts except that their range is unrestricted
// (i.e. only limited by the amount of bits used) and they lack
// the ability to use subscripts.
int ff_cbs_read_unsigned(CodedBitstreamContext *ctx, GetBitContext *gbc,
int width, const char *name,
const int *subscripts, uint32_t *write_to,
uint32_t range_min, uint32_t range_max);
int ff_cbs_read_simple_unsigned(CodedBitstreamContext *ctx, GetBitContext *gbc,
int width, const char *name, uint32_t *write_to);
int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
int width, const char *name,
const int *subscripts, uint32_t value,
uint32_t range_min, uint32_t range_max);
int ff_cbs_write_simple_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
int width, const char *name, uint32_t value);
int ff_cbs_read_signed(CodedBitstreamContext *ctx, GetBitContext *gbc,
int width, const char *name,
const int *subscripts, int32_t *write_to,
int32_t range_min, int32_t range_max);
int ff_cbs_write_signed(CodedBitstreamContext *ctx, PutBitContext *pbc,
int width, const char *name,
const int *subscripts, int32_t value,
int32_t range_min, int32_t range_max);
// The largest unsigned value representable in N bits, suitable for use as
// range_max in the above functions.
#define MAX_UINT_BITS(length) ((UINT64_C(1) << (length)) - 1)
// The largest signed value representable in N bits, suitable for use as
// range_max in the above functions.
#define MAX_INT_BITS(length) ((INT64_C(1) << ((length) - 1)) - 1)
// The smallest signed value representable in N bits, suitable for use as
// range_min in the above functions.
#define MIN_INT_BITS(length) (-(INT64_C(1) << ((length) - 1)))
// Start of a syntax element during read tracing.
#define CBS_TRACE_READ_START() \
GetBitContext trace_start; \
do { \
if (ctx->trace_enable) \
trace_start = *gbc; \
} while (0)
// End of a syntax element for tracing, make callback.
#define CBS_TRACE_READ_END() \
do { \
if (ctx->trace_enable) { \
int start_position = get_bits_count(&trace_start); \
int end_position = get_bits_count(gbc); \
av_assert0(start_position <= end_position); \
ctx->trace_read_callback(ctx->trace_context, &trace_start, \
end_position - start_position, \
name, subscripts, value); \
} \
} while (0)
// End of a syntax element with no subscript entries.
#define CBS_TRACE_READ_END_NO_SUBSCRIPTS() \
do { \
const int *subscripts = NULL; \
CBS_TRACE_READ_END(); \
} while (0)
// End of a syntax element which is made up of subelements which
// are aleady traced, so we are only showing the value.
#define CBS_TRACE_READ_END_VALUE_ONLY() \
do { \
if (ctx->trace_enable) { \
ctx->trace_read_callback(ctx->trace_context, &trace_start, 0, \
name, subscripts, value); \
} \
} while (0)
// Start of a syntax element during write tracing.
#define CBS_TRACE_WRITE_START() \
int start_position; \
do { \
if (ctx->trace_enable) \
start_position = put_bits_count(pbc);; \
} while (0)
// End of a syntax element for tracing, make callback.
#define CBS_TRACE_WRITE_END() \
do { \
if (ctx->trace_enable) { \
int end_position = put_bits_count(pbc); \
av_assert0(start_position <= end_position); \
ctx->trace_write_callback(ctx->trace_context, pbc, \
end_position - start_position, \
name, subscripts, value); \
} \
} while (0)
// End of a syntax element with no subscript entries.
#define CBS_TRACE_WRITE_END_NO_SUBSCRIPTS() \
do { \
const int *subscripts = NULL; \
CBS_TRACE_WRITE_END(); \
} while (0)
// End of a syntax element which is made up of subelements which are
// aleady traced, so we are only showing the value. This forges a
// PutBitContext to point to the position of the start of the syntax
// element, but the other state doesn't matter because length is zero.
#define CBS_TRACE_WRITE_END_VALUE_ONLY() \
do { \
if (ctx->trace_enable) { \
PutBitContext tmp; \
init_put_bits(&tmp, pbc->buf, start_position); \
skip_put_bits(&tmp, start_position); \
ctx->trace_write_callback(ctx->trace_context, &tmp, 0, \
name, subscripts, value); \
} \
} while (0)
#define TYPE_LIST(...) { __VA_ARGS__ }
#define CBS_UNIT_TYPE_POD(type_, structure) { \
.nb_unit_types = 1, \
.unit_type.list = { type_ }, \
.content_type = CBS_CONTENT_TYPE_INTERNAL_REFS, \
.content_size = sizeof(structure), \
.type.ref = { .nb_offsets = 0 }, \
}
#define CBS_UNIT_RANGE_POD(range_start, range_end, structure) { \
.nb_unit_types = CBS_UNIT_TYPE_RANGE, \
.unit_type.range.start = range_start, \
.unit_type.range.end = range_end, \
.content_type = CBS_CONTENT_TYPE_INTERNAL_REFS, \
.content_size = sizeof(structure), \
.type.ref = { .nb_offsets = 0 }, \
}
#define CBS_UNIT_TYPES_INTERNAL_REF(types, structure, ref_field) { \
.nb_unit_types = FF_ARRAY_ELEMS((CodedBitstreamUnitType[])TYPE_LIST types), \
.unit_type.list = TYPE_LIST types, \
.content_type = CBS_CONTENT_TYPE_INTERNAL_REFS, \
.content_size = sizeof(structure), \
.type.ref = { .nb_offsets = 1, \
.offsets = { offsetof(structure, ref_field) } }, \
}
#define CBS_UNIT_TYPE_INTERNAL_REF(type, structure, ref_field) \
CBS_UNIT_TYPES_INTERNAL_REF((type), structure, ref_field)
#define CBS_UNIT_RANGE_INTERNAL_REF(range_start, range_end, structure, ref_field) { \
.nb_unit_types = CBS_UNIT_TYPE_RANGE, \
.unit_type.range.start = range_start, \
.unit_type.range.end = range_end, \
.content_type = CBS_CONTENT_TYPE_INTERNAL_REFS, \
.content_size = sizeof(structure), \
.type.ref = { .nb_offsets = 1, \
.offsets = { offsetof(structure, ref_field) } }, \
}
#define CBS_UNIT_TYPES_COMPLEX(types, structure, free_func) { \
.nb_unit_types = FF_ARRAY_ELEMS((CodedBitstreamUnitType[])TYPE_LIST types), \
.unit_type.list = TYPE_LIST types, \
.content_type = CBS_CONTENT_TYPE_COMPLEX, \
.content_size = sizeof(structure), \
.type.complex = { .content_free = free_func }, \
}
#define CBS_UNIT_TYPE_COMPLEX(type, structure, free_func) \
CBS_UNIT_TYPES_COMPLEX((type), structure, free_func)
#define CBS_UNIT_TYPE_END_OF_LIST { .nb_unit_types = 0 }
extern const CodedBitstreamType ff_cbs_type_av1;
extern const CodedBitstreamType ff_cbs_type_h264;
extern const CodedBitstreamType ff_cbs_type_h265;
extern const CodedBitstreamType ff_cbs_type_h266;
extern const CodedBitstreamType ff_cbs_type_jpeg;
extern const CodedBitstreamType ff_cbs_type_mpeg2;
extern const CodedBitstreamType ff_cbs_type_vp8;
extern const CodedBitstreamType ff_cbs_type_vp9;
#endif /* AVCODEC_CBS_INTERNAL_H */