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7c92eaace2
All cbs-functions to write units share a common pattern: 1. They check whether they have a write buffer (that is used to store the unit's data until the needed size becomes known after writing the unit when a dedicated buffer will be allocated). 2. They use this buffer for a PutBitContext. 3. The (codec-specific) writing takes place through the PutBitContext. 4. The return value is checked. AVERROR(ENOSPC) here always indicates that the buffer was too small and leads to a reallocation of said buffer. 5. The final buffer will be allocated and the data copied. This commit factors this common code out in a single function in cbs.c. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
118 lines
4.5 KiB
C
118 lines
4.5 KiB
C
/*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVCODEC_CBS_INTERNAL_H
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#define AVCODEC_CBS_INTERNAL_H
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#include "avcodec.h"
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#include "cbs.h"
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#include "get_bits.h"
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#include "put_bits.h"
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typedef struct CodedBitstreamType {
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enum AVCodecID codec_id;
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size_t priv_data_size;
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// Split frag->data into coded bitstream units, creating the
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// frag->units array. Fill data but not content on each unit.
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// The header argument should be set if the fragment came from
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// a header block, which may require different parsing for some
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// codecs (e.g. the AVCC header in H.264).
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int (*split_fragment)(CodedBitstreamContext *ctx,
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CodedBitstreamFragment *frag,
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int header);
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// Read the unit->data bitstream and decompose it, creating
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// unit->content.
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int (*read_unit)(CodedBitstreamContext *ctx,
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CodedBitstreamUnit *unit);
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// Write the data bitstream from unit->content into pbc.
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// Return value AVERROR(ENOSPC) indicates that pbc was too small.
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int (*write_unit)(CodedBitstreamContext *ctx,
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CodedBitstreamUnit *unit,
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PutBitContext *pbc);
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// Read the data from all of frag->units and assemble it into
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// a bitstream for the whole fragment.
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int (*assemble_fragment)(CodedBitstreamContext *ctx,
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CodedBitstreamFragment *frag);
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// Free the codec internal state.
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void (*close)(CodedBitstreamContext *ctx);
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} CodedBitstreamType;
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// Helper functions for trace output.
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void ff_cbs_trace_header(CodedBitstreamContext *ctx,
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const char *name);
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void ff_cbs_trace_syntax_element(CodedBitstreamContext *ctx, int position,
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const char *name, const int *subscripts,
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const char *bitstring, int64_t value);
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// Helper functions for read/write of common bitstream elements, including
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// generation of trace output.
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int ff_cbs_read_unsigned(CodedBitstreamContext *ctx, GetBitContext *gbc,
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int width, const char *name,
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const int *subscripts, uint32_t *write_to,
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uint32_t range_min, uint32_t range_max);
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int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
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int width, const char *name,
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const int *subscripts, uint32_t value,
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uint32_t range_min, uint32_t range_max);
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int ff_cbs_read_signed(CodedBitstreamContext *ctx, GetBitContext *gbc,
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int width, const char *name,
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const int *subscripts, int32_t *write_to,
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int32_t range_min, int32_t range_max);
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int ff_cbs_write_signed(CodedBitstreamContext *ctx, PutBitContext *pbc,
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int width, const char *name,
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const int *subscripts, int32_t value,
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int32_t range_min, int32_t range_max);
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// The largest unsigned value representable in N bits, suitable for use as
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// range_max in the above functions.
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#define MAX_UINT_BITS(length) ((UINT64_C(1) << (length)) - 1)
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// The largest signed value representable in N bits, suitable for use as
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// range_max in the above functions.
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#define MAX_INT_BITS(length) ((INT64_C(1) << ((length) - 1)) - 1)
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// The smallest signed value representable in N bits, suitable for use as
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// range_min in the above functions.
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#define MIN_INT_BITS(length) (-(INT64_C(1) << ((length) - 1)))
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extern const CodedBitstreamType ff_cbs_type_av1;
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extern const CodedBitstreamType ff_cbs_type_h264;
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extern const CodedBitstreamType ff_cbs_type_h265;
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extern const CodedBitstreamType ff_cbs_type_jpeg;
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extern const CodedBitstreamType ff_cbs_type_mpeg2;
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extern const CodedBitstreamType ff_cbs_type_vp9;
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#endif /* AVCODEC_CBS_INTERNAL_H */
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