mirror of https://git.ffmpeg.org/ffmpeg.git
431 lines
13 KiB
C
431 lines
13 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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#include "libavutil/avassert.h"
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#include "cbs.h"
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#include "cbs_internal.h"
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#include "cbs_mpeg2.h"
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#include "internal.h"
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#define HEADER(name) do { \
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ff_cbs_trace_header(ctx, name); \
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} while (0)
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#define CHECK(call) do { \
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err = (call); \
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if (err < 0) \
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return err; \
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} while (0)
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#define FUNC_NAME(rw, codec, name) cbs_ ## codec ## _ ## rw ## _ ## name
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#define FUNC_MPEG2(rw, name) FUNC_NAME(rw, mpeg2, name)
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#define FUNC(name) FUNC_MPEG2(READWRITE, name)
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#define SUBSCRIPTS(subs, ...) (subs > 0 ? ((int[subs + 1]){ subs, __VA_ARGS__ }) : NULL)
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#define ui(width, name) \
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xui(width, name, current->name, 0, MAX_UINT_BITS(width), 0)
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#define uir(width, name) \
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xui(width, name, current->name, 1, MAX_UINT_BITS(width), 0)
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#define uis(width, name, subs, ...) \
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xui(width, name, current->name, 0, MAX_UINT_BITS(width), subs, __VA_ARGS__)
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#define uirs(width, name, subs, ...) \
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xui(width, name, current->name, 1, MAX_UINT_BITS(width), subs, __VA_ARGS__)
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#define sis(width, name, subs, ...) \
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xsi(width, name, current->name, subs, __VA_ARGS__)
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#define READ
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#define READWRITE read
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#define RWContext GetBitContext
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#define xui(width, name, var, range_min, range_max, subs, ...) do { \
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uint32_t value = 0; \
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CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
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SUBSCRIPTS(subs, __VA_ARGS__), \
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&value, range_min, range_max)); \
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var = value; \
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} while (0)
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#define xsi(width, name, var, subs, ...) do { \
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int32_t value; \
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CHECK(ff_cbs_read_signed(ctx, rw, width, #name, \
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SUBSCRIPTS(subs, __VA_ARGS__), &value, \
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MIN_INT_BITS(width), \
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MAX_INT_BITS(width))); \
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var = value; \
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} while (0)
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#define marker_bit() do { \
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av_unused uint32_t one; \
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CHECK(ff_cbs_read_unsigned(ctx, rw, 1, "marker_bit", NULL, &one, 1, 1)); \
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} while (0)
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#define nextbits(width, compare, var) \
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(get_bits_left(rw) >= width && \
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(var = show_bits(rw, width)) == (compare))
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#include "cbs_mpeg2_syntax_template.c"
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#undef READ
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#undef READWRITE
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#undef RWContext
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#undef xui
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#undef xsi
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#undef marker_bit
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#undef nextbits
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#define WRITE
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#define READWRITE write
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#define RWContext PutBitContext
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#define xui(width, name, var, range_min, range_max, subs, ...) do { \
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CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
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SUBSCRIPTS(subs, __VA_ARGS__), \
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var, range_min, range_max)); \
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} while (0)
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#define xsi(width, name, var, subs, ...) do { \
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CHECK(ff_cbs_write_signed(ctx, rw, width, #name, \
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SUBSCRIPTS(subs, __VA_ARGS__), var, \
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MIN_INT_BITS(width), \
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MAX_INT_BITS(width))); \
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} while (0)
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#define marker_bit() do { \
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CHECK(ff_cbs_write_unsigned(ctx, rw, 1, "marker_bit", NULL, 1, 1, 1)); \
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} while (0)
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#define nextbits(width, compare, var) (var)
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#include "cbs_mpeg2_syntax_template.c"
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#undef READ
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#undef READWRITE
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#undef RWContext
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#undef xui
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#undef xsi
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#undef marker_bit
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#undef nextbits
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static void cbs_mpeg2_free_user_data(void *unit, uint8_t *content)
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{
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MPEG2RawUserData *user = (MPEG2RawUserData*)content;
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av_buffer_unref(&user->user_data_ref);
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av_freep(&content);
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}
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static void cbs_mpeg2_free_slice(void *unit, uint8_t *content)
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{
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MPEG2RawSlice *slice = (MPEG2RawSlice*)content;
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av_buffer_unref(&slice->header.extra_information_ref);
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av_buffer_unref(&slice->data_ref);
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av_freep(&content);
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}
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static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx,
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CodedBitstreamFragment *frag,
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int header)
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{
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const uint8_t *start, *end;
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uint8_t *unit_data;
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uint32_t start_code = -1, next_start_code = -1;
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size_t unit_size;
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int err, i, unit_type;
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start = avpriv_find_start_code(frag->data, frag->data + frag->data_size,
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&start_code);
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for (i = 0;; i++) {
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end = avpriv_find_start_code(start, frag->data + frag->data_size,
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&next_start_code);
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unit_type = start_code & 0xff;
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// The start and end pointers point at to the byte following the
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// start_code_identifier in the start code that they found.
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if (end == frag->data + frag->data_size) {
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// We didn't find a start code, so this is the final unit.
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unit_size = end - (start - 1);
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} else {
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// Unit runs from start to the beginning of the start code
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// pointed to by end (including any padding zeroes).
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unit_size = (end - 4) - (start - 1);
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}
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unit_data = (uint8_t *)start - 1;
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err = ff_cbs_insert_unit_data(ctx, frag, i, unit_type,
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unit_data, unit_size, frag->data_ref);
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if (err < 0)
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return err;
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if (end == frag->data + frag->data_size)
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break;
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start_code = next_start_code;
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start = end;
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}
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return 0;
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}
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static int cbs_mpeg2_read_unit(CodedBitstreamContext *ctx,
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CodedBitstreamUnit *unit)
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{
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GetBitContext gbc;
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int err;
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err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
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if (err < 0)
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return err;
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if (MPEG2_START_IS_SLICE(unit->type)) {
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MPEG2RawSlice *slice;
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int pos, len;
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err = ff_cbs_alloc_unit_content(ctx, unit, sizeof(*slice),
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&cbs_mpeg2_free_slice);
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if (err < 0)
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return err;
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slice = unit->content;
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err = cbs_mpeg2_read_slice_header(ctx, &gbc, &slice->header);
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if (err < 0)
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return err;
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pos = get_bits_count(&gbc);
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len = unit->data_size;
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slice->data_size = len - pos / 8;
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slice->data_ref = av_buffer_ref(unit->data_ref);
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if (!slice->data_ref)
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return AVERROR(ENOMEM);
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slice->data = unit->data + pos / 8;
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slice->data_bit_start = pos % 8;
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} else {
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switch (unit->type) {
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#define START(start_code, type, read_func, free_func) \
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case start_code: \
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{ \
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type *header; \
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err = ff_cbs_alloc_unit_content(ctx, unit, \
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sizeof(*header), free_func); \
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if (err < 0) \
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return err; \
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header = unit->content; \
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err = cbs_mpeg2_read_ ## read_func(ctx, &gbc, header); \
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if (err < 0) \
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return err; \
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} \
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break;
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START(0x00, MPEG2RawPictureHeader, picture_header, NULL);
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START(0xb2, MPEG2RawUserData, user_data,
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&cbs_mpeg2_free_user_data);
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START(0xb3, MPEG2RawSequenceHeader, sequence_header, NULL);
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START(0xb5, MPEG2RawExtensionData, extension_data, NULL);
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START(0xb8, MPEG2RawGroupOfPicturesHeader,
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group_of_pictures_header, NULL);
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#undef START
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default:
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av_log(ctx->log_ctx, AV_LOG_ERROR, "Unknown start code %02"PRIx32".\n",
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unit->type);
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return AVERROR_INVALIDDATA;
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}
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}
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return 0;
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}
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static int cbs_mpeg2_write_header(CodedBitstreamContext *ctx,
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CodedBitstreamUnit *unit,
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PutBitContext *pbc)
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{
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int err;
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switch (unit->type) {
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#define START(start_code, type, func) \
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case start_code: \
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err = cbs_mpeg2_write_ ## func(ctx, pbc, unit->content); \
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break;
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START(0x00, MPEG2RawPictureHeader, picture_header);
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START(0xb2, MPEG2RawUserData, user_data);
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START(0xb3, MPEG2RawSequenceHeader, sequence_header);
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START(0xb5, MPEG2RawExtensionData, extension_data);
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START(0xb8, MPEG2RawGroupOfPicturesHeader, group_of_pictures_header);
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#undef START
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default:
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av_log(ctx->log_ctx, AV_LOG_ERROR, "Write unimplemented for start "
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"code %02"PRIx32".\n", unit->type);
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return AVERROR_PATCHWELCOME;
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}
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return err;
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}
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static int cbs_mpeg2_write_slice(CodedBitstreamContext *ctx,
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CodedBitstreamUnit *unit,
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PutBitContext *pbc)
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{
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MPEG2RawSlice *slice = unit->content;
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GetBitContext gbc;
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size_t bits_left;
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int err;
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err = cbs_mpeg2_write_slice_header(ctx, pbc, &slice->header);
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if (err < 0)
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return err;
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if (slice->data) {
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if (slice->data_size * 8 + 8 > put_bits_left(pbc))
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return AVERROR(ENOSPC);
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init_get_bits(&gbc, slice->data, slice->data_size * 8);
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skip_bits_long(&gbc, slice->data_bit_start);
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while (get_bits_left(&gbc) > 15)
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put_bits(pbc, 16, get_bits(&gbc, 16));
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bits_left = get_bits_left(&gbc);
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put_bits(pbc, bits_left, get_bits(&gbc, bits_left));
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// Align with zeroes.
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while (put_bits_count(pbc) % 8 != 0)
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put_bits(pbc, 1, 0);
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}
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return 0;
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}
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static int cbs_mpeg2_write_unit(CodedBitstreamContext *ctx,
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CodedBitstreamUnit *unit)
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{
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CodedBitstreamMPEG2Context *priv = ctx->priv_data;
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PutBitContext pbc;
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int err;
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if (!priv->write_buffer) {
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// Initial write buffer size is 1MB.
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priv->write_buffer_size = 1024 * 1024;
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reallocate_and_try_again:
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err = av_reallocp(&priv->write_buffer, priv->write_buffer_size);
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if (err < 0) {
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av_log(ctx->log_ctx, AV_LOG_ERROR, "Unable to allocate a "
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"sufficiently large write buffer (last attempt "
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"%"SIZE_SPECIFIER" bytes).\n", priv->write_buffer_size);
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return err;
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}
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}
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init_put_bits(&pbc, priv->write_buffer, priv->write_buffer_size);
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if (unit->type >= 0x01 && unit->type <= 0xaf)
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err = cbs_mpeg2_write_slice(ctx, unit, &pbc);
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else
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err = cbs_mpeg2_write_header(ctx, unit, &pbc);
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if (err == AVERROR(ENOSPC)) {
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// Overflow.
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priv->write_buffer_size *= 2;
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goto reallocate_and_try_again;
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}
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if (err < 0) {
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// Write failed for some other reason.
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return err;
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}
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if (put_bits_count(&pbc) % 8)
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unit->data_bit_padding = 8 - put_bits_count(&pbc) % 8;
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else
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unit->data_bit_padding = 0;
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unit->data_size = (put_bits_count(&pbc) + 7) / 8;
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flush_put_bits(&pbc);
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err = ff_cbs_alloc_unit_data(ctx, unit, unit->data_size);
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if (err < 0)
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return err;
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memcpy(unit->data, priv->write_buffer, unit->data_size);
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return 0;
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}
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static int cbs_mpeg2_assemble_fragment(CodedBitstreamContext *ctx,
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CodedBitstreamFragment *frag)
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{
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uint8_t *data;
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size_t size, dp;
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int i;
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size = 0;
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for (i = 0; i < frag->nb_units; i++)
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size += 3 + frag->units[i].data_size;
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frag->data_ref = av_buffer_alloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
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if (!frag->data_ref)
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return AVERROR(ENOMEM);
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data = frag->data_ref->data;
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dp = 0;
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for (i = 0; i < frag->nb_units; i++) {
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CodedBitstreamUnit *unit = &frag->units[i];
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data[dp++] = 0;
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data[dp++] = 0;
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data[dp++] = 1;
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memcpy(data + dp, unit->data, unit->data_size);
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dp += unit->data_size;
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}
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av_assert0(dp == size);
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memset(data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
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frag->data = data;
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frag->data_size = size;
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return 0;
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}
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static void cbs_mpeg2_close(CodedBitstreamContext *ctx)
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{
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CodedBitstreamMPEG2Context *priv = ctx->priv_data;
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av_freep(&priv->write_buffer);
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}
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const CodedBitstreamType ff_cbs_type_mpeg2 = {
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.codec_id = AV_CODEC_ID_MPEG2VIDEO,
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.priv_data_size = sizeof(CodedBitstreamMPEG2Context),
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.split_fragment = &cbs_mpeg2_split_fragment,
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.read_unit = &cbs_mpeg2_read_unit,
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.write_unit = &cbs_mpeg2_write_unit,
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.assemble_fragment = &cbs_mpeg2_assemble_fragment,
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.close = &cbs_mpeg2_close,
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};
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