mirror of https://git.ffmpeg.org/ffmpeg.git
381 lines
9.9 KiB
C
381 lines
9.9 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_vp8.h"
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#include <stdbool.h>
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#define DEFAULT_PROB 0x80
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// The probability table is defined in 'vp8data.c'.
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extern const uint8_t ff_vp8_token_update_probs[4][8][3][11];
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// Implements VP8 boolean decoder using GetBitContext to read the bitstream.
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typedef struct CBSVP8BoolDecoder {
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GetBitContext *gbc;
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uint8_t value;
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uint8_t range;
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uint8_t count; // Store the number of bits in the `value` buffer.
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} CBSVP8BoolDecoder;
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static int cbs_vp8_bool_decoder_init(CBSVP8BoolDecoder *decoder, GetBitContext *gbc)
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{
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av_assert0(decoder);
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av_assert0(gbc);
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decoder->gbc = gbc;
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decoder->value = 0;
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decoder->range = 255;
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decoder->count = 0;
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return 0;
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}
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static bool cbs_vp8_bool_decoder_fill_value(CBSVP8BoolDecoder *decoder)
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{
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int bits = 8 - decoder->count;
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av_assert0(decoder->count <= 8);
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if (decoder->count == 8) {
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return true;
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}
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if (get_bits_left(decoder->gbc) >= bits) {
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decoder->value |= get_bits(decoder->gbc, bits);
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decoder->count += bits;
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}
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return (decoder->count == 8);
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}
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static int cbs_vp8_bool_decoder_read_bool(CBSVP8BoolDecoder *decoder,
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const uint8_t prob, uint8_t *output)
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{
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uint8_t split = 1 + (((decoder->range - 1) * prob) >> 8);
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if (!cbs_vp8_bool_decoder_fill_value(decoder)) {
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return AVERROR_INVALIDDATA;
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}
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av_assert0(decoder->count == 8);
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if (decoder->value >= split) {
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*output = 1;
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decoder->range -= split;
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decoder->value -= split;
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} else {
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*output = 0;
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decoder->range = split;
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}
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while (decoder->range < 128) {
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decoder->value <<= 1;
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decoder->range <<= 1;
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--decoder->count;
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}
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return 0;
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}
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static int cbs_vp8_bool_decoder_read_literal(CBSVP8BoolDecoder *decoder,
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const uint8_t prob,
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uint32_t num_bits,
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uint32_t *output)
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{
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int ret = 0;
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av_assert0(num_bits <= 32);
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*output = 0;
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for (; num_bits > 0; --num_bits) {
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uint8_t bit_output = 0;
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if ((ret = cbs_vp8_bool_decoder_read_bool(decoder, prob,
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&bit_output)) != 0) {
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return ret;
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}
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*output = (*output << 1) | bit_output;
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}
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return 0;
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}
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static int cbs_vp8_bool_decoder_read_unsigned(
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CodedBitstreamContext *ctx, CBSVP8BoolDecoder *bool_decoder, int width,
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uint8_t prob, const char *name, const int *subscripts, uint32_t *write_to,
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bool trace_enable)
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{
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int ret = 0;
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GetBitContext *gbc = bool_decoder->gbc;
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uint32_t value;
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CBS_TRACE_READ_START();
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av_assert0(width >= 0 && width <= 8);
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ret = cbs_vp8_bool_decoder_read_literal(bool_decoder, prob, width, &value);
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if (ret != 0) {
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return ret;
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}
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if (trace_enable) {
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CBS_TRACE_READ_END();
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}
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*write_to = value;
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return 0;
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}
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static int cbs_vp8_bool_decoder_read_signed(
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CodedBitstreamContext *ctx, CBSVP8BoolDecoder *bool_decoder, int width,
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uint8_t prob, const char *name, const int *subscripts, int32_t *write_to)
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{
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int ret = 0;
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GetBitContext *gbc = bool_decoder->gbc;
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int32_t value;
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uint8_t sign = 0;
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CBS_TRACE_READ_START();
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av_assert0(width >= 0 && width <= 8);
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ret = cbs_vp8_bool_decoder_read_literal(bool_decoder, prob, width, &value);
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if (ret != 0) {
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return ret;
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}
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ret = cbs_vp8_bool_decoder_read_bool(bool_decoder, prob, &sign);
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if (ret != 0) {
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return ret;
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}
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if (sign) {
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value = -value;
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}
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CBS_TRACE_READ_END();
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*write_to = value;
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return 0;
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}
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static int cbs_vp8_read_unsigned_le(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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{
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int32_t value;
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CBS_TRACE_READ_START();
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av_assert0(width > 0 && width <= 24);
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if (get_bits_left(gbc) < width) {
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av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid value: bitstream ended.\n");
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return AVERROR_INVALIDDATA;
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}
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value = get_bits_le(gbc, width);
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CBS_TRACE_READ_END();
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*write_to = value;
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return 0;
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}
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#define HEADER(name) \
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do { \
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ff_cbs_trace_header(ctx, name); \
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} while (0)
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#define CHECK(call) \
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do { \
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int 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_VP8(rw, name) FUNC_NAME(rw, vp8, name)
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#define FUNC(name) FUNC_VP8(READWRITE, name)
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#define SUBSCRIPTS(subs, ...) \
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(subs > 0 ? ((int[subs + 1]){subs, __VA_ARGS__}) : NULL)
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#define f(width, name) xf(width, name, 0)
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// bool [de|en]coder methods.
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#define bc_f(width, name) bc_unsigned_subs(width, DEFAULT_PROB, true, name, 0)
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#define bc_s(width, name) bc_signed_subs(width, DEFAULT_PROB, name, 0)
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#define bc_fs(width, name, subs, ...) \
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bc_unsigned_subs(width, DEFAULT_PROB, true, name, subs, __VA_ARGS__)
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#define bc_ss(width, name, subs, ...) \
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bc_signed_subs(width, DEFAULT_PROB, name, subs, __VA_ARGS__)
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// bool [de|en]coder methods for boolean value and disable tracing.
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#define bc_b(name) bc_unsigned_subs(1, DEFAULT_PROB, false, name, 0)
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#define bc_b_prob(prob, name) bc_unsigned_subs(1, prob, false, name, 0)
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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 CBSVP8BoolCodingRW CBSVP8BoolDecoder
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#define xf(width, name, subs, ...) \
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do { \
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uint32_t value; \
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CHECK(cbs_vp8_read_unsigned_le(ctx, rw, width, #name, \
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SUBSCRIPTS(subs, __VA_ARGS__), &value)); \
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current->name = value; \
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} while (0)
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#define fixed(width, name, value) \
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do { \
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uint32_t fixed_value; \
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CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, 0, &fixed_value, \
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value, value)); \
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} while (0)
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#define bc_unsigned_subs(width, prob, enable_trace, name, subs, ...) \
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do { \
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uint32_t value; \
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CHECK(cbs_vp8_bool_decoder_read_unsigned( \
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ctx, bool_coding_rw, width, prob, #name, \
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SUBSCRIPTS(subs, __VA_ARGS__), &value, enable_trace)); \
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current->name = value; \
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} while (0)
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#define bc_signed_subs(width, prob, name, subs, ...) \
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do { \
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int32_t value; \
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CHECK(cbs_vp8_bool_decoder_read_signed( \
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ctx, bool_coding_rw, width, prob, #name, \
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SUBSCRIPTS(subs, __VA_ARGS__), &value)); \
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current->name = value; \
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} while (0)
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#include "cbs_vp8_syntax_template.c"
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static int cbs_vp8_split_fragment(CodedBitstreamContext *ctx,
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CodedBitstreamFragment *frag, int header)
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{
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int err;
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if (frag->data_size == 0)
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return AVERROR_INVALIDDATA;
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err = ff_cbs_append_unit_data(frag, 0, frag->data, frag->data_size,
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frag->data_ref);
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if (err < 0)
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return err;
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return 0;
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}
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static int cbs_vp8_read_unit(CodedBitstreamContext *ctx,
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CodedBitstreamUnit *unit)
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{
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VP8RawFrame *frame;
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GetBitContext gbc;
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CBSVP8BoolDecoder bool_decoder;
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int err, pos;
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err = ff_cbs_alloc_unit_content(ctx, unit);
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if (err < 0)
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return err;
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frame = unit->content;
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// Create GetBitContext for uncompressed header.
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err = init_get_bits8_le(&gbc, unit->data, unit->data_size);
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if (err < 0)
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return err;
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err = cbs_vp8_read_uncompressed_header(ctx, &gbc, frame);
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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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av_assert0(pos % 8 == 0);
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// Create boolean decoder for compressed header.
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err = cbs_vp8_bool_decoder_init(&bool_decoder, &gbc);
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if (err < 0)
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return err;
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err = cbs_vp8_read_compressed_header(ctx, &bool_decoder, frame);
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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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pos /= 8;
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av_assert0(pos <= unit->data_size);
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frame->data_ref = av_buffer_ref(unit->data_ref);
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if (!frame->data_ref)
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return AVERROR(ENOMEM);
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frame->data = unit->data + pos;
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frame->data_size = unit->data_size - pos;
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return 0;
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}
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static int cbs_vp8_write_unit(CodedBitstreamContext *ctx,
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CodedBitstreamUnit *unit, PutBitContext *pbc)
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{
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return AVERROR_PATCHWELCOME;
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}
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static int cbs_vp8_assemble_fragment(CodedBitstreamContext *ctx,
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CodedBitstreamFragment *frag)
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{
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return AVERROR_PATCHWELCOME;
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}
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static void cbs_vp8_flush(CodedBitstreamContext *ctx)
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{
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// Do nothing.
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}
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static const CodedBitstreamUnitTypeDescriptor cbs_vp8_unit_types[] = {
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CBS_UNIT_TYPE_INTERNAL_REF(0, VP8RawFrame, data),
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CBS_UNIT_TYPE_END_OF_LIST,
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};
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const CodedBitstreamType ff_cbs_type_vp8 = {
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.codec_id = AV_CODEC_ID_VP8,
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.priv_data_size = 0,
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.unit_types = cbs_vp8_unit_types,
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.split_fragment = &cbs_vp8_split_fragment,
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.read_unit = &cbs_vp8_read_unit,
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.write_unit = &cbs_vp8_write_unit,
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.flush = &cbs_vp8_flush,
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.assemble_fragment = &cbs_vp8_assemble_fragment,
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};
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