346 lines
11 KiB
C
346 lines
11 KiB
C
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/*
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* HEVC Annex B format parser
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*
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* Copyright (C) 2012 - 2013 Guillaume Martres
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*
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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/common.h"
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#include "parser.h"
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#include "hevc.h"
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#include "golomb.h"
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#define START_CODE 0x000001 ///< start_code_prefix_one_3bytes
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typedef struct HEVCParseContext {
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HEVCContext h;
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ParseContext pc;
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} HEVCParseContext;
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/**
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* Find the end of the current frame in the bitstream.
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* @return the position of the first byte of the next frame, or END_NOT_FOUND
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*/
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static int hevc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf, int buf_size)
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{
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int i;
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ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
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for (i = 0; i < buf_size; i++) {
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int nut;
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pc->state64 = (pc->state64 << 8) | buf[i];
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if (((pc->state64 >> 3 * 8) & 0xFFFFFF) != START_CODE)
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continue;
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nut = (pc->state64 >> 2 * 8 + 1) & 0x3F;
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// Beginning of access unit
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if ((nut >= NAL_VPS && nut <= NAL_AUD) || nut == NAL_SEI_PREFIX ||
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(nut >= 41 && nut <= 44) || (nut >= 48 && nut <= 55)) {
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if (pc->frame_start_found) {
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pc->frame_start_found = 0;
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return i - 5;
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}
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} else if (nut <= NAL_RASL_R ||
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(nut >= NAL_BLA_W_LP && nut <= NAL_CRA_NUT)) {
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int first_slice_segment_in_pic_flag = buf[i] >> 7;
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if (first_slice_segment_in_pic_flag) {
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if (!pc->frame_start_found) {
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pc->frame_start_found = 1;
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} else { // First slice of next frame found
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pc->frame_start_found = 0;
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return i - 5;
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}
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}
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}
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}
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return END_NOT_FOUND;
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}
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/**
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* Parse NAL units of found picture and decode some basic information.
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*
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* @param s parser context.
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* @param avctx codec context.
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* @param buf buffer with field/frame data.
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* @param buf_size size of the buffer.
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*/
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static inline int parse_nal_units(AVCodecParserContext *s,
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AVCodecContext *avctx,
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const uint8_t *buf, int buf_size)
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{
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HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
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GetBitContext *gb = &h->HEVClc->gb;
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SliceHeader *sh = &h->sh;
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const uint8_t *buf_end = buf + buf_size;
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int state = -1, i;
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HEVCNAL *nal;
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/* set some sane default values */
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s->pict_type = AV_PICTURE_TYPE_I;
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s->key_frame = 0;
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s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
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h->avctx = avctx;
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if (!buf_size)
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return 0;
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if (h->nals_allocated < 1) {
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HEVCNAL *tmp = av_realloc_array(h->nals, 1, sizeof(*tmp));
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if (!tmp)
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return AVERROR(ENOMEM);
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h->nals = tmp;
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memset(h->nals, 0, sizeof(*tmp));
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h->nals_allocated = 1;
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}
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nal = &h->nals[0];
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for (;;) {
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int src_length, consumed;
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buf = avpriv_find_start_code(buf, buf_end, &state);
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if (--buf + 2 >= buf_end)
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break;
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src_length = buf_end - buf;
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h->nal_unit_type = (*buf >> 1) & 0x3f;
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h->temporal_id = (*(buf + 1) & 0x07) - 1;
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if (h->nal_unit_type <= NAL_CRA_NUT) {
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// Do not walk the whole buffer just to decode slice segment header
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if (src_length > 20)
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src_length = 20;
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}
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consumed = ff_hevc_extract_rbsp(h, buf, src_length, nal);
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if (consumed < 0)
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return consumed;
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init_get_bits8(gb, nal->data + 2, nal->size);
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switch (h->nal_unit_type) {
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case NAL_VPS:
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ff_hevc_decode_nal_vps(h);
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break;
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case NAL_SPS:
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ff_hevc_decode_nal_sps(h);
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break;
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case NAL_PPS:
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ff_hevc_decode_nal_pps(h);
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break;
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case NAL_SEI_PREFIX:
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case NAL_SEI_SUFFIX:
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ff_hevc_decode_nal_sei(h);
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break;
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case NAL_TRAIL_N:
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case NAL_TRAIL_R:
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case NAL_TSA_N:
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case NAL_TSA_R:
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case NAL_STSA_N:
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case NAL_STSA_R:
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case NAL_RADL_N:
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case NAL_RADL_R:
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case NAL_RASL_N:
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case NAL_RASL_R:
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case NAL_BLA_W_LP:
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case NAL_BLA_W_RADL:
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case NAL_BLA_N_LP:
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case NAL_IDR_W_RADL:
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case NAL_IDR_N_LP:
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case NAL_CRA_NUT:
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sh->first_slice_in_pic_flag = get_bits1(gb);
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if (h->nal_unit_type >= 16 && h->nal_unit_type <= 23) {
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s->key_frame = 1;
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sh->no_output_of_prior_pics_flag = get_bits1(gb);
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}
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sh->pps_id = get_ue_golomb(gb);
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if (sh->pps_id >= MAX_PPS_COUNT || !h->pps_list[sh->pps_id]) {
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av_log(h->avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", sh->pps_id);
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return AVERROR_INVALIDDATA;
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}
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h->pps = (HEVCPPS*)h->pps_list[sh->pps_id]->data;
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if (h->pps->sps_id >= MAX_SPS_COUNT || !h->sps_list[h->pps->sps_id]) {
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av_log(h->avctx, AV_LOG_ERROR, "SPS id out of range: %d\n", h->pps->sps_id);
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return AVERROR_INVALIDDATA;
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}
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if (h->sps != (HEVCSPS*)h->sps_list[h->pps->sps_id]->data) {
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h->sps = (HEVCSPS*)h->sps_list[h->pps->sps_id]->data;
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h->vps = h->vps_list[h->sps->vps_id];
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}
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if (!sh->first_slice_in_pic_flag) {
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int slice_address_length;
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if (h->pps->dependent_slice_segments_enabled_flag)
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sh->dependent_slice_segment_flag = get_bits1(gb);
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else
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sh->dependent_slice_segment_flag = 0;
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slice_address_length = av_ceil_log2_c(h->sps->ctb_width *
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h->sps->ctb_height);
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sh->slice_segment_addr = get_bits(gb, slice_address_length);
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if (sh->slice_segment_addr >= h->sps->ctb_width * h->sps->ctb_height) {
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av_log(h->avctx, AV_LOG_ERROR, "Invalid slice segment address: %u.\n",
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sh->slice_segment_addr);
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return AVERROR_INVALIDDATA;
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}
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} else
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sh->dependent_slice_segment_flag = 0;
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if (sh->dependent_slice_segment_flag)
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break;
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for (i = 0; i < h->pps->num_extra_slice_header_bits; i++)
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skip_bits(gb, 1); // slice_reserved_undetermined_flag[]
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sh->slice_type = get_ue_golomb(gb);
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if (!(sh->slice_type == I_SLICE || sh->slice_type == P_SLICE ||
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sh->slice_type == B_SLICE)) {
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av_log(h->avctx, AV_LOG_ERROR, "Unknown slice type: %d.\n",
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sh->slice_type);
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return AVERROR_INVALIDDATA;
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}
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s->pict_type = sh->slice_type == B_SLICE ? AV_PICTURE_TYPE_B :
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sh->slice_type == P_SLICE ? AV_PICTURE_TYPE_P :
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AV_PICTURE_TYPE_I;
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if (h->pps->output_flag_present_flag)
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sh->pic_output_flag = get_bits1(gb);
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if (h->sps->separate_colour_plane_flag)
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sh->colour_plane_id = get_bits(gb, 2);
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if (!IS_IDR(h)) {
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sh->pic_order_cnt_lsb = get_bits(gb, h->sps->log2_max_poc_lsb);
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s->output_picture_number = h->poc = ff_hevc_compute_poc(h, sh->pic_order_cnt_lsb);
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} else
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s->output_picture_number = h->poc = 0;
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if (h->temporal_id == 0 &&
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h->nal_unit_type != NAL_TRAIL_N &&
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h->nal_unit_type != NAL_TSA_N &&
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h->nal_unit_type != NAL_STSA_N &&
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h->nal_unit_type != NAL_RADL_N &&
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h->nal_unit_type != NAL_RASL_N &&
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h->nal_unit_type != NAL_RADL_R &&
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h->nal_unit_type != NAL_RASL_R)
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h->pocTid0 = h->poc;
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return 0; /* no need to evaluate the rest */
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}
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buf += consumed;
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}
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/* didn't find a picture! */
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av_log(h->avctx, AV_LOG_ERROR, "missing picture in access unit\n");
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return -1;
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}
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static int hevc_parse(AVCodecParserContext *s,
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AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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int next;
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ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
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if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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next = buf_size;
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} else {
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next = hevc_find_frame_end(s, buf, buf_size);
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if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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}
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parse_nal_units(s, avctx, buf, buf_size);
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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// Split after the parameter sets at the beginning of the stream if they exist.
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static int hevc_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
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{
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int i;
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uint32_t state = -1;
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int has_ps = 0;
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for (i = 0; i < buf_size; i++) {
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state = (state << 8) | buf[i];
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if (((state >> 8) & 0xFFFFFF) == START_CODE) {
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int nut = (state >> 1) & 0x3F;
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if (nut >= NAL_VPS && nut <= NAL_PPS) {
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has_ps = 1;
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} else if (has_ps) {
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return i - 3;
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} else { // no parameter set at the beginning of the stream
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return 0;
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}
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}
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}
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return 0;
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}
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static int hevc_init(AVCodecParserContext *s)
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{
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HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
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h->HEVClc = av_mallocz(sizeof(HEVCLocalContext));
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h->skipped_bytes_pos_size = INT_MAX;
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return 0;
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}
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static void hevc_close(AVCodecParserContext *s)
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{
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int i;
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HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
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ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
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av_freep(&h->skipped_bytes_pos);
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av_freep(&h->HEVClc);
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av_freep(&pc->buffer);
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for (i = 0; i < FF_ARRAY_ELEMS(h->vps_list); i++)
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av_freep(&h->vps_list[i]);
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for (i = 0; i < FF_ARRAY_ELEMS(h->sps_list); i++)
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av_buffer_unref(&h->sps_list[i]);
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for (i = 0; i < FF_ARRAY_ELEMS(h->pps_list); i++)
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av_buffer_unref(&h->pps_list[i]);
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for (i = 0; i < h->nals_allocated; i++)
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av_freep(&h->nals[i].rbsp_buffer);
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av_freep(&h->nals);
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h->nals_allocated = 0;
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}
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AVCodecParser ff_hevc_parser = {
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.codec_ids = { AV_CODEC_ID_HEVC },
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.priv_data_size = sizeof(HEVCParseContext),
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.parser_init = hevc_init,
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.parser_parse = hevc_parse,
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.parser_close = hevc_close,
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.split = hevc_split,
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};
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