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ffmpeg/libavcodec/hevc_parser.c

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