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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 Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/common.h"
#include "golomb.h"
#include "hevc.h"
#include "h2645_parse.h"
#include "parser.h"
#define START_CODE 0x000001 ///< start_code_prefix_one_3bytes
#define IS_IRAP_NAL(nal) (nal->type >= 16 && nal->type <= 23)
typedef struct HEVCParserContext {
ParseContext pc;
H2645Packet pkt;
HEVCParamSets ps;
int parsed_extradata;
} HEVCParserContext;
static int hevc_parse_slice_header(AVCodecParserContext *s, H2645NAL *nal,
AVCodecContext *avctx)
{
HEVCParserContext *ctx = s->priv_data;
GetBitContext *gb = &nal->gb;
HEVCPPS *pps;
HEVCSPS *sps;
unsigned int pps_id;
get_bits1(gb); // first slice in pic
if (IS_IRAP_NAL(nal))
get_bits1(gb); // no output of prior pics
pps_id = get_ue_golomb_long(gb);
if (pps_id >= MAX_PPS_COUNT || !ctx->ps.pps_list[pps_id]) {
av_log(avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", pps_id);
return AVERROR_INVALIDDATA;
}
pps = (HEVCPPS*)ctx->ps.pps_list[pps_id]->data;
sps = (HEVCSPS*)ctx->ps.sps_list[pps->sps_id]->data;
/* export the stream parameters */
s->coded_width = sps->width;
s->coded_height = sps->height;
s->width = sps->output_width;
s->height = sps->output_height;
s->format = sps->pix_fmt;
avctx->profile = sps->ptl.general_ptl.profile_idc;
avctx->level = sps->ptl.general_ptl.level_idc;
/* ignore the rest for now*/
return 0;
}
static int parse_nal_units(AVCodecParserContext *s, const uint8_t *buf,
int buf_size, AVCodecContext *avctx)
{
HEVCParserContext *ctx = s->priv_data;
int ret, i;
ret = ff_h2645_packet_split(&ctx->pkt, buf, buf_size, avctx, 0, 0,
AV_CODEC_ID_HEVC);
if (ret < 0)
return ret;
for (i = 0; i < ctx->pkt.nb_nals; i++) {
H2645NAL *nal = &ctx->pkt.nals[i];
/* ignore everything except parameter sets and VCL NALUs */
switch (nal->type) {
case NAL_VPS: ff_hevc_decode_nal_vps(&nal->gb, avctx, &ctx->ps); break;
case NAL_SPS: ff_hevc_decode_nal_sps(&nal->gb, avctx, &ctx->ps, 1); break;
case NAL_PPS: ff_hevc_decode_nal_pps(&nal->gb, avctx, &ctx->ps); break;
case NAL_TRAIL_R:
case NAL_TRAIL_N:
case NAL_TSA_N:
case NAL_TSA_R:
case NAL_STSA_N:
case NAL_STSA_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:
case NAL_RADL_N:
case NAL_RADL_R:
case NAL_RASL_N:
case NAL_RASL_R: hevc_parse_slice_header(s, nal, avctx); break;
}
}
return 0;
}
/**
* 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)
{
HEVCParserContext *ctx = s->priv_data;
ParseContext *pc = &ctx->pc;
int i;
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;
s->key_frame = nut >= NAL_BLA_W_LP && nut <= NAL_CRA_NUT;
} else { // First slice of next frame found
pc->frame_start_found = 0;
return i - 5;
}
}
}
}
return END_NOT_FOUND;
}
static int hevc_parse(AVCodecParserContext *s, AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
int next;
HEVCParserContext *ctx = s->priv_data;
ParseContext *pc = &ctx->pc;
if (avctx->extradata && !ctx->parsed_extradata) {
parse_nal_units(s, avctx->extradata, avctx->extradata_size, avctx);
ctx->parsed_extradata = 1;
}
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, buf, buf_size, avctx);
*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 void hevc_parser_close(AVCodecParserContext *s)
{
HEVCParserContext *ctx = s->priv_data;
int i;
for (i = 0; i < FF_ARRAY_ELEMS(ctx->ps.vps_list); i++)
av_buffer_unref(&ctx->ps.vps_list[i]);
for (i = 0; i < FF_ARRAY_ELEMS(ctx->ps.sps_list); i++)
av_buffer_unref(&ctx->ps.sps_list[i]);
for (i = 0; i < FF_ARRAY_ELEMS(ctx->ps.pps_list); i++)
av_buffer_unref(&ctx->ps.pps_list[i]);
ff_h2645_packet_uninit(&ctx->pkt);
av_freep(&ctx->pc.buffer);
}
AVCodecParser ff_hevc_parser = {
.codec_ids = { AV_CODEC_ID_HEVC },
.priv_data_size = sizeof(HEVCParserContext),
.parser_parse = hevc_parse,
.parser_close = hevc_parser_close,
.split = hevc_split,
};