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FFmpeg/libavcodec/hevc_parser.c
Andreas Rheinhardt cbb6ba2e86 avcodec/cavsdec, h264*, hevc_parser: Use get_ue_golomb_31 where possible 
instead of get_ue_golomb(). The difference between the two is that the
latter also has to take into account the case in which the read code is
more than 9 bits (four preceding zeroes + at most five value bits) long,
leading to more code.

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2020-07-29 05:11:54 +02:00

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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 "golomb.h"
#include "hevc.h"
#include "hevc_parse.h"
#include "hevc_ps.h"
#include "hevc_sei.h"
#include "h2645_parse.h"
#include "internal.h"
#include "parser.h"
#define START_CODE 0x000001 ///< start_code_prefix_one_3bytes
#define IS_IRAP_NAL(nal) (nal->type >= 16 && nal->type <= 23)
#define IS_IDR_NAL(nal) (nal->type == HEVC_NAL_IDR_W_RADL || nal->type == HEVC_NAL_IDR_N_LP)
typedef struct HEVCParserContext {
ParseContext pc;
H2645Packet pkt;
HEVCParamSets ps;
HEVCSEI sei;
int is_avc;
int nal_length_size;
int parsed_extradata;
int poc;
int pocTid0;
} HEVCParserContext;
static int hevc_parse_slice_header(AVCodecParserContext *s, H2645NAL *nal,
AVCodecContext *avctx)
{
HEVCParserContext *ctx = s->priv_data;
HEVCParamSets *ps = &ctx->ps;
HEVCSEI *sei = &ctx->sei;
GetBitContext *gb = &nal->gb;
const HEVCWindow *ow;
int i, num = 0, den = 0;
unsigned int pps_id, first_slice_in_pic_flag, dependent_slice_segment_flag;
enum HEVCSliceType slice_type;
first_slice_in_pic_flag = get_bits1(gb);
s->picture_structure = sei->picture_timing.picture_struct;
s->field_order = sei->picture_timing.picture_struct;
if (IS_IRAP_NAL(nal)) {
s->key_frame = 1;
skip_bits1(gb); // no_output_of_prior_pics_flag
}
pps_id = get_ue_golomb(gb);
if (pps_id >= HEVC_MAX_PPS_COUNT || !ps->pps_list[pps_id]) {
av_log(avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", pps_id);
return AVERROR_INVALIDDATA;
}
ps->pps = (HEVCPPS*)ps->pps_list[pps_id]->data;
if (ps->pps->sps_id >= HEVC_MAX_SPS_COUNT || !ps->sps_list[ps->pps->sps_id]) {
av_log(avctx, AV_LOG_ERROR, "SPS id out of range: %d\n", ps->pps->sps_id);
return AVERROR_INVALIDDATA;
}
if (ps->sps != (HEVCSPS*)ps->sps_list[ps->pps->sps_id]->data) {
ps->sps = (HEVCSPS*)ps->sps_list[ps->pps->sps_id]->data;
ps->vps = (HEVCVPS*)ps->vps_list[ps->sps->vps_id]->data;
}
ow = &ps->sps->output_window;
s->coded_width = ps->sps->width;
s->coded_height = ps->sps->height;
s->width = ps->sps->width - ow->left_offset - ow->right_offset;
s->height = ps->sps->height - ow->top_offset - ow->bottom_offset;
s->format = ps->sps->pix_fmt;
avctx->profile = ps->sps->ptl.general_ptl.profile_idc;
avctx->level = ps->sps->ptl.general_ptl.level_idc;
if (ps->vps->vps_timing_info_present_flag) {
num = ps->vps->vps_num_units_in_tick;
den = ps->vps->vps_time_scale;
} else if (ps->sps->vui.vui_timing_info_present_flag) {
num = ps->sps->vui.vui_num_units_in_tick;
den = ps->sps->vui.vui_time_scale;
}
if (num != 0 && den != 0)
av_reduce(&avctx->framerate.den, &avctx->framerate.num,
num, den, 1 << 30);
if (!first_slice_in_pic_flag) {
unsigned int slice_segment_addr;
int slice_address_length;
if (ps->pps->dependent_slice_segments_enabled_flag)
dependent_slice_segment_flag = get_bits1(gb);
else
dependent_slice_segment_flag = 0;
slice_address_length = av_ceil_log2_c(ps->sps->ctb_width *
ps->sps->ctb_height);
slice_segment_addr = get_bitsz(gb, slice_address_length);
if (slice_segment_addr >= ps->sps->ctb_width * ps->sps->ctb_height) {
av_log(avctx, AV_LOG_ERROR, "Invalid slice segment address: %u.\n",
slice_segment_addr);
return AVERROR_INVALIDDATA;
}
} else
dependent_slice_segment_flag = 0;
if (dependent_slice_segment_flag)
return 0; /* break; */
for (i = 0; i < ps->pps->num_extra_slice_header_bits; i++)
skip_bits(gb, 1); // slice_reserved_undetermined_flag[]
slice_type = get_ue_golomb_31(gb);
if (!(slice_type == HEVC_SLICE_I || slice_type == HEVC_SLICE_P ||
slice_type == HEVC_SLICE_B)) {
av_log(avctx, AV_LOG_ERROR, "Unknown slice type: %d.\n",
slice_type);
return AVERROR_INVALIDDATA;
}
s->pict_type = slice_type == HEVC_SLICE_B ? AV_PICTURE_TYPE_B :
slice_type == HEVC_SLICE_P ? AV_PICTURE_TYPE_P :
AV_PICTURE_TYPE_I;
if (ps->pps->output_flag_present_flag)
skip_bits1(gb); // pic_output_flag
if (ps->sps->separate_colour_plane_flag)
skip_bits(gb, 2); // colour_plane_id
if (!IS_IDR_NAL(nal)) {
int pic_order_cnt_lsb = get_bits(gb, ps->sps->log2_max_poc_lsb);
s->output_picture_number = ctx->poc =
ff_hevc_compute_poc(ps->sps, ctx->pocTid0, pic_order_cnt_lsb, nal->type);
} else
s->output_picture_number = ctx->poc = 0;
if (nal->temporal_id == 0 &&
nal->type != HEVC_NAL_TRAIL_N &&
nal->type != HEVC_NAL_TSA_N &&
nal->type != HEVC_NAL_STSA_N &&
nal->type != HEVC_NAL_RADL_N &&
nal->type != HEVC_NAL_RASL_N &&
nal->type != HEVC_NAL_RADL_R &&
nal->type != HEVC_NAL_RASL_R)
ctx->pocTid0 = ctx->poc;
return 1; /* no need to evaluate the rest */
}
/**
* 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 int parse_nal_units(AVCodecParserContext *s, const uint8_t *buf,
int buf_size, AVCodecContext *avctx)
{
HEVCParserContext *ctx = s->priv_data;
HEVCParamSets *ps = &ctx->ps;
HEVCSEI *sei = &ctx->sei;
int ret, i;
/* set some sane default values */
s->pict_type = AV_PICTURE_TYPE_I;
s->key_frame = 0;
s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
ff_hevc_reset_sei(sei);
ret = ff_h2645_packet_split(&ctx->pkt, buf, buf_size, avctx, ctx->is_avc,
ctx->nal_length_size, AV_CODEC_ID_HEVC, 1, 0);
if (ret < 0)
return ret;
for (i = 0; i < ctx->pkt.nb_nals; i++) {
H2645NAL *nal = &ctx->pkt.nals[i];
GetBitContext *gb = &nal->gb;
if (nal->nuh_layer_id > 0)
continue;
switch (nal->type) {
case HEVC_NAL_VPS:
ff_hevc_decode_nal_vps(gb, avctx, ps);
break;
case HEVC_NAL_SPS:
ff_hevc_decode_nal_sps(gb, avctx, ps, 1);
break;
case HEVC_NAL_PPS:
ff_hevc_decode_nal_pps(gb, avctx, ps);
break;
case HEVC_NAL_SEI_PREFIX:
case HEVC_NAL_SEI_SUFFIX:
ff_hevc_decode_nal_sei(gb, avctx, sei, ps, nal->type);
break;
case HEVC_NAL_TRAIL_N:
case HEVC_NAL_TRAIL_R:
case HEVC_NAL_TSA_N:
case HEVC_NAL_TSA_R:
case HEVC_NAL_STSA_N:
case HEVC_NAL_STSA_R:
case HEVC_NAL_BLA_W_LP:
case HEVC_NAL_BLA_W_RADL:
case HEVC_NAL_BLA_N_LP:
case HEVC_NAL_IDR_W_RADL:
case HEVC_NAL_IDR_N_LP:
case HEVC_NAL_CRA_NUT:
case HEVC_NAL_RADL_N:
case HEVC_NAL_RADL_R:
case HEVC_NAL_RASL_N:
case HEVC_NAL_RASL_R:
if (ctx->sei.picture_timing.picture_struct == HEVC_SEI_PIC_STRUCT_FRAME_DOUBLING) {
s->repeat_pict = 1;
} else if (ctx->sei.picture_timing.picture_struct == HEVC_SEI_PIC_STRUCT_FRAME_TRIPLING) {
s->repeat_pict = 2;
}
ret = hevc_parse_slice_header(s, nal, avctx);
if (ret)
return ret;
break;
}
}
/* didn't find a picture! */
av_log(avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
return -1;
}
/**
* 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 >= HEVC_NAL_VPS && nut <= HEVC_NAL_EOB_NUT) || nut == HEVC_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 <= HEVC_NAL_RASL_R ||
(nut >= HEVC_NAL_BLA_W_LP && nut <= HEVC_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;
}
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;
int is_dummy_buf = !buf_size;
const uint8_t *dummy_buf = buf;
if (avctx->extradata && !ctx->parsed_extradata) {
ff_hevc_decode_extradata(avctx->extradata, avctx->extradata_size, &ctx->ps, &ctx->sei,
&ctx->is_avc, &ctx->nal_length_size, avctx->err_recognition,
1, 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;
}
}
is_dummy_buf &= (dummy_buf == buf);
if (!is_dummy_buf)
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)
{
const uint8_t *ptr = buf, *end = buf + buf_size;
uint32_t state = -1;
int has_vps = 0;
int has_sps = 0;
int has_pps = 0;
int nut;
while (ptr < end) {
ptr = avpriv_find_start_code(ptr, end, &state);
if ((state >> 8) != START_CODE)
break;
nut = (state >> 1) & 0x3F;
if (nut == HEVC_NAL_VPS)
has_vps = 1;
else if (nut == HEVC_NAL_SPS)
has_sps = 1;
else if (nut == HEVC_NAL_PPS)
has_pps = 1;
else if ((nut != HEVC_NAL_SEI_PREFIX || has_pps) &&
nut != HEVC_NAL_AUD) {
if (has_vps && has_sps) {
while (ptr - 4 > buf && ptr[-5] == 0)
ptr--;
return ptr - 4 - buf;
}
}
}
return 0;
}
static void hevc_parser_close(AVCodecParserContext *s)
{
HEVCParserContext *ctx = s->priv_data;
ff_hevc_ps_uninit(&ctx->ps);
ff_h2645_packet_uninit(&ctx->pkt);
ff_hevc_reset_sei(&ctx->sei);
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,
};
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