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ffmpeg/libavcodec/h264_sei.c

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/*
* H.26L/H.264/AVC/JVT/14496-10/... sei decoding
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
*
* 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
*/
/**
* @file
* H.264 / AVC / MPEG4 part10 sei decoding.
* @author Michael Niedermayer <michaelni@gmx.at>
*/
#include "internal.h"
#include "avcodec.h"
#include "h264.h"
#include "golomb.h"
#include <assert.h>
static const uint8_t sei_num_clock_ts_table[9] = {
1, 1, 1, 2, 2, 3, 3, 2, 3
};
void ff_h264_reset_sei(H264Context *h)
{
h->sei_recovery_frame_cnt = -1;
h->sei_dpb_output_delay = 0;
h->sei_cpb_removal_delay = -1;
h->sei_buffering_period_present = 0;
}
static int decode_picture_timing(H264Context *h)
{
if (h->sps.nal_hrd_parameters_present_flag ||
h->sps.vcl_hrd_parameters_present_flag) {
h->sei_cpb_removal_delay = get_bits(&h->gb,
h->sps.cpb_removal_delay_length);
h->sei_dpb_output_delay = get_bits(&h->gb,
h->sps.dpb_output_delay_length);
}
if (h->sps.pic_struct_present_flag) {
unsigned int i, num_clock_ts;
h->sei_pic_struct = get_bits(&h->gb, 4);
h->sei_ct_type = 0;
if (h->sei_pic_struct > SEI_PIC_STRUCT_FRAME_TRIPLING)
return AVERROR_INVALIDDATA;
num_clock_ts = sei_num_clock_ts_table[h->sei_pic_struct];
for (i = 0; i < num_clock_ts; i++) {
if (get_bits(&h->gb, 1)) { /* clock_timestamp_flag */
unsigned int full_timestamp_flag;
h->sei_ct_type |= 1 << get_bits(&h->gb, 2);
skip_bits(&h->gb, 1); /* nuit_field_based_flag */
skip_bits(&h->gb, 5); /* counting_type */
full_timestamp_flag = get_bits(&h->gb, 1);
skip_bits(&h->gb, 1); /* discontinuity_flag */
skip_bits(&h->gb, 1); /* cnt_dropped_flag */
skip_bits(&h->gb, 8); /* n_frames */
if (full_timestamp_flag) {
skip_bits(&h->gb, 6); /* seconds_value 0..59 */
skip_bits(&h->gb, 6); /* minutes_value 0..59 */
skip_bits(&h->gb, 5); /* hours_value 0..23 */
} else {
if (get_bits(&h->gb, 1)) { /* seconds_flag */
skip_bits(&h->gb, 6); /* seconds_value range 0..59 */
if (get_bits(&h->gb, 1)) { /* minutes_flag */
skip_bits(&h->gb, 6); /* minutes_value 0..59 */
if (get_bits(&h->gb, 1)) /* hours_flag */
skip_bits(&h->gb, 5); /* hours_value 0..23 */
}
}
}
if (h->sps.time_offset_length > 0)
skip_bits(&h->gb,
h->sps.time_offset_length); /* time_offset */
}
}
if (h->avctx->debug & FF_DEBUG_PICT_INFO)
av_log(h->avctx, AV_LOG_DEBUG, "ct_type:%X pic_struct:%d\n",
h->sei_ct_type, h->sei_pic_struct);
}
return 0;
}
static int decode_unregistered_user_data(H264Context *h, int size)
{
uint8_t user_data[16 + 256];
int e, build, i;
if (size < 16)
return AVERROR_INVALIDDATA;
for (i = 0; i < sizeof(user_data) - 1 && i < size; i++)
user_data[i] = get_bits(&h->gb, 8);
user_data[i] = 0;
e = sscanf(user_data + 16, "x264 - core %d", &build);
if (e == 1 && build > 0)
h->x264_build = build;
if (h->avctx->debug & FF_DEBUG_BUGS)
av_log(h->avctx, AV_LOG_DEBUG, "user data:\"%s\"\n", user_data + 16);
for (; i < size; i++)
skip_bits(&h->gb, 8);
return 0;
}
static int decode_recovery_point(H264Context *h)
{
h->sei_recovery_frame_cnt = get_ue_golomb(&h->gb);
/* 1b exact_match_flag,
* 1b broken_link_flag,
* 2b changing_slice_group_idc */
skip_bits(&h->gb, 4);
return 0;
}
static int decode_buffering_period(H264Context *h)
{
unsigned int sps_id;
int sched_sel_idx;
SPS *sps;
sps_id = get_ue_golomb_31(&h->gb);
if (sps_id > 31 || !h->sps_buffers[sps_id]) {
av_log(h->avctx, AV_LOG_ERROR,
"non-existing SPS %d referenced in buffering period\n", sps_id);
return AVERROR_INVALIDDATA;
}
sps = h->sps_buffers[sps_id];
// NOTE: This is really so duplicated in the standard... See H.264, D.1.1
if (sps->nal_hrd_parameters_present_flag) {
for (sched_sel_idx = 0; sched_sel_idx < sps->cpb_cnt; sched_sel_idx++) {
h->initial_cpb_removal_delay[sched_sel_idx] =
get_bits(&h->gb, sps->initial_cpb_removal_delay_length);
// initial_cpb_removal_delay_offset
skip_bits(&h->gb, sps->initial_cpb_removal_delay_length);
}
}
if (sps->vcl_hrd_parameters_present_flag) {
for (sched_sel_idx = 0; sched_sel_idx < sps->cpb_cnt; sched_sel_idx++) {
h->initial_cpb_removal_delay[sched_sel_idx] =
get_bits(&h->gb, sps->initial_cpb_removal_delay_length);
// initial_cpb_removal_delay_offset
skip_bits(&h->gb, sps->initial_cpb_removal_delay_length);
}
}
h->sei_buffering_period_present = 1;
return 0;
}
int ff_h264_decode_sei(H264Context *h)
{
while (get_bits_left(&h->gb) > 16) {
int size = 0;
int type = 0;
int ret = 0;
do
type += show_bits(&h->gb, 8);
while (get_bits(&h->gb, 8) == 255);
do
size += show_bits(&h->gb, 8);
while (get_bits(&h->gb, 8) == 255);
if (size > get_bits_left(&h->gb) / 8) {
av_log(h->avctx, AV_LOG_ERROR, "SEI type %d truncated at %d\n",
type, get_bits_left(&h->gb));
return AVERROR_INVALIDDATA;
}
switch (type) {
case SEI_TYPE_PIC_TIMING: // Picture timing SEI
ret = decode_picture_timing(h);
if (ret < 0)
return ret;
break;
case SEI_TYPE_USER_DATA_UNREGISTERED:
ret = decode_unregistered_user_data(h, size);
if (ret < 0)
return ret;
break;
case SEI_TYPE_RECOVERY_POINT:
ret = decode_recovery_point(h);
if (ret < 0)
return ret;
break;
case SEI_BUFFERING_PERIOD:
ret = decode_buffering_period(h);
if (ret < 0)
return ret;
break;
default:
av_log(h->avctx, AV_LOG_DEBUG, "unknown SEI type %d\n", type);
skip_bits(&h->gb, 8 * size);
}
// FIXME check bits here
align_get_bits(&h->gb);
}
return 0;
}
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