git.sesse.net Git - ffmpeg/blob - libavcodec/h264_sei.c

   1 /*
   2  * H.26L/H.264/AVC/JVT/14496-10/... sei decoding
   3  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * H.264 / AVC / MPEG4 part10 sei decoding.
  25  * @author Michael Niedermayer <michaelni@gmx.at>
  26  */
  27
  28 #include "internal.h"
  29 #include "avcodec.h"
  30 #include "h264.h"
  31 #include "golomb.h"
  32
  33 //#undef NDEBUG
  34 #include <assert.h>
  35
  36 static const uint8_t sei_num_clock_ts_table[9]={
  37     1,  1,  1,  2,  2,  3,  3,  2,  3
  38 };
  39
  40 void ff_h264_reset_sei(H264Context *h) {
  41     h->sei_recovery_frame_cnt       = -1;
  42     h->sei_dpb_output_delay         =  0;
  43     h->sei_cpb_removal_delay        = -1;
  44     h->sei_buffering_period_present =  0;
  45 }
  46
  47 static int decode_picture_timing(H264Context *h){
  48     SPS *sps = &h->sps;
  49     int i;
  50
  51     for (i = 0; i<MAX_SPS_COUNT; i++)
  52         if (!sps->log2_max_frame_num && h->sps_buffers[i])
  53             sps = h->sps_buffers[i];
  54
  55     if(sps->nal_hrd_parameters_present_flag || sps->vcl_hrd_parameters_present_flag){
  56         h->sei_cpb_removal_delay = get_bits_long(&h->gb, sps->cpb_removal_delay_length);
  57         h->sei_dpb_output_delay = get_bits_long(&h->gb, sps->dpb_output_delay_length);
  58     }
  59     if(sps->pic_struct_present_flag){
  60         unsigned int i, num_clock_ts;
  61         h->sei_pic_struct = get_bits(&h->gb, 4);
  62         h->sei_ct_type    = 0;
  63
  64         if (h->sei_pic_struct > SEI_PIC_STRUCT_FRAME_TRIPLING)
  65             return -1;
  66
  67         num_clock_ts = sei_num_clock_ts_table[h->sei_pic_struct];
  68
  69         for (i = 0 ; i < num_clock_ts ; i++){
  70             if(get_bits(&h->gb, 1)){                  /* clock_timestamp_flag */
  71                 unsigned int full_timestamp_flag;
  72                 h->sei_ct_type |= 1<<get_bits(&h->gb, 2);
  73                 skip_bits(&h->gb, 1);                 /* nuit_field_based_flag */
  74                 skip_bits(&h->gb, 5);                 /* counting_type */
  75                 full_timestamp_flag = get_bits(&h->gb, 1);
  76                 skip_bits(&h->gb, 1);                 /* discontinuity_flag */
  77                 skip_bits(&h->gb, 1);                 /* cnt_dropped_flag */
  78                 skip_bits(&h->gb, 8);                 /* n_frames */
  79                 if(full_timestamp_flag){
  80                     skip_bits(&h->gb, 6);             /* seconds_value 0..59 */
  81                     skip_bits(&h->gb, 6);             /* minutes_value 0..59 */
  82                     skip_bits(&h->gb, 5);             /* hours_value 0..23 */
  83                 }else{
  84                     if(get_bits(&h->gb, 1)){          /* seconds_flag */
  85                         skip_bits(&h->gb, 6);         /* seconds_value range 0..59 */
  86                         if(get_bits(&h->gb, 1)){      /* minutes_flag */
  87                             skip_bits(&h->gb, 6);     /* minutes_value 0..59 */
  88                             if(get_bits(&h->gb, 1))   /* hours_flag */
  89                                 skip_bits(&h->gb, 5); /* hours_value 0..23 */
  90                         }
  91                     }
  92                 }
  93                 if(sps->time_offset_length > 0)
  94                     skip_bits(&h->gb, sps->time_offset_length); /* time_offset */
  95             }
  96         }
  97
  98         if(h->avctx->debug & FF_DEBUG_PICT_INFO)
  99             av_log(h->avctx, AV_LOG_DEBUG, "ct_type:%X pic_struct:%d\n", h->sei_ct_type, h->sei_pic_struct);
 100     }
 101     return 0;
 102 }
 103
 104 static int decode_user_data_itu_t_t35(H264Context *h, int size) {
 105     uint32_t user_identifier;
 106     int dtg_active_format;
 107
 108     if (size < 7)
 109         return -1;
 110     size -= 7;
 111
 112     skip_bits(&h->gb, 8);   // country_code
 113     skip_bits(&h->gb, 16);  // provider_code
 114     user_identifier = get_bits_long(&h->gb, 32);
 115
 116     switch (user_identifier) {
 117         case 0x44544731:    // "DTG1" - AFD_data
 118             if (size < 1)
 119                 return -1;
 120             skip_bits(&h->gb, 1);
 121             if (get_bits(&h->gb, 1)) {
 122                 skip_bits(&h->gb, 6);
 123                 if (size < 2)
 124                     return -1;
 125                 skip_bits(&h->gb, 4);
 126                 dtg_active_format = get_bits(&h->gb, 4);
 127                 h->avctx->dtg_active_format = dtg_active_format;
 128             } else {
 129                 skip_bits(&h->gb, 6);
 130             }
 131             break;
 132         default:
 133             skip_bits(&h->gb, size * 8);
 134             break;
 135     }
 136
 137     return 0;
 138 }
 139
 140 static int decode_unregistered_user_data(H264Context *h, int size){
 141     uint8_t user_data[16+256];
 142     int e, build, i;
 143
 144     if(size<16)
 145         return -1;
 146
 147     for(i=0; i<sizeof(user_data)-1 && i<size; i++){
 148         user_data[i]= get_bits(&h->gb, 8);
 149     }
 150
 151     user_data[i]= 0;
 152     e= sscanf(user_data+16, "x264 - core %d"/*%s - H.264/MPEG-4 AVC codec - Copyleft 2005 - http://www.videolan.org/x264.html*/, &build);
 153     if(e==1 && build>0)
 154         h->x264_build= build;
 155     if(e==1 && build==1 && !strncmp(user_data+16, "x264 - core 0000", 16))
 156         h->x264_build = 67;
 157
 158     if(h->avctx->debug & FF_DEBUG_BUGS)
 159         av_log(h->avctx, AV_LOG_DEBUG, "user data:\"%s\"\n", user_data+16);
 160
 161     for(; i<size; i++)
 162         skip_bits(&h->gb, 8);
 163
 164     return 0;
 165 }
 166
 167 static int decode_recovery_point(H264Context *h){
 168     h->sei_recovery_frame_cnt = get_ue_golomb(&h->gb);
 169     skip_bits(&h->gb, 4);       /* 1b exact_match_flag, 1b broken_link_flag, 2b changing_slice_group_idc */
 170
 171     if(h->avctx->debug & FF_DEBUG_PICT_INFO)
 172         av_log(h->avctx, AV_LOG_DEBUG, "sei_recovery_frame_cnt: %d\n", h->sei_recovery_frame_cnt);
 173
 174     return 0;
 175 }
 176
 177 static int decode_buffering_period(H264Context *h){
 178     unsigned int sps_id;
 179     int sched_sel_idx;
 180     SPS *sps;
 181
 182     sps_id = get_ue_golomb_31(&h->gb);
 183     if(sps_id > 31 || !h->sps_buffers[sps_id]) {
 184         av_log(h->avctx, AV_LOG_ERROR, "non-existing SPS %d referenced in buffering period\n", sps_id);
 185         return -1;
 186     }
 187     sps = h->sps_buffers[sps_id];
 188
 189     // NOTE: This is really so duplicated in the standard... See H.264, D.1.1
 190     if (sps->nal_hrd_parameters_present_flag) {
 191         for (sched_sel_idx = 0; sched_sel_idx < sps->cpb_cnt; sched_sel_idx++) {
 192             h->initial_cpb_removal_delay[sched_sel_idx] = get_bits_long(&h->gb, sps->initial_cpb_removal_delay_length);
 193             skip_bits(&h->gb, sps->initial_cpb_removal_delay_length); // initial_cpb_removal_delay_offset
 194         }
 195     }
 196     if (sps->vcl_hrd_parameters_present_flag) {
 197         for (sched_sel_idx = 0; sched_sel_idx < sps->cpb_cnt; sched_sel_idx++) {
 198             h->initial_cpb_removal_delay[sched_sel_idx] = get_bits_long(&h->gb, sps->initial_cpb_removal_delay_length);
 199             skip_bits(&h->gb, sps->initial_cpb_removal_delay_length); // initial_cpb_removal_delay_offset
 200         }
 201     }
 202
 203     h->sei_buffering_period_present = 1;
 204     return 0;
 205 }
 206
 207 int ff_h264_decode_sei(H264Context *h){
 208     while (get_bits_left(&h->gb) > 16) {
 209         int size, type;
 210
 211         type=0;
 212         do{
 213             if (get_bits_left(&h->gb) < 8)
 214                 return -1;
 215             type+= show_bits(&h->gb, 8);
 216         }while(get_bits(&h->gb, 8) == 255);
 217
 218         size=0;
 219         do{
 220             if (get_bits_left(&h->gb) < 8)
 221                 return -1;
 222             size+= show_bits(&h->gb, 8);
 223         }while(get_bits(&h->gb, 8) == 255);
 224
 225         if(h->avctx->debug&FF_DEBUG_STARTCODE)
 226             av_log(h->avctx, AV_LOG_DEBUG, "SEI %d len:%d\n", type, size);
 227
 228         switch(type){
 229         case SEI_TYPE_PIC_TIMING: // Picture timing SEI
 230             if(decode_picture_timing(h) < 0)
 231                 return -1;
 232             break;
 233         case SEI_TYPE_USER_DATA_ITU_T_T35:
 234             if(decode_user_data_itu_t_t35(h, size) < 0)
 235                 return -1;
 236             break;
 237         case SEI_TYPE_USER_DATA_UNREGISTERED:
 238             if(decode_unregistered_user_data(h, size) < 0)
 239                 return -1;
 240             break;
 241         case SEI_TYPE_RECOVERY_POINT:
 242             if(decode_recovery_point(h) < 0)
 243                 return -1;
 244             break;
 245         case SEI_BUFFERING_PERIOD:
 246             if(decode_buffering_period(h) < 0)
 247                 return -1;
 248             break;
 249         default:
 250             skip_bits(&h->gb, 8*size);
 251         }
 252
 253         //FIXME check bits here
 254         align_get_bits(&h->gb);
 255     }
 256
 257     return 0;
 258 }