Libav
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00001 /* 00002 * H.26L/H.264/AVC/JVT/14496-10/... sei decoding 00003 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> 00004 * 00005 * This file is part of FFmpeg. 00006 * 00007 * FFmpeg is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * FFmpeg is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with FFmpeg; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00028 #include "internal.h" 00029 #include "avcodec.h" 00030 #include "h264.h" 00031 #include "golomb.h" 00032 00033 //#undef NDEBUG 00034 #include <assert.h> 00035 00036 static const uint8_t sei_num_clock_ts_table[9]={ 00037 1, 1, 1, 2, 2, 3, 3, 2, 3 00038 }; 00039 00040 void ff_h264_reset_sei(H264Context *h) { 00041 h->sei_recovery_frame_cnt = -1; 00042 h->sei_dpb_output_delay = 0; 00043 h->sei_cpb_removal_delay = -1; 00044 h->sei_buffering_period_present = 0; 00045 } 00046 00047 static int decode_picture_timing(H264Context *h){ 00048 MpegEncContext * const s = &h->s; 00049 if(h->sps.nal_hrd_parameters_present_flag || h->sps.vcl_hrd_parameters_present_flag){ 00050 h->sei_cpb_removal_delay = get_bits(&s->gb, h->sps.cpb_removal_delay_length); 00051 h->sei_dpb_output_delay = get_bits(&s->gb, h->sps.dpb_output_delay_length); 00052 } 00053 if(h->sps.pic_struct_present_flag){ 00054 unsigned int i, num_clock_ts; 00055 h->sei_pic_struct = get_bits(&s->gb, 4); 00056 h->sei_ct_type = 0; 00057 00058 if (h->sei_pic_struct > SEI_PIC_STRUCT_FRAME_TRIPLING) 00059 return -1; 00060 00061 num_clock_ts = sei_num_clock_ts_table[h->sei_pic_struct]; 00062 00063 for (i = 0 ; i < num_clock_ts ; i++){ 00064 if(get_bits(&s->gb, 1)){ /* clock_timestamp_flag */ 00065 unsigned int full_timestamp_flag; 00066 h->sei_ct_type |= 1<<get_bits(&s->gb, 2); 00067 skip_bits(&s->gb, 1); /* nuit_field_based_flag */ 00068 skip_bits(&s->gb, 5); /* counting_type */ 00069 full_timestamp_flag = get_bits(&s->gb, 1); 00070 skip_bits(&s->gb, 1); /* discontinuity_flag */ 00071 skip_bits(&s->gb, 1); /* cnt_dropped_flag */ 00072 skip_bits(&s->gb, 8); /* n_frames */ 00073 if(full_timestamp_flag){ 00074 skip_bits(&s->gb, 6); /* seconds_value 0..59 */ 00075 skip_bits(&s->gb, 6); /* minutes_value 0..59 */ 00076 skip_bits(&s->gb, 5); /* hours_value 0..23 */ 00077 }else{ 00078 if(get_bits(&s->gb, 1)){ /* seconds_flag */ 00079 skip_bits(&s->gb, 6); /* seconds_value range 0..59 */ 00080 if(get_bits(&s->gb, 1)){ /* minutes_flag */ 00081 skip_bits(&s->gb, 6); /* minutes_value 0..59 */ 00082 if(get_bits(&s->gb, 1)) /* hours_flag */ 00083 skip_bits(&s->gb, 5); /* hours_value 0..23 */ 00084 } 00085 } 00086 } 00087 if(h->sps.time_offset_length > 0) 00088 skip_bits(&s->gb, h->sps.time_offset_length); /* time_offset */ 00089 } 00090 } 00091 00092 if(s->avctx->debug & FF_DEBUG_PICT_INFO) 00093 av_log(s->avctx, AV_LOG_DEBUG, "ct_type:%X pic_struct:%d\n", h->sei_ct_type, h->sei_pic_struct); 00094 } 00095 return 0; 00096 } 00097 00098 static int decode_unregistered_user_data(H264Context *h, int size){ 00099 MpegEncContext * const s = &h->s; 00100 uint8_t user_data[16+256]; 00101 int e, build, i; 00102 00103 if(size<16) 00104 return -1; 00105 00106 for(i=0; i<sizeof(user_data)-1 && i<size; i++){ 00107 user_data[i]= get_bits(&s->gb, 8); 00108 } 00109 00110 user_data[i]= 0; 00111 e= sscanf(user_data+16, "x264 - core %d"/*%s - H.264/MPEG-4 AVC codec - Copyleft 2005 - http://www.videolan.org/x264.html*/, &build); 00112 if(e==1 && build>0) 00113 h->x264_build= build; 00114 00115 if(s->avctx->debug & FF_DEBUG_BUGS) 00116 av_log(s->avctx, AV_LOG_DEBUG, "user data:\"%s\"\n", user_data+16); 00117 00118 for(; i<size; i++) 00119 skip_bits(&s->gb, 8); 00120 00121 return 0; 00122 } 00123 00124 static int decode_recovery_point(H264Context *h){ 00125 MpegEncContext * const s = &h->s; 00126 00127 h->sei_recovery_frame_cnt = get_ue_golomb(&s->gb); 00128 skip_bits(&s->gb, 4); /* 1b exact_match_flag, 1b broken_link_flag, 2b changing_slice_group_idc */ 00129 00130 return 0; 00131 } 00132 00133 static int decode_buffering_period(H264Context *h){ 00134 MpegEncContext * const s = &h->s; 00135 unsigned int sps_id; 00136 int sched_sel_idx; 00137 SPS *sps; 00138 00139 sps_id = get_ue_golomb_31(&s->gb); 00140 if(sps_id > 31 || !h->sps_buffers[sps_id]) { 00141 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing SPS %d referenced in buffering period\n", sps_id); 00142 return -1; 00143 } 00144 sps = h->sps_buffers[sps_id]; 00145 00146 // NOTE: This is really so duplicated in the standard... See H.264, D.1.1 00147 if (sps->nal_hrd_parameters_present_flag) { 00148 for (sched_sel_idx = 0; sched_sel_idx < sps->cpb_cnt; sched_sel_idx++) { 00149 h->initial_cpb_removal_delay[sched_sel_idx] = get_bits(&s->gb, sps->initial_cpb_removal_delay_length); 00150 skip_bits(&s->gb, sps->initial_cpb_removal_delay_length); // initial_cpb_removal_delay_offset 00151 } 00152 } 00153 if (sps->vcl_hrd_parameters_present_flag) { 00154 for (sched_sel_idx = 0; sched_sel_idx < sps->cpb_cnt; sched_sel_idx++) { 00155 h->initial_cpb_removal_delay[sched_sel_idx] = get_bits(&s->gb, sps->initial_cpb_removal_delay_length); 00156 skip_bits(&s->gb, sps->initial_cpb_removal_delay_length); // initial_cpb_removal_delay_offset 00157 } 00158 } 00159 00160 h->sei_buffering_period_present = 1; 00161 return 0; 00162 } 00163 00164 int ff_h264_decode_sei(H264Context *h){ 00165 MpegEncContext * const s = &h->s; 00166 00167 while(get_bits_count(&s->gb) + 16 < s->gb.size_in_bits){ 00168 int size, type; 00169 00170 type=0; 00171 do{ 00172 type+= show_bits(&s->gb, 8); 00173 }while(get_bits(&s->gb, 8) == 255); 00174 00175 size=0; 00176 do{ 00177 size+= show_bits(&s->gb, 8); 00178 }while(get_bits(&s->gb, 8) == 255); 00179 00180 switch(type){ 00181 case SEI_TYPE_PIC_TIMING: // Picture timing SEI 00182 if(decode_picture_timing(h) < 0) 00183 return -1; 00184 break; 00185 case SEI_TYPE_USER_DATA_UNREGISTERED: 00186 if(decode_unregistered_user_data(h, size) < 0) 00187 return -1; 00188 break; 00189 case SEI_TYPE_RECOVERY_POINT: 00190 if(decode_recovery_point(h) < 0) 00191 return -1; 00192 break; 00193 case SEI_BUFFERING_PERIOD: 00194 if(decode_buffering_period(h) < 0) 00195 return -1; 00196 break; 00197 default: 00198 skip_bits(&s->gb, 8*size); 00199 } 00200 00201 //FIXME check bits here 00202 align_get_bits(&s->gb); 00203 } 00204 00205 return 0; 00206 }