1/* 2 * H.26L/H.264/AVC/JVT/14496-10/... parser 3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> 4 * 5 * This file is part of Libav. 6 * 7 * Libav 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 * Libav 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 Libav; 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 parser. 25 * @author Michael Niedermayer <michaelni@gmx.at> 26 */ 27 28#include "parser.h" 29#include "h264data.h" 30#include "golomb.h" 31 32#include <assert.h> 33 34 35static int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size) 36{ 37 int i; 38 uint32_t state; 39 ParseContext *pc = &(h->s.parse_context); 40//printf("first %02X%02X%02X%02X\n", buf[0], buf[1],buf[2],buf[3]); 41// mb_addr= pc->mb_addr - 1; 42 state= pc->state; 43 if(state>13) 44 state= 7; 45 46 for(i=0; i<buf_size; i++){ 47 if(state==7){ 48#if HAVE_FAST_UNALIGNED 49 /* we check i<buf_size instead of i+3/7 because its simpler 50 * and there should be FF_INPUT_BUFFER_PADDING_SIZE bytes at the end 51 */ 52# if HAVE_FAST_64BIT 53 while(i<buf_size && !((~*(const uint64_t*)(buf+i) & (*(const uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL)) 54 i+=8; 55# else 56 while(i<buf_size && !((~*(const uint32_t*)(buf+i) & (*(const uint32_t*)(buf+i) - 0x01010101U)) & 0x80808080U)) 57 i+=4; 58# endif 59#endif 60 for(; i<buf_size; i++){ 61 if(!buf[i]){ 62 state=2; 63 break; 64 } 65 } 66 }else if(state<=2){ 67 if(buf[i]==1) state^= 5; //2->7, 1->4, 0->5 68 else if(buf[i]) state = 7; 69 else state>>=1; //2->1, 1->0, 0->0 70 }else if(state<=5){ 71 int v= buf[i] & 0x1F; 72 if(v==6 || v==7 || v==8 || v==9){ 73 if(pc->frame_start_found){ 74 i++; 75 goto found; 76 } 77 }else if(v==1 || v==2 || v==5){ 78 if(pc->frame_start_found){ 79 state+=8; 80 continue; 81 }else 82 pc->frame_start_found = 1; 83 } 84 state= 7; 85 }else{ 86 if(buf[i] & 0x80) 87 goto found; 88 state= 7; 89 } 90 } 91 pc->state= state; 92 return END_NOT_FOUND; 93 94found: 95 pc->state=7; 96 pc->frame_start_found= 0; 97 return i-(state&5); 98} 99 100/** 101 * Parse NAL units of found picture and decode some basic information. 102 * 103 * @param s parser context. 104 * @param avctx codec context. 105 * @param buf buffer with field/frame data. 106 * @param buf_size size of the buffer. 107 */ 108static inline int parse_nal_units(AVCodecParserContext *s, 109 AVCodecContext *avctx, 110 const uint8_t *buf, int buf_size) 111{ 112 H264Context *h = s->priv_data; 113 const uint8_t *buf_end = buf + buf_size; 114 unsigned int pps_id; 115 unsigned int slice_type; 116 int state = -1; 117 const uint8_t *ptr; 118 119 /* set some sane default values */ 120 s->pict_type = AV_PICTURE_TYPE_I; 121 s->key_frame = 0; 122 123 h->s.avctx= avctx; 124 h->sei_recovery_frame_cnt = -1; 125 h->sei_dpb_output_delay = 0; 126 h->sei_cpb_removal_delay = -1; 127 h->sei_buffering_period_present = 0; 128 129 if (!buf_size) 130 return 0; 131 132 for(;;) { 133 int src_length, dst_length, consumed; 134 buf = avpriv_mpv_find_start_code(buf, buf_end, &state); 135 if(buf >= buf_end) 136 break; 137 --buf; 138 src_length = buf_end - buf; 139 switch (state & 0x1f) { 140 case NAL_SLICE: 141 case NAL_IDR_SLICE: 142 // Do not walk the whole buffer just to decode slice header 143 if (src_length > 20) 144 src_length = 20; 145 break; 146 } 147 ptr= ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length); 148 if (ptr==NULL || dst_length < 0) 149 break; 150 151 init_get_bits(&h->s.gb, ptr, 8*dst_length); 152 switch(h->nal_unit_type) { 153 case NAL_SPS: 154 ff_h264_decode_seq_parameter_set(h); 155 break; 156 case NAL_PPS: 157 ff_h264_decode_picture_parameter_set(h, h->s.gb.size_in_bits); 158 break; 159 case NAL_SEI: 160 ff_h264_decode_sei(h); 161 break; 162 case NAL_IDR_SLICE: 163 s->key_frame = 1; 164 /* fall through */ 165 case NAL_SLICE: 166 get_ue_golomb(&h->s.gb); // skip first_mb_in_slice 167 slice_type = get_ue_golomb_31(&h->s.gb); 168 s->pict_type = golomb_to_pict_type[slice_type % 5]; 169 if (h->sei_recovery_frame_cnt >= 0) { 170 /* key frame, since recovery_frame_cnt is set */ 171 s->key_frame = 1; 172 } 173 pps_id= get_ue_golomb(&h->s.gb); 174 if(pps_id>=MAX_PPS_COUNT) { 175 av_log(h->s.avctx, AV_LOG_ERROR, "pps_id out of range\n"); 176 return -1; 177 } 178 if(!h->pps_buffers[pps_id]) { 179 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing PPS referenced\n"); 180 return -1; 181 } 182 h->pps= *h->pps_buffers[pps_id]; 183 if(!h->sps_buffers[h->pps.sps_id]) { 184 av_log(h->s.avctx, AV_LOG_ERROR, "non-existing SPS referenced\n"); 185 return -1; 186 } 187 h->sps = *h->sps_buffers[h->pps.sps_id]; 188 h->frame_num = get_bits(&h->s.gb, h->sps.log2_max_frame_num); 189 190 avctx->profile = ff_h264_get_profile(&h->sps); 191 avctx->level = h->sps.level_idc; 192 193 if(h->sps.frame_mbs_only_flag){ 194 h->s.picture_structure= PICT_FRAME; 195 }else{ 196 if(get_bits1(&h->s.gb)) { //field_pic_flag 197 h->s.picture_structure= PICT_TOP_FIELD + get_bits1(&h->s.gb); //bottom_field_flag 198 } else { 199 h->s.picture_structure= PICT_FRAME; 200 } 201 } 202 203 if(h->sps.pic_struct_present_flag) { 204 switch (h->sei_pic_struct) { 205 case SEI_PIC_STRUCT_TOP_FIELD: 206 case SEI_PIC_STRUCT_BOTTOM_FIELD: 207 s->repeat_pict = 0; 208 break; 209 case SEI_PIC_STRUCT_FRAME: 210 case SEI_PIC_STRUCT_TOP_BOTTOM: 211 case SEI_PIC_STRUCT_BOTTOM_TOP: 212 s->repeat_pict = 1; 213 break; 214 case SEI_PIC_STRUCT_TOP_BOTTOM_TOP: 215 case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM: 216 s->repeat_pict = 2; 217 break; 218 case SEI_PIC_STRUCT_FRAME_DOUBLING: 219 s->repeat_pict = 3; 220 break; 221 case SEI_PIC_STRUCT_FRAME_TRIPLING: 222 s->repeat_pict = 5; 223 break; 224 default: 225 s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0; 226 break; 227 } 228 } else { 229 s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0; 230 } 231 232 return 0; /* no need to evaluate the rest */ 233 } 234 buf += consumed; 235 } 236 /* didn't find a picture! */ 237 av_log(h->s.avctx, AV_LOG_ERROR, "missing picture in access unit\n"); 238 return -1; 239} 240 241static int h264_parse(AVCodecParserContext *s, 242 AVCodecContext *avctx, 243 const uint8_t **poutbuf, int *poutbuf_size, 244 const uint8_t *buf, int buf_size) 245{ 246 H264Context *h = s->priv_data; 247 ParseContext *pc = &h->s.parse_context; 248 int next; 249 250 if (!h->got_first) { 251 h->got_first = 1; 252 if (avctx->extradata_size) { 253 h->s.avctx = avctx; 254 // must be done like in the decoder. 255 // otherwise opening the parser, creating extradata, 256 // and then closing and opening again 257 // will cause has_b_frames to be always set. 258 // NB: estimate_timings_from_pts behaves exactly like this. 259 if (!avctx->has_b_frames) 260 h->s.low_delay = 1; 261 ff_h264_decode_extradata(h); 262 } 263 } 264 265 if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){ 266 next= buf_size; 267 }else{ 268 next= ff_h264_find_frame_end(h, buf, buf_size); 269 270 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { 271 *poutbuf = NULL; 272 *poutbuf_size = 0; 273 return buf_size; 274 } 275 276 if(next<0 && next != END_NOT_FOUND){ 277 assert(pc->last_index + next >= 0 ); 278 ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state 279 } 280 } 281 282 parse_nal_units(s, avctx, buf, buf_size); 283 284 if (h->sei_cpb_removal_delay >= 0) { 285 s->dts_sync_point = h->sei_buffering_period_present; 286 s->dts_ref_dts_delta = h->sei_cpb_removal_delay; 287 s->pts_dts_delta = h->sei_dpb_output_delay; 288 } else { 289 s->dts_sync_point = INT_MIN; 290 s->dts_ref_dts_delta = INT_MIN; 291 s->pts_dts_delta = INT_MIN; 292 } 293 294 if (s->flags & PARSER_FLAG_ONCE) { 295 s->flags &= PARSER_FLAG_COMPLETE_FRAMES; 296 } 297 298 *poutbuf = buf; 299 *poutbuf_size = buf_size; 300 return next; 301} 302 303static int h264_split(AVCodecContext *avctx, 304 const uint8_t *buf, int buf_size) 305{ 306 int i; 307 uint32_t state = -1; 308 int has_sps= 0; 309 310 for(i=0; i<=buf_size; i++){ 311 if((state&0xFFFFFF1F) == 0x107) 312 has_sps=1; 313/* if((state&0xFFFFFF1F) == 0x101 || (state&0xFFFFFF1F) == 0x102 || (state&0xFFFFFF1F) == 0x105){ 314 }*/ 315 if((state&0xFFFFFF00) == 0x100 && (state&0xFFFFFF1F) != 0x107 && (state&0xFFFFFF1F) != 0x108 && (state&0xFFFFFF1F) != 0x109){ 316 if(has_sps){ 317 while(i>4 && buf[i-5]==0) i--; 318 return i-4; 319 } 320 } 321 if (i<buf_size) 322 state= (state<<8) | buf[i]; 323 } 324 return 0; 325} 326 327static void close(AVCodecParserContext *s) 328{ 329 H264Context *h = s->priv_data; 330 ParseContext *pc = &h->s.parse_context; 331 332 av_free(pc->buffer); 333 ff_h264_free_context(h); 334} 335 336static int init(AVCodecParserContext *s) 337{ 338 H264Context *h = s->priv_data; 339 h->thread_context[0] = h; 340 h->s.slice_context_count = 1; 341 return 0; 342} 343 344AVCodecParser ff_h264_parser = { 345 .codec_ids = { CODEC_ID_H264 }, 346 .priv_data_size = sizeof(H264Context), 347 .parser_init = init, 348 .parser_parse = h264_parse, 349 .parser_close = close, 350 .split = h264_split, 351}; 352