1/* 2 * Chinese AVS video (AVS1-P2, JiZhun profile) decoder. 3 * Copyright (c) 2006 Stefan Gehrer <stefan.gehrer@gmx.de> 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 * Chinese AVS video (AVS1-P2, JiZhun profile) decoder 25 * @author Stefan Gehrer <stefan.gehrer@gmx.de> 26 */ 27 28#include "avcodec.h" 29#include "get_bits.h" 30#include "golomb.h" 31#include "cavs.h" 32 33static const uint8_t mv_scan[4] = { 34 MV_FWD_X0,MV_FWD_X1, 35 MV_FWD_X2,MV_FWD_X3 36}; 37 38static const uint8_t cbp_tab[64][2] = { 39 {63, 0},{15,15},{31,63},{47,31},{ 0,16},{14,32},{13,47},{11,13}, 40 { 7,14},{ 5,11},{10,12},{ 8, 5},{12,10},{61, 7},{ 4,48},{55, 3}, 41 { 1, 2},{ 2, 8},{59, 4},{ 3, 1},{62,61},{ 9,55},{ 6,59},{29,62}, 42 {45,29},{51,27},{23,23},{39,19},{27,30},{46,28},{53, 9},{30, 6}, 43 {43,60},{37,21},{60,44},{16,26},{21,51},{28,35},{19,18},{35,20}, 44 {42,24},{26,53},{44,17},{32,37},{58,39},{24,45},{20,58},{17,43}, 45 {18,42},{48,46},{22,36},{33,33},{25,34},{49,40},{40,52},{36,49}, 46 {34,50},{50,56},{52,25},{54,22},{41,54},{56,57},{38,41},{57,38} 47}; 48 49/***************************************************************************** 50 * 51 * motion vector prediction 52 * 53 ****************************************************************************/ 54 55static inline void store_mvs(AVSContext *h) { 56 h->col_mv[h->mbidx*4 + 0] = h->mv[MV_FWD_X0]; 57 h->col_mv[h->mbidx*4 + 1] = h->mv[MV_FWD_X1]; 58 h->col_mv[h->mbidx*4 + 2] = h->mv[MV_FWD_X2]; 59 h->col_mv[h->mbidx*4 + 3] = h->mv[MV_FWD_X3]; 60} 61 62static inline void mv_pred_direct(AVSContext *h, cavs_vector *pmv_fw, 63 cavs_vector *col_mv) { 64 cavs_vector *pmv_bw = pmv_fw + MV_BWD_OFFS; 65 int den = h->direct_den[col_mv->ref]; 66 int m = col_mv->x >> 31; 67 68 pmv_fw->dist = h->dist[1]; 69 pmv_bw->dist = h->dist[0]; 70 pmv_fw->ref = 1; 71 pmv_bw->ref = 0; 72 /* scale the co-located motion vector according to its temporal span */ 73 pmv_fw->x = (((den+(den*col_mv->x*pmv_fw->dist^m)-m-1)>>14)^m)-m; 74 pmv_bw->x = m-(((den+(den*col_mv->x*pmv_bw->dist^m)-m-1)>>14)^m); 75 m = col_mv->y >> 31; 76 pmv_fw->y = (((den+(den*col_mv->y*pmv_fw->dist^m)-m-1)>>14)^m)-m; 77 pmv_bw->y = m-(((den+(den*col_mv->y*pmv_bw->dist^m)-m-1)>>14)^m); 78} 79 80static inline void mv_pred_sym(AVSContext *h, cavs_vector *src, enum cavs_block size) { 81 cavs_vector *dst = src + MV_BWD_OFFS; 82 83 /* backward mv is the scaled and negated forward mv */ 84 dst->x = -((src->x * h->sym_factor + 256) >> 9); 85 dst->y = -((src->y * h->sym_factor + 256) >> 9); 86 dst->ref = 0; 87 dst->dist = h->dist[0]; 88 set_mvs(dst, size); 89} 90 91/***************************************************************************** 92 * 93 * residual data decoding 94 * 95 ****************************************************************************/ 96 97/** kth-order exponential golomb code */ 98static inline int get_ue_code(GetBitContext *gb, int order) { 99 if(order) { 100 int ret = get_ue_golomb(gb) << order; 101 return ret + get_bits(gb,order); 102 } 103 return get_ue_golomb(gb); 104} 105 106/** 107 * decode coefficients from one 8x8 block, dequantize, inverse transform 108 * and add them to sample block 109 * @param r pointer to 2D VLC table 110 * @param esc_golomb_order escape codes are k-golomb with this order k 111 * @param qp quantizer 112 * @param dst location of sample block 113 * @param stride line stride in frame buffer 114 */ 115static int decode_residual_block(AVSContext *h, GetBitContext *gb, 116 const struct dec_2dvlc *r, int esc_golomb_order, 117 int qp, uint8_t *dst, int stride) { 118 int i, level_code, esc_code, level, run, mask; 119 DCTELEM level_buf[65]; 120 uint8_t run_buf[65]; 121 DCTELEM *block = h->block; 122 123 for(i=0;i<65;i++) { 124 level_code = get_ue_code(gb,r->golomb_order); 125 if(level_code >= ESCAPE_CODE) { 126 run = ((level_code - ESCAPE_CODE) >> 1) + 1; 127 esc_code = get_ue_code(gb,esc_golomb_order); 128 level = esc_code + (run > r->max_run ? 1 : r->level_add[run]); 129 while(level > r->inc_limit) 130 r++; 131 mask = -(level_code & 1); 132 level = (level^mask) - mask; 133 } else { 134 level = r->rltab[level_code][0]; 135 if(!level) //end of block signal 136 break; 137 run = r->rltab[level_code][1]; 138 r += r->rltab[level_code][2]; 139 } 140 level_buf[i] = level; 141 run_buf[i] = run; 142 } 143 if(dequant(h,level_buf, run_buf, block, ff_cavs_dequant_mul[qp], 144 ff_cavs_dequant_shift[qp], i)) 145 return -1; 146 h->s.dsp.cavs_idct8_add(dst,block,stride); 147 h->s.dsp.clear_block(block); 148 return 0; 149} 150 151 152static inline void decode_residual_chroma(AVSContext *h) { 153 if(h->cbp & (1<<4)) 154 decode_residual_block(h,&h->s.gb,ff_cavs_chroma_dec,0, 155 ff_cavs_chroma_qp[h->qp],h->cu,h->c_stride); 156 if(h->cbp & (1<<5)) 157 decode_residual_block(h,&h->s.gb,ff_cavs_chroma_dec,0, 158 ff_cavs_chroma_qp[h->qp],h->cv,h->c_stride); 159} 160 161static inline int decode_residual_inter(AVSContext *h) { 162 int block; 163 164 /* get coded block pattern */ 165 int cbp= get_ue_golomb(&h->s.gb); 166 if(cbp > 63){ 167 av_log(h->s.avctx, AV_LOG_ERROR, "illegal inter cbp\n"); 168 return -1; 169 } 170 h->cbp = cbp_tab[cbp][1]; 171 172 /* get quantizer */ 173 if(h->cbp && !h->qp_fixed) 174 h->qp = (h->qp + get_se_golomb(&h->s.gb)) & 63; 175 for(block=0;block<4;block++) 176 if(h->cbp & (1<<block)) 177 decode_residual_block(h,&h->s.gb,ff_cavs_inter_dec,0,h->qp, 178 h->cy + h->luma_scan[block], h->l_stride); 179 decode_residual_chroma(h); 180 181 return 0; 182} 183 184/***************************************************************************** 185 * 186 * macroblock level 187 * 188 ****************************************************************************/ 189 190static int decode_mb_i(AVSContext *h, int cbp_code) { 191 GetBitContext *gb = &h->s.gb; 192 int block, pred_mode_uv; 193 uint8_t top[18]; 194 uint8_t *left = NULL; 195 uint8_t *d; 196 197 ff_cavs_init_mb(h); 198 199 /* get intra prediction modes from stream */ 200 for(block=0;block<4;block++) { 201 int nA,nB,predpred; 202 int pos = ff_cavs_scan3x3[block]; 203 204 nA = h->pred_mode_Y[pos-1]; 205 nB = h->pred_mode_Y[pos-3]; 206 predpred = FFMIN(nA,nB); 207 if(predpred == NOT_AVAIL) // if either is not available 208 predpred = INTRA_L_LP; 209 if(!get_bits1(gb)){ 210 int rem_mode= get_bits(gb, 2); 211 predpred = rem_mode + (rem_mode >= predpred); 212 } 213 h->pred_mode_Y[pos] = predpred; 214 } 215 pred_mode_uv = get_ue_golomb(gb); 216 if(pred_mode_uv > 6) { 217 av_log(h->s.avctx, AV_LOG_ERROR, "illegal intra chroma pred mode\n"); 218 return -1; 219 } 220 ff_cavs_modify_mb_i(h, &pred_mode_uv); 221 222 /* get coded block pattern */ 223 if(h->pic_type == FF_I_TYPE) 224 cbp_code = get_ue_golomb(gb); 225 if(cbp_code > 63){ 226 av_log(h->s.avctx, AV_LOG_ERROR, "illegal intra cbp\n"); 227 return -1; 228 } 229 h->cbp = cbp_tab[cbp_code][0]; 230 if(h->cbp && !h->qp_fixed) 231 h->qp = (h->qp + get_se_golomb(gb)) & 63; //qp_delta 232 233 /* luma intra prediction interleaved with residual decode/transform/add */ 234 for(block=0;block<4;block++) { 235 d = h->cy + h->luma_scan[block]; 236 ff_cavs_load_intra_pred_luma(h, top, &left, block); 237 h->intra_pred_l[h->pred_mode_Y[ff_cavs_scan3x3[block]]] 238 (d, top, left, h->l_stride); 239 if(h->cbp & (1<<block)) 240 decode_residual_block(h,gb,ff_cavs_intra_dec,1,h->qp,d,h->l_stride); 241 } 242 243 /* chroma intra prediction */ 244 ff_cavs_load_intra_pred_chroma(h); 245 h->intra_pred_c[pred_mode_uv](h->cu, &h->top_border_u[h->mbx*10], 246 h->left_border_u, h->c_stride); 247 h->intra_pred_c[pred_mode_uv](h->cv, &h->top_border_v[h->mbx*10], 248 h->left_border_v, h->c_stride); 249 250 decode_residual_chroma(h); 251 ff_cavs_filter(h,I_8X8); 252 set_mv_intra(h); 253 return 0; 254} 255 256static void decode_mb_p(AVSContext *h, enum cavs_mb mb_type) { 257 GetBitContext *gb = &h->s.gb; 258 int ref[4]; 259 260 ff_cavs_init_mb(h); 261 switch(mb_type) { 262 case P_SKIP: 263 ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_PSKIP, BLK_16X16, 0); 264 break; 265 case P_16X16: 266 ref[0] = h->ref_flag ? 0 : get_bits1(gb); 267 ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16,ref[0]); 268 break; 269 case P_16X8: 270 ref[0] = h->ref_flag ? 0 : get_bits1(gb); 271 ref[2] = h->ref_flag ? 0 : get_bits1(gb); 272 ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_TOP, BLK_16X8, ref[0]); 273 ff_cavs_mv(h, MV_FWD_X2, MV_FWD_A1, MV_PRED_LEFT, BLK_16X8, ref[2]); 274 break; 275 case P_8X16: 276 ref[0] = h->ref_flag ? 0 : get_bits1(gb); 277 ref[1] = h->ref_flag ? 0 : get_bits1(gb); 278 ff_cavs_mv(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_LEFT, BLK_8X16, ref[0]); 279 ff_cavs_mv(h, MV_FWD_X1, MV_FWD_C2, MV_PRED_TOPRIGHT,BLK_8X16, ref[1]); 280 break; 281 case P_8X8: 282 ref[0] = h->ref_flag ? 0 : get_bits1(gb); 283 ref[1] = h->ref_flag ? 0 : get_bits1(gb); 284 ref[2] = h->ref_flag ? 0 : get_bits1(gb); 285 ref[3] = h->ref_flag ? 0 : get_bits1(gb); 286 ff_cavs_mv(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_MEDIAN, BLK_8X8, ref[0]); 287 ff_cavs_mv(h, MV_FWD_X1, MV_FWD_C2, MV_PRED_MEDIAN, BLK_8X8, ref[1]); 288 ff_cavs_mv(h, MV_FWD_X2, MV_FWD_X1, MV_PRED_MEDIAN, BLK_8X8, ref[2]); 289 ff_cavs_mv(h, MV_FWD_X3, MV_FWD_X0, MV_PRED_MEDIAN, BLK_8X8, ref[3]); 290 } 291 ff_cavs_inter(h, mb_type); 292 set_intra_mode_default(h); 293 store_mvs(h); 294 if(mb_type != P_SKIP) 295 decode_residual_inter(h); 296 ff_cavs_filter(h,mb_type); 297 h->col_type_base[h->mbidx] = mb_type; 298} 299 300static void decode_mb_b(AVSContext *h, enum cavs_mb mb_type) { 301 int block; 302 enum cavs_sub_mb sub_type[4]; 303 int flags; 304 305 ff_cavs_init_mb(h); 306 307 /* reset all MVs */ 308 h->mv[MV_FWD_X0] = ff_cavs_dir_mv; 309 set_mvs(&h->mv[MV_FWD_X0], BLK_16X16); 310 h->mv[MV_BWD_X0] = ff_cavs_dir_mv; 311 set_mvs(&h->mv[MV_BWD_X0], BLK_16X16); 312 switch(mb_type) { 313 case B_SKIP: 314 case B_DIRECT: 315 if(!h->col_type_base[h->mbidx]) { 316 /* intra MB at co-location, do in-plane prediction */ 317 ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_BSKIP, BLK_16X16, 1); 318 ff_cavs_mv(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_BSKIP, BLK_16X16, 0); 319 } else 320 /* direct prediction from co-located P MB, block-wise */ 321 for(block=0;block<4;block++) 322 mv_pred_direct(h,&h->mv[mv_scan[block]], 323 &h->col_mv[h->mbidx*4 + block]); 324 break; 325 case B_FWD_16X16: 326 ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16, 1); 327 break; 328 case B_SYM_16X16: 329 ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16, 1); 330 mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_16X16); 331 break; 332 case B_BWD_16X16: 333 ff_cavs_mv(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_MEDIAN, BLK_16X16, 0); 334 break; 335 case B_8X8: 336 for(block=0;block<4;block++) 337 sub_type[block] = get_bits(&h->s.gb,2); 338 for(block=0;block<4;block++) { 339 switch(sub_type[block]) { 340 case B_SUB_DIRECT: 341 if(!h->col_type_base[h->mbidx]) { 342 /* intra MB at co-location, do in-plane prediction */ 343 ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3, 344 MV_PRED_BSKIP, BLK_8X8, 1); 345 ff_cavs_mv(h, mv_scan[block]+MV_BWD_OFFS, 346 mv_scan[block]-3+MV_BWD_OFFS, 347 MV_PRED_BSKIP, BLK_8X8, 0); 348 } else 349 mv_pred_direct(h,&h->mv[mv_scan[block]], 350 &h->col_mv[h->mbidx*4 + block]); 351 break; 352 case B_SUB_FWD: 353 ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3, 354 MV_PRED_MEDIAN, BLK_8X8, 1); 355 break; 356 case B_SUB_SYM: 357 ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3, 358 MV_PRED_MEDIAN, BLK_8X8, 1); 359 mv_pred_sym(h, &h->mv[mv_scan[block]], BLK_8X8); 360 break; 361 } 362 } 363 for(block=0;block<4;block++) { 364 if(sub_type[block] == B_SUB_BWD) 365 ff_cavs_mv(h, mv_scan[block]+MV_BWD_OFFS, 366 mv_scan[block]+MV_BWD_OFFS-3, 367 MV_PRED_MEDIAN, BLK_8X8, 0); 368 } 369 break; 370 default: 371 assert((mb_type > B_SYM_16X16) && (mb_type < B_8X8)); 372 flags = ff_cavs_partition_flags[mb_type]; 373 if(mb_type & 1) { /* 16x8 macroblock types */ 374 if(flags & FWD0) 375 ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_TOP, BLK_16X8, 1); 376 if(flags & SYM0) 377 mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_16X8); 378 if(flags & FWD1) 379 ff_cavs_mv(h, MV_FWD_X2, MV_FWD_A1, MV_PRED_LEFT, BLK_16X8, 1); 380 if(flags & SYM1) 381 mv_pred_sym(h, &h->mv[MV_FWD_X2], BLK_16X8); 382 if(flags & BWD0) 383 ff_cavs_mv(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_TOP, BLK_16X8, 0); 384 if(flags & BWD1) 385 ff_cavs_mv(h, MV_BWD_X2, MV_BWD_A1, MV_PRED_LEFT, BLK_16X8, 0); 386 } else { /* 8x16 macroblock types */ 387 if(flags & FWD0) 388 ff_cavs_mv(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_LEFT, BLK_8X16, 1); 389 if(flags & SYM0) 390 mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_8X16); 391 if(flags & FWD1) 392 ff_cavs_mv(h,MV_FWD_X1,MV_FWD_C2,MV_PRED_TOPRIGHT,BLK_8X16,1); 393 if(flags & SYM1) 394 mv_pred_sym(h, &h->mv[MV_FWD_X1], BLK_8X16); 395 if(flags & BWD0) 396 ff_cavs_mv(h, MV_BWD_X0, MV_BWD_B3, MV_PRED_LEFT, BLK_8X16, 0); 397 if(flags & BWD1) 398 ff_cavs_mv(h,MV_BWD_X1,MV_BWD_C2,MV_PRED_TOPRIGHT,BLK_8X16,0); 399 } 400 } 401 ff_cavs_inter(h, mb_type); 402 set_intra_mode_default(h); 403 if(mb_type != B_SKIP) 404 decode_residual_inter(h); 405 ff_cavs_filter(h,mb_type); 406} 407 408/***************************************************************************** 409 * 410 * slice level 411 * 412 ****************************************************************************/ 413 414static inline int decode_slice_header(AVSContext *h, GetBitContext *gb) { 415 if(h->stc > 0xAF) 416 av_log(h->s.avctx, AV_LOG_ERROR, "unexpected start code 0x%02x\n", h->stc); 417 h->mby = h->stc; 418 h->mbidx = h->mby*h->mb_width; 419 420 /* mark top macroblocks as unavailable */ 421 h->flags &= ~(B_AVAIL|C_AVAIL); 422 if((h->mby == 0) && (!h->qp_fixed)){ 423 h->qp_fixed = get_bits1(gb); 424 h->qp = get_bits(gb,6); 425 } 426 /* inter frame or second slice can have weighting params */ 427 if((h->pic_type != FF_I_TYPE) || (!h->pic_structure && h->mby >= h->mb_width/2)) 428 if(get_bits1(gb)) { //slice_weighting_flag 429 av_log(h->s.avctx, AV_LOG_ERROR, 430 "weighted prediction not yet supported\n"); 431 } 432 return 0; 433} 434 435static inline int check_for_slice(AVSContext *h) { 436 GetBitContext *gb = &h->s.gb; 437 int align; 438 439 if(h->mbx) 440 return 0; 441 align = (-get_bits_count(gb)) & 7; 442 /* check for stuffing byte */ 443 if(!align && (show_bits(gb,8) == 0x80)) 444 align = 8; 445 if((show_bits_long(gb,24+align) & 0xFFFFFF) == 0x000001) { 446 skip_bits_long(gb,24+align); 447 h->stc = get_bits(gb,8); 448 decode_slice_header(h,gb); 449 return 1; 450 } 451 return 0; 452} 453 454/***************************************************************************** 455 * 456 * frame level 457 * 458 ****************************************************************************/ 459 460static int decode_pic(AVSContext *h) { 461 MpegEncContext *s = &h->s; 462 int skip_count = -1; 463 enum cavs_mb mb_type; 464 465 if (!s->context_initialized) { 466 s->avctx->idct_algo = FF_IDCT_CAVS; 467 if (MPV_common_init(s) < 0) 468 return -1; 469 ff_init_scantable(s->dsp.idct_permutation,&h->scantable,ff_zigzag_direct); 470 } 471 skip_bits(&s->gb,16);//bbv_dwlay 472 if(h->stc == PIC_PB_START_CODE) { 473 h->pic_type = get_bits(&s->gb,2) + FF_I_TYPE; 474 if(h->pic_type > FF_B_TYPE) { 475 av_log(s->avctx, AV_LOG_ERROR, "illegal picture type\n"); 476 return -1; 477 } 478 /* make sure we have the reference frames we need */ 479 if(!h->DPB[0].data[0] || 480 (!h->DPB[1].data[0] && h->pic_type == FF_B_TYPE)) 481 return -1; 482 } else { 483 h->pic_type = FF_I_TYPE; 484 if(get_bits1(&s->gb)) 485 skip_bits(&s->gb,24);//time_code 486 /* old sample clips were all progressive and no low_delay, 487 bump stream revision if detected otherwise */ 488 if((s->low_delay) || !(show_bits(&s->gb,9) & 1)) 489 h->stream_revision = 1; 490 /* similarly test top_field_first and repeat_first_field */ 491 else if(show_bits(&s->gb,11) & 3) 492 h->stream_revision = 1; 493 if(h->stream_revision > 0) 494 skip_bits(&s->gb,1); //marker_bit 495 } 496 /* release last B frame */ 497 if(h->picture.data[0]) 498 s->avctx->release_buffer(s->avctx, (AVFrame *)&h->picture); 499 500 s->avctx->get_buffer(s->avctx, (AVFrame *)&h->picture); 501 ff_cavs_init_pic(h); 502 h->picture.poc = get_bits(&s->gb,8)*2; 503 504 /* get temporal distances and MV scaling factors */ 505 if(h->pic_type != FF_B_TYPE) { 506 h->dist[0] = (h->picture.poc - h->DPB[0].poc + 512) % 512; 507 } else { 508 h->dist[0] = (h->DPB[0].poc - h->picture.poc + 512) % 512; 509 } 510 h->dist[1] = (h->picture.poc - h->DPB[1].poc + 512) % 512; 511 h->scale_den[0] = h->dist[0] ? 512/h->dist[0] : 0; 512 h->scale_den[1] = h->dist[1] ? 512/h->dist[1] : 0; 513 if(h->pic_type == FF_B_TYPE) { 514 h->sym_factor = h->dist[0]*h->scale_den[1]; 515 } else { 516 h->direct_den[0] = h->dist[0] ? 16384/h->dist[0] : 0; 517 h->direct_den[1] = h->dist[1] ? 16384/h->dist[1] : 0; 518 } 519 520 if(s->low_delay) 521 get_ue_golomb(&s->gb); //bbv_check_times 522 h->progressive = get_bits1(&s->gb); 523 h->pic_structure = 1; 524 if(!h->progressive) 525 h->pic_structure = get_bits1(&s->gb); 526 if(!h->pic_structure && h->stc == PIC_PB_START_CODE) 527 skip_bits1(&s->gb); //advanced_pred_mode_disable 528 skip_bits1(&s->gb); //top_field_first 529 skip_bits1(&s->gb); //repeat_first_field 530 h->qp_fixed = get_bits1(&s->gb); 531 h->qp = get_bits(&s->gb,6); 532 if(h->pic_type == FF_I_TYPE) { 533 if(!h->progressive && !h->pic_structure) 534 skip_bits1(&s->gb);//what is this? 535 skip_bits(&s->gb,4); //reserved bits 536 } else { 537 if(!(h->pic_type == FF_B_TYPE && h->pic_structure == 1)) 538 h->ref_flag = get_bits1(&s->gb); 539 skip_bits(&s->gb,4); //reserved bits 540 h->skip_mode_flag = get_bits1(&s->gb); 541 } 542 h->loop_filter_disable = get_bits1(&s->gb); 543 if(!h->loop_filter_disable && get_bits1(&s->gb)) { 544 h->alpha_offset = get_se_golomb(&s->gb); 545 h->beta_offset = get_se_golomb(&s->gb); 546 } else { 547 h->alpha_offset = h->beta_offset = 0; 548 } 549 if(h->pic_type == FF_I_TYPE) { 550 do { 551 check_for_slice(h); 552 decode_mb_i(h, 0); 553 } while(ff_cavs_next_mb(h)); 554 } else if(h->pic_type == FF_P_TYPE) { 555 do { 556 if(check_for_slice(h)) 557 skip_count = -1; 558 if(h->skip_mode_flag && (skip_count < 0)) 559 skip_count = get_ue_golomb(&s->gb); 560 if(h->skip_mode_flag && skip_count--) { 561 decode_mb_p(h,P_SKIP); 562 } else { 563 mb_type = get_ue_golomb(&s->gb) + P_SKIP + h->skip_mode_flag; 564 if(mb_type > P_8X8) 565 decode_mb_i(h, mb_type - P_8X8 - 1); 566 else 567 decode_mb_p(h,mb_type); 568 } 569 } while(ff_cavs_next_mb(h)); 570 } else { /* FF_B_TYPE */ 571 do { 572 if(check_for_slice(h)) 573 skip_count = -1; 574 if(h->skip_mode_flag && (skip_count < 0)) 575 skip_count = get_ue_golomb(&s->gb); 576 if(h->skip_mode_flag && skip_count--) { 577 decode_mb_b(h,B_SKIP); 578 } else { 579 mb_type = get_ue_golomb(&s->gb) + B_SKIP + h->skip_mode_flag; 580 if(mb_type > B_8X8) 581 decode_mb_i(h, mb_type - B_8X8 - 1); 582 else 583 decode_mb_b(h,mb_type); 584 } 585 } while(ff_cavs_next_mb(h)); 586 } 587 if(h->pic_type != FF_B_TYPE) { 588 if(h->DPB[1].data[0]) 589 s->avctx->release_buffer(s->avctx, (AVFrame *)&h->DPB[1]); 590 h->DPB[1] = h->DPB[0]; 591 h->DPB[0] = h->picture; 592 memset(&h->picture,0,sizeof(Picture)); 593 } 594 return 0; 595} 596 597/***************************************************************************** 598 * 599 * headers and interface 600 * 601 ****************************************************************************/ 602 603static int decode_seq_header(AVSContext *h) { 604 MpegEncContext *s = &h->s; 605 int frame_rate_code; 606 607 h->profile = get_bits(&s->gb,8); 608 h->level = get_bits(&s->gb,8); 609 skip_bits1(&s->gb); //progressive sequence 610 s->width = get_bits(&s->gb,14); 611 s->height = get_bits(&s->gb,14); 612 skip_bits(&s->gb,2); //chroma format 613 skip_bits(&s->gb,3); //sample_precision 614 h->aspect_ratio = get_bits(&s->gb,4); 615 frame_rate_code = get_bits(&s->gb,4); 616 skip_bits(&s->gb,18);//bit_rate_lower 617 skip_bits1(&s->gb); //marker_bit 618 skip_bits(&s->gb,12);//bit_rate_upper 619 s->low_delay = get_bits1(&s->gb); 620 h->mb_width = (s->width + 15) >> 4; 621 h->mb_height = (s->height + 15) >> 4; 622 h->s.avctx->time_base.den = ff_frame_rate_tab[frame_rate_code].num; 623 h->s.avctx->time_base.num = ff_frame_rate_tab[frame_rate_code].den; 624 h->s.avctx->width = s->width; 625 h->s.avctx->height = s->height; 626 if(!h->top_qp) 627 ff_cavs_init_top_lines(h); 628 return 0; 629} 630 631static void cavs_flush(AVCodecContext * avctx) { 632 AVSContext *h = avctx->priv_data; 633 h->got_keyframe = 0; 634} 635 636static int cavs_decode_frame(AVCodecContext * avctx,void *data, int *data_size, 637 AVPacket *avpkt) { 638 const uint8_t *buf = avpkt->data; 639 int buf_size = avpkt->size; 640 AVSContext *h = avctx->priv_data; 641 MpegEncContext *s = &h->s; 642 int input_size; 643 const uint8_t *buf_end; 644 const uint8_t *buf_ptr; 645 AVFrame *picture = data; 646 uint32_t stc = -1; 647 648 s->avctx = avctx; 649 650 if (buf_size == 0) { 651 if(!s->low_delay && h->DPB[0].data[0]) { 652 *data_size = sizeof(AVPicture); 653 *picture = *(AVFrame *) &h->DPB[0]; 654 } 655 return 0; 656 } 657 658 buf_ptr = buf; 659 buf_end = buf + buf_size; 660 for(;;) { 661 buf_ptr = ff_find_start_code(buf_ptr,buf_end, &stc); 662 if(stc & 0xFFFFFE00) 663 return FFMAX(0, buf_ptr - buf - s->parse_context.last_index); 664 input_size = (buf_end - buf_ptr)*8; 665 switch(stc) { 666 case CAVS_START_CODE: 667 init_get_bits(&s->gb, buf_ptr, input_size); 668 decode_seq_header(h); 669 break; 670 case PIC_I_START_CODE: 671 if(!h->got_keyframe) { 672 if(h->DPB[0].data[0]) 673 avctx->release_buffer(avctx, (AVFrame *)&h->DPB[0]); 674 if(h->DPB[1].data[0]) 675 avctx->release_buffer(avctx, (AVFrame *)&h->DPB[1]); 676 h->got_keyframe = 1; 677 } 678 case PIC_PB_START_CODE: 679 *data_size = 0; 680 if(!h->got_keyframe) 681 break; 682 init_get_bits(&s->gb, buf_ptr, input_size); 683 h->stc = stc; 684 if(decode_pic(h)) 685 break; 686 *data_size = sizeof(AVPicture); 687 if(h->pic_type != FF_B_TYPE) { 688 if(h->DPB[1].data[0]) { 689 *picture = *(AVFrame *) &h->DPB[1]; 690 } else { 691 *data_size = 0; 692 } 693 } else 694 *picture = *(AVFrame *) &h->picture; 695 break; 696 case EXT_START_CODE: 697 //mpeg_decode_extension(avctx,buf_ptr, input_size); 698 break; 699 case USER_START_CODE: 700 //mpeg_decode_user_data(avctx,buf_ptr, input_size); 701 break; 702 default: 703 if (stc <= SLICE_MAX_START_CODE) { 704 init_get_bits(&s->gb, buf_ptr, input_size); 705 decode_slice_header(h, &s->gb); 706 } 707 break; 708 } 709 } 710} 711 712AVCodec cavs_decoder = { 713 "cavs", 714 AVMEDIA_TYPE_VIDEO, 715 CODEC_ID_CAVS, 716 sizeof(AVSContext), 717 ff_cavs_init, 718 NULL, 719 ff_cavs_end, 720 cavs_decode_frame, 721 CODEC_CAP_DR1 | CODEC_CAP_DELAY, 722 .flush= cavs_flush, 723 .long_name= NULL_IF_CONFIG_SMALL("Chinese AVS video (AVS1-P2, JiZhun profile)"), 724}; 725