cavsdec.c 25.8 KB
Newer Older
1 2 3 4
/*
 * Chinese AVS video (AVS1-P2, JiZhun profile) decoder.
 * Copyright (c) 2006  Stefan Gehrer <stefan.gehrer@gmx.de>
 *
5
 * This file is part of Libav.
6
 *
7
 * Libav is free software; you can redistribute it and/or
8 9 10 11
 * 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.
 *
12
 * Libav is distributed in the hope that it will be useful,
13 14 15 16 17
 * 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
18
 * License along with Libav; if not, write to the Free Software
19 20 21 22
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
23
 * @file
24 25 26 27 28
 * Chinese AVS video (AVS1-P2, JiZhun profile) decoder
 * @author Stefan Gehrer <stefan.gehrer@gmx.de>
 */

#include "avcodec.h"
29
#include "get_bits.h"
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55
#include "golomb.h"
#include "cavs.h"

static const uint8_t mv_scan[4] = {
    MV_FWD_X0,MV_FWD_X1,
    MV_FWD_X2,MV_FWD_X3
};

static const uint8_t cbp_tab[64][2] = {
  {63, 0},{15,15},{31,63},{47,31},{ 0,16},{14,32},{13,47},{11,13},
  { 7,14},{ 5,11},{10,12},{ 8, 5},{12,10},{61, 7},{ 4,48},{55, 3},
  { 1, 2},{ 2, 8},{59, 4},{ 3, 1},{62,61},{ 9,55},{ 6,59},{29,62},
  {45,29},{51,27},{23,23},{39,19},{27,30},{46,28},{53, 9},{30, 6},
  {43,60},{37,21},{60,44},{16,26},{21,51},{28,35},{19,18},{35,20},
  {42,24},{26,53},{44,17},{32,37},{58,39},{24,45},{20,58},{17,43},
  {18,42},{48,46},{22,36},{33,33},{25,34},{49,40},{40,52},{36,49},
  {34,50},{50,56},{52,25},{54,22},{41,54},{56,57},{38,41},{57,38}
};

/*****************************************************************************
 *
 * motion vector prediction
 *
 ****************************************************************************/

static inline void store_mvs(AVSContext *h) {
56 57 58 59
    h->col_mv[h->mbidx*4 + 0] = h->mv[MV_FWD_X0];
    h->col_mv[h->mbidx*4 + 1] = h->mv[MV_FWD_X1];
    h->col_mv[h->mbidx*4 + 2] = h->mv[MV_FWD_X2];
    h->col_mv[h->mbidx*4 + 3] = h->mv[MV_FWD_X3];
60 61
}

62 63 64
static inline void mv_pred_direct(AVSContext *h, cavs_vector *pmv_fw,
                                  cavs_vector *col_mv) {
    cavs_vector *pmv_bw = pmv_fw + MV_BWD_OFFS;
65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
    int den = h->direct_den[col_mv->ref];
    int m = col_mv->x >> 31;

    pmv_fw->dist = h->dist[1];
    pmv_bw->dist = h->dist[0];
    pmv_fw->ref = 1;
    pmv_bw->ref = 0;
    /* scale the co-located motion vector according to its temporal span */
    pmv_fw->x = (((den+(den*col_mv->x*pmv_fw->dist^m)-m-1)>>14)^m)-m;
    pmv_bw->x = m-(((den+(den*col_mv->x*pmv_bw->dist^m)-m-1)>>14)^m);
    m = col_mv->y >> 31;
    pmv_fw->y = (((den+(den*col_mv->y*pmv_fw->dist^m)-m-1)>>14)^m)-m;
    pmv_bw->y = m-(((den+(den*col_mv->y*pmv_bw->dist^m)-m-1)>>14)^m);
}

80
static inline void mv_pred_sym(AVSContext *h, cavs_vector *src, enum cavs_block size) {
81
    cavs_vector *dst = src + MV_BWD_OFFS;
82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115

    /* backward mv is the scaled and negated forward mv */
    dst->x = -((src->x * h->sym_factor + 256) >> 9);
    dst->y = -((src->y * h->sym_factor + 256) >> 9);
    dst->ref = 0;
    dst->dist = h->dist[0];
    set_mvs(dst, size);
}

/*****************************************************************************
 *
 * residual data decoding
 *
 ****************************************************************************/

/** kth-order exponential golomb code */
static inline int get_ue_code(GetBitContext *gb, int order) {
    if(order) {
        int ret = get_ue_golomb(gb) << order;
        return ret + get_bits(gb,order);
    }
    return get_ue_golomb(gb);
}

/**
 * decode coefficients from one 8x8 block, dequantize, inverse transform
 *  and add them to sample block
 * @param r pointer to 2D VLC table
 * @param esc_golomb_order escape codes are k-golomb with this order k
 * @param qp quantizer
 * @param dst location of sample block
 * @param stride line stride in frame buffer
 */
static int decode_residual_block(AVSContext *h, GetBitContext *gb,
116
                                 const struct dec_2dvlc *r, int esc_golomb_order,
117 118
                                 int qp, uint8_t *dst, int stride) {
    int i, level_code, esc_code, level, run, mask;
119 120
    DCTELEM level_buf[65];
    uint8_t run_buf[65];
121 122 123 124 125 126 127 128 129 130 131 132
    DCTELEM *block = h->block;

    for(i=0;i<65;i++) {
        level_code = get_ue_code(gb,r->golomb_order);
        if(level_code >= ESCAPE_CODE) {
            run = ((level_code - ESCAPE_CODE) >> 1) + 1;
            esc_code = get_ue_code(gb,esc_golomb_order);
            level = esc_code + (run > r->max_run ? 1 : r->level_add[run]);
            while(level > r->inc_limit)
                r++;
            mask = -(level_code & 1);
            level = (level^mask) - mask;
133
        } else if (level_code >= 0) {
134 135 136 137 138
            level = r->rltab[level_code][0];
            if(!level) //end of block signal
                break;
            run   = r->rltab[level_code][1];
            r += r->rltab[level_code][2];
139 140
        } else {
            break;
141 142 143 144 145 146 147
        }
        level_buf[i] = level;
        run_buf[i] = run;
    }
    if(dequant(h,level_buf, run_buf, block, ff_cavs_dequant_mul[qp],
               ff_cavs_dequant_shift[qp], i))
        return -1;
148
    h->cdsp.cavs_idct8_add(dst,block,stride);
149
    h->s.dsp.clear_block(block);
150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193
    return 0;
}


static inline void decode_residual_chroma(AVSContext *h) {
    if(h->cbp & (1<<4))
        decode_residual_block(h,&h->s.gb,ff_cavs_chroma_dec,0,
                              ff_cavs_chroma_qp[h->qp],h->cu,h->c_stride);
    if(h->cbp & (1<<5))
        decode_residual_block(h,&h->s.gb,ff_cavs_chroma_dec,0,
                              ff_cavs_chroma_qp[h->qp],h->cv,h->c_stride);
}

static inline int decode_residual_inter(AVSContext *h) {
    int block;

    /* get coded block pattern */
    int cbp= get_ue_golomb(&h->s.gb);
    if(cbp > 63){
        av_log(h->s.avctx, AV_LOG_ERROR, "illegal inter cbp\n");
        return -1;
    }
    h->cbp = cbp_tab[cbp][1];

    /* get quantizer */
    if(h->cbp && !h->qp_fixed)
        h->qp = (h->qp + get_se_golomb(&h->s.gb)) & 63;
    for(block=0;block<4;block++)
        if(h->cbp & (1<<block))
            decode_residual_block(h,&h->s.gb,ff_cavs_inter_dec,0,h->qp,
                                  h->cy + h->luma_scan[block], h->l_stride);
    decode_residual_chroma(h);

    return 0;
}

/*****************************************************************************
 *
 * macroblock level
 *
 ****************************************************************************/

static int decode_mb_i(AVSContext *h, int cbp_code) {
    GetBitContext *gb = &h->s.gb;
194 195
    unsigned pred_mode_uv;
    int block;
196 197 198 199
    uint8_t top[18];
    uint8_t *left = NULL;
    uint8_t *d;

200
    ff_cavs_init_mb(h);
201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222

    /* get intra prediction modes from stream */
    for(block=0;block<4;block++) {
        int nA,nB,predpred;
        int pos = ff_cavs_scan3x3[block];

        nA = h->pred_mode_Y[pos-1];
        nB = h->pred_mode_Y[pos-3];
        predpred = FFMIN(nA,nB);
        if(predpred == NOT_AVAIL) // if either is not available
            predpred = INTRA_L_LP;
        if(!get_bits1(gb)){
            int rem_mode= get_bits(gb, 2);
            predpred = rem_mode + (rem_mode >= predpred);
        }
        h->pred_mode_Y[pos] = predpred;
    }
    pred_mode_uv = get_ue_golomb(gb);
    if(pred_mode_uv > 6) {
        av_log(h->s.avctx, AV_LOG_ERROR, "illegal intra chroma pred mode\n");
        return -1;
    }
223
    ff_cavs_modify_mb_i(h, &pred_mode_uv);
224 225

    /* get coded block pattern */
226
    if(h->pic_type == AV_PICTURE_TYPE_I)
227 228 229 230 231 232 233 234 235 236 237 238
        cbp_code = get_ue_golomb(gb);
    if(cbp_code > 63){
        av_log(h->s.avctx, AV_LOG_ERROR, "illegal intra cbp\n");
        return -1;
    }
    h->cbp = cbp_tab[cbp_code][0];
    if(h->cbp && !h->qp_fixed)
        h->qp = (h->qp + get_se_golomb(gb)) & 63; //qp_delta

    /* luma intra prediction interleaved with residual decode/transform/add */
    for(block=0;block<4;block++) {
        d = h->cy + h->luma_scan[block];
239
        ff_cavs_load_intra_pred_luma(h, top, &left, block);
240 241 242 243 244 245 246
        h->intra_pred_l[h->pred_mode_Y[ff_cavs_scan3x3[block]]]
            (d, top, left, h->l_stride);
        if(h->cbp & (1<<block))
            decode_residual_block(h,gb,ff_cavs_intra_dec,1,h->qp,d,h->l_stride);
    }

    /* chroma intra prediction */
247
    ff_cavs_load_intra_pred_chroma(h);
248 249 250 251 252 253 254 255 256 257 258
    h->intra_pred_c[pred_mode_uv](h->cu, &h->top_border_u[h->mbx*10],
                                  h->left_border_u, h->c_stride);
    h->intra_pred_c[pred_mode_uv](h->cv, &h->top_border_v[h->mbx*10],
                                  h->left_border_v, h->c_stride);

    decode_residual_chroma(h);
    ff_cavs_filter(h,I_8X8);
    set_mv_intra(h);
    return 0;
}

259
static void decode_mb_p(AVSContext *h, enum cavs_mb mb_type) {
260 261 262
    GetBitContext *gb = &h->s.gb;
    int ref[4];

263
    ff_cavs_init_mb(h);
264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299
    switch(mb_type) {
    case P_SKIP:
        ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_PSKIP,  BLK_16X16, 0);
        break;
    case P_16X16:
        ref[0] = h->ref_flag ? 0 : get_bits1(gb);
        ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16,ref[0]);
        break;
    case P_16X8:
        ref[0] = h->ref_flag ? 0 : get_bits1(gb);
        ref[2] = h->ref_flag ? 0 : get_bits1(gb);
        ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_TOP,    BLK_16X8, ref[0]);
        ff_cavs_mv(h, MV_FWD_X2, MV_FWD_A1, MV_PRED_LEFT,   BLK_16X8, ref[2]);
        break;
    case P_8X16:
        ref[0] = h->ref_flag ? 0 : get_bits1(gb);
        ref[1] = h->ref_flag ? 0 : get_bits1(gb);
        ff_cavs_mv(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_LEFT,   BLK_8X16, ref[0]);
        ff_cavs_mv(h, MV_FWD_X1, MV_FWD_C2, MV_PRED_TOPRIGHT,BLK_8X16, ref[1]);
        break;
    case P_8X8:
        ref[0] = h->ref_flag ? 0 : get_bits1(gb);
        ref[1] = h->ref_flag ? 0 : get_bits1(gb);
        ref[2] = h->ref_flag ? 0 : get_bits1(gb);
        ref[3] = h->ref_flag ? 0 : get_bits1(gb);
        ff_cavs_mv(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_MEDIAN,   BLK_8X8, ref[0]);
        ff_cavs_mv(h, MV_FWD_X1, MV_FWD_C2, MV_PRED_MEDIAN,   BLK_8X8, ref[1]);
        ff_cavs_mv(h, MV_FWD_X2, MV_FWD_X1, MV_PRED_MEDIAN,   BLK_8X8, ref[2]);
        ff_cavs_mv(h, MV_FWD_X3, MV_FWD_X0, MV_PRED_MEDIAN,   BLK_8X8, ref[3]);
    }
    ff_cavs_inter(h, mb_type);
    set_intra_mode_default(h);
    store_mvs(h);
    if(mb_type != P_SKIP)
        decode_residual_inter(h);
    ff_cavs_filter(h,mb_type);
300
    h->col_type_base[h->mbidx] = mb_type;
301 302
}

303
static void decode_mb_b(AVSContext *h, enum cavs_mb mb_type) {
304
    int block;
305
    enum cavs_sub_mb sub_type[4];
306 307
    int flags;

308
    ff_cavs_init_mb(h);
309 310 311 312 313 314 315 316 317

    /* reset all MVs */
    h->mv[MV_FWD_X0] = ff_cavs_dir_mv;
    set_mvs(&h->mv[MV_FWD_X0], BLK_16X16);
    h->mv[MV_BWD_X0] = ff_cavs_dir_mv;
    set_mvs(&h->mv[MV_BWD_X0], BLK_16X16);
    switch(mb_type) {
    case B_SKIP:
    case B_DIRECT:
318
        if(!h->col_type_base[h->mbidx]) {
319 320 321 322 323 324 325
            /* intra MB at co-location, do in-plane prediction */
            ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_BSKIP, BLK_16X16, 1);
            ff_cavs_mv(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_BSKIP, BLK_16X16, 0);
        } else
            /* direct prediction from co-located P MB, block-wise */
            for(block=0;block<4;block++)
                mv_pred_direct(h,&h->mv[mv_scan[block]],
326
                                 &h->col_mv[h->mbidx*4 + block]);
327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343
        break;
    case B_FWD_16X16:
        ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16, 1);
        break;
    case B_SYM_16X16:
        ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_MEDIAN, BLK_16X16, 1);
        mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_16X16);
        break;
    case B_BWD_16X16:
        ff_cavs_mv(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_MEDIAN, BLK_16X16, 0);
        break;
    case B_8X8:
        for(block=0;block<4;block++)
            sub_type[block] = get_bits(&h->s.gb,2);
        for(block=0;block<4;block++) {
            switch(sub_type[block]) {
            case B_SUB_DIRECT:
344
                if(!h->col_type_base[h->mbidx]) {
345 346 347 348 349 350 351 352
                    /* intra MB at co-location, do in-plane prediction */
                    ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3,
                            MV_PRED_BSKIP, BLK_8X8, 1);
                    ff_cavs_mv(h, mv_scan[block]+MV_BWD_OFFS,
                            mv_scan[block]-3+MV_BWD_OFFS,
                            MV_PRED_BSKIP, BLK_8X8, 0);
                } else
                    mv_pred_direct(h,&h->mv[mv_scan[block]],
353
                                   &h->col_mv[h->mbidx*4 + block]);
354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420
                break;
            case B_SUB_FWD:
                ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3,
                        MV_PRED_MEDIAN, BLK_8X8, 1);
                break;
            case B_SUB_SYM:
                ff_cavs_mv(h, mv_scan[block], mv_scan[block]-3,
                        MV_PRED_MEDIAN, BLK_8X8, 1);
                mv_pred_sym(h, &h->mv[mv_scan[block]], BLK_8X8);
                break;
            }
        }
        for(block=0;block<4;block++) {
            if(sub_type[block] == B_SUB_BWD)
                ff_cavs_mv(h, mv_scan[block]+MV_BWD_OFFS,
                        mv_scan[block]+MV_BWD_OFFS-3,
                        MV_PRED_MEDIAN, BLK_8X8, 0);
        }
        break;
    default:
        assert((mb_type > B_SYM_16X16) && (mb_type < B_8X8));
        flags = ff_cavs_partition_flags[mb_type];
        if(mb_type & 1) { /* 16x8 macroblock types */
            if(flags & FWD0)
                ff_cavs_mv(h, MV_FWD_X0, MV_FWD_C2, MV_PRED_TOP,  BLK_16X8, 1);
            if(flags & SYM0)
                mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_16X8);
            if(flags & FWD1)
                ff_cavs_mv(h, MV_FWD_X2, MV_FWD_A1, MV_PRED_LEFT, BLK_16X8, 1);
            if(flags & SYM1)
                mv_pred_sym(h, &h->mv[MV_FWD_X2], BLK_16X8);
            if(flags & BWD0)
                ff_cavs_mv(h, MV_BWD_X0, MV_BWD_C2, MV_PRED_TOP,  BLK_16X8, 0);
            if(flags & BWD1)
                ff_cavs_mv(h, MV_BWD_X2, MV_BWD_A1, MV_PRED_LEFT, BLK_16X8, 0);
        } else {          /* 8x16 macroblock types */
            if(flags & FWD0)
                ff_cavs_mv(h, MV_FWD_X0, MV_FWD_B3, MV_PRED_LEFT, BLK_8X16, 1);
            if(flags & SYM0)
                mv_pred_sym(h, &h->mv[MV_FWD_X0], BLK_8X16);
            if(flags & FWD1)
                ff_cavs_mv(h,MV_FWD_X1,MV_FWD_C2,MV_PRED_TOPRIGHT,BLK_8X16,1);
            if(flags & SYM1)
                mv_pred_sym(h, &h->mv[MV_FWD_X1], BLK_8X16);
            if(flags & BWD0)
                ff_cavs_mv(h, MV_BWD_X0, MV_BWD_B3, MV_PRED_LEFT, BLK_8X16, 0);
            if(flags & BWD1)
                ff_cavs_mv(h,MV_BWD_X1,MV_BWD_C2,MV_PRED_TOPRIGHT,BLK_8X16,0);
        }
    }
    ff_cavs_inter(h, mb_type);
    set_intra_mode_default(h);
    if(mb_type != B_SKIP)
        decode_residual_inter(h);
    ff_cavs_filter(h,mb_type);
}

/*****************************************************************************
 *
 * slice level
 *
 ****************************************************************************/

static inline int decode_slice_header(AVSContext *h, GetBitContext *gb) {
    if(h->stc > 0xAF)
        av_log(h->s.avctx, AV_LOG_ERROR, "unexpected start code 0x%02x\n", h->stc);
    h->mby = h->stc;
421
    h->mbidx = h->mby*h->mb_width;
422 423 424

    /* mark top macroblocks as unavailable */
    h->flags &= ~(B_AVAIL|C_AVAIL);
425 426 427 428 429
    if((h->mby == 0) && (!h->qp_fixed)){
        h->qp_fixed = get_bits1(gb);
        h->qp = get_bits(gb,6);
    }
    /* inter frame or second slice can have weighting params */
430
    if((h->pic_type != AV_PICTURE_TYPE_I) || (!h->pic_structure && h->mby >= h->mb_width/2))
431 432 433 434 435 436 437
        if(get_bits1(gb)) { //slice_weighting_flag
            av_log(h->s.avctx, AV_LOG_ERROR,
                   "weighted prediction not yet supported\n");
        }
    return 0;
}

438
static inline int check_for_slice(AVSContext *h) {
439 440
    GetBitContext *gb = &h->s.gb;
    int align;
441 442

    if(h->mbx)
443
        return 0;
444
    align = (-get_bits_count(gb)) & 7;
445 446
    /* check for stuffing byte */
    if(!align && (show_bits(gb,8) == 0x80))
447
        align = 8;
448
    if((show_bits_long(gb,24+align) & 0xFFFFFF) == 0x000001) {
449
        skip_bits_long(gb,24+align);
450
        h->stc = get_bits(gb,8);
451 452
        if (h->stc >= h->mb_height)
            return 0;
453
        decode_slice_header(h,gb);
454
        return 1;
455
    }
456
    return 0;
457 458 459 460 461 462 463 464 465 466
}

/*****************************************************************************
 *
 * frame level
 *
 ****************************************************************************/

static int decode_pic(AVSContext *h) {
    MpegEncContext *s = &h->s;
467
    int skip_count = -1;
468
    enum cavs_mb mb_type;
469 470 471 472 473 474 475

    if (!s->context_initialized) {
        s->avctx->idct_algo = FF_IDCT_CAVS;
        if (MPV_common_init(s) < 0)
            return -1;
        ff_init_scantable(s->dsp.idct_permutation,&h->scantable,ff_zigzag_direct);
    }
476
    skip_bits(&s->gb,16);//bbv_dwlay
477
    if(h->stc == PIC_PB_START_CODE) {
478 479
        h->pic_type = get_bits(&s->gb,2) + AV_PICTURE_TYPE_I;
        if(h->pic_type > AV_PICTURE_TYPE_B) {
480 481 482 483
            av_log(s->avctx, AV_LOG_ERROR, "illegal picture type\n");
            return -1;
        }
        /* make sure we have the reference frames we need */
484 485
        if(!h->DPB[0].f.data[0] ||
          (!h->DPB[1].f.data[0] && h->pic_type == AV_PICTURE_TYPE_B))
486 487
            return -1;
    } else {
488
        h->pic_type = AV_PICTURE_TYPE_I;
489
        if(get_bits1(&s->gb))
490
            skip_bits(&s->gb,24);//time_code
491 492
        /* old sample clips were all progressive and no low_delay,
           bump stream revision if detected otherwise */
493
        if (s->low_delay || !(show_bits(&s->gb,9) & 1))
494 495 496 497 498 499
            h->stream_revision = 1;
        /* similarly test top_field_first and repeat_first_field */
        else if(show_bits(&s->gb,11) & 3)
            h->stream_revision = 1;
        if(h->stream_revision > 0)
            skip_bits(&s->gb,1); //marker_bit
500 501
    }
    /* release last B frame */
502
    if(h->picture.f.data[0])
503 504 505 506 507 508 509
        s->avctx->release_buffer(s->avctx, (AVFrame *)&h->picture);

    s->avctx->get_buffer(s->avctx, (AVFrame *)&h->picture);
    ff_cavs_init_pic(h);
    h->picture.poc = get_bits(&s->gb,8)*2;

    /* get temporal distances and MV scaling factors */
510
    if(h->pic_type != AV_PICTURE_TYPE_B) {
511 512 513 514 515 516 517
        h->dist[0] = (h->picture.poc - h->DPB[0].poc  + 512) % 512;
    } else {
        h->dist[0] = (h->DPB[0].poc  - h->picture.poc + 512) % 512;
    }
    h->dist[1] = (h->picture.poc - h->DPB[1].poc  + 512) % 512;
    h->scale_den[0] = h->dist[0] ? 512/h->dist[0] : 0;
    h->scale_den[1] = h->dist[1] ? 512/h->dist[1] : 0;
518
    if(h->pic_type == AV_PICTURE_TYPE_B) {
519 520 521 522 523 524 525 526 527
        h->sym_factor = h->dist[0]*h->scale_den[1];
    } else {
        h->direct_den[0] = h->dist[0] ? 16384/h->dist[0] : 0;
        h->direct_den[1] = h->dist[1] ? 16384/h->dist[1] : 0;
    }

    if(s->low_delay)
        get_ue_golomb(&s->gb); //bbv_check_times
    h->progressive             = get_bits1(&s->gb);
528 529 530 531
    h->pic_structure = 1;
    if(!h->progressive)
        h->pic_structure = get_bits1(&s->gb);
    if(!h->pic_structure && h->stc == PIC_PB_START_CODE)
532
        skip_bits1(&s->gb);     //advanced_pred_mode_disable
533 534 535 536
    skip_bits1(&s->gb);        //top_field_first
    skip_bits1(&s->gb);        //repeat_first_field
    h->qp_fixed                = get_bits1(&s->gb);
    h->qp                      = get_bits(&s->gb,6);
537
    if(h->pic_type == AV_PICTURE_TYPE_I) {
538 539 540 541
        if(!h->progressive && !h->pic_structure)
            skip_bits1(&s->gb);//what is this?
        skip_bits(&s->gb,4);   //reserved bits
    } else {
542
        if(!(h->pic_type == AV_PICTURE_TYPE_B && h->pic_structure == 1))
543 544 545 546 547 548 549 550 551 552 553
            h->ref_flag        = get_bits1(&s->gb);
        skip_bits(&s->gb,4);   //reserved bits
        h->skip_mode_flag      = get_bits1(&s->gb);
    }
    h->loop_filter_disable     = get_bits1(&s->gb);
    if(!h->loop_filter_disable && get_bits1(&s->gb)) {
        h->alpha_offset        = get_se_golomb(&s->gb);
        h->beta_offset         = get_se_golomb(&s->gb);
    } else {
        h->alpha_offset = h->beta_offset  = 0;
    }
554
    if(h->pic_type == AV_PICTURE_TYPE_I) {
555
        do {
556
            check_for_slice(h);
557
            decode_mb_i(h, 0);
558
        } while(ff_cavs_next_mb(h));
559
    } else if(h->pic_type == AV_PICTURE_TYPE_P) {
560
        do {
561 562 563
            if(check_for_slice(h))
                skip_count = -1;
            if(h->skip_mode_flag && (skip_count < 0))
564
                skip_count = get_ue_golomb(&s->gb);
565 566 567 568 569 570 571 572 573
            if(h->skip_mode_flag && skip_count--) {
                decode_mb_p(h,P_SKIP);
            } else {
                mb_type = get_ue_golomb(&s->gb) + P_SKIP + h->skip_mode_flag;
                if(mb_type > P_8X8)
                    decode_mb_i(h, mb_type - P_8X8 - 1);
                else
                    decode_mb_p(h,mb_type);
            }
574
        } while(ff_cavs_next_mb(h));
575
    } else { /* AV_PICTURE_TYPE_B */
576
        do {
577 578 579
            if(check_for_slice(h))
                skip_count = -1;
            if(h->skip_mode_flag && (skip_count < 0))
580
                skip_count = get_ue_golomb(&s->gb);
581 582 583 584 585 586 587 588 589
            if(h->skip_mode_flag && skip_count--) {
                decode_mb_b(h,B_SKIP);
            } else {
                mb_type = get_ue_golomb(&s->gb) + B_SKIP + h->skip_mode_flag;
                if(mb_type > B_8X8)
                    decode_mb_i(h, mb_type - B_8X8 - 1);
                else
                    decode_mb_b(h,mb_type);
            }
590
        } while(ff_cavs_next_mb(h));
591
    }
592
    if(h->pic_type != AV_PICTURE_TYPE_B) {
593
        if(h->DPB[1].f.data[0])
594
            s->avctx->release_buffer(s->avctx, (AVFrame *)&h->DPB[1]);
595 596
        h->DPB[1] = h->DPB[0];
        h->DPB[0] = h->picture;
597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626
        memset(&h->picture,0,sizeof(Picture));
    }
    return 0;
}

/*****************************************************************************
 *
 * headers and interface
 *
 ****************************************************************************/

static int decode_seq_header(AVSContext *h) {
    MpegEncContext *s = &h->s;
    int frame_rate_code;

    h->profile =         get_bits(&s->gb,8);
    h->level =           get_bits(&s->gb,8);
    skip_bits1(&s->gb); //progressive sequence
    s->width =           get_bits(&s->gb,14);
    s->height =          get_bits(&s->gb,14);
    skip_bits(&s->gb,2); //chroma format
    skip_bits(&s->gb,3); //sample_precision
    h->aspect_ratio =    get_bits(&s->gb,4);
    frame_rate_code =    get_bits(&s->gb,4);
    skip_bits(&s->gb,18);//bit_rate_lower
    skip_bits1(&s->gb);  //marker_bit
    skip_bits(&s->gb,12);//bit_rate_upper
    s->low_delay =       get_bits1(&s->gb);
    h->mb_width  = (s->width  + 15) >> 4;
    h->mb_height = (s->height + 15) >> 4;
627 628
    h->s.avctx->time_base.den = avpriv_frame_rate_tab[frame_rate_code].num;
    h->s.avctx->time_base.num = avpriv_frame_rate_tab[frame_rate_code].den;
629 630 631 632 633 634 635 636 637 638 639 640 641
    h->s.avctx->width  = s->width;
    h->s.avctx->height = s->height;
    if(!h->top_qp)
        ff_cavs_init_top_lines(h);
    return 0;
}

static void cavs_flush(AVCodecContext * avctx) {
    AVSContext *h = avctx->priv_data;
    h->got_keyframe = 0;
}

static int cavs_decode_frame(AVCodecContext * avctx,void *data, int *data_size,
642 643 644
                             AVPacket *avpkt) {
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
645 646 647 648 649 650
    AVSContext *h = avctx->priv_data;
    MpegEncContext *s = &h->s;
    int input_size;
    const uint8_t *buf_end;
    const uint8_t *buf_ptr;
    AVFrame *picture = data;
651
    uint32_t stc = -1;
652 653 654 655

    s->avctx = avctx;

    if (buf_size == 0) {
656
        if (!s->low_delay && h->DPB[0].f.data[0]) {
657 658 659 660 661 662 663 664 665
            *data_size = sizeof(AVPicture);
            *picture = *(AVFrame *) &h->DPB[0];
        }
        return 0;
    }

    buf_ptr = buf;
    buf_end = buf + buf_size;
    for(;;) {
666
        buf_ptr = avpriv_mpv_find_start_code(buf_ptr,buf_end, &stc);
667
        if((stc & 0xFFFFFE00) || buf_ptr == buf_end)
668 669 670 671 672 673 674 675 676
            return FFMAX(0, buf_ptr - buf - s->parse_context.last_index);
        input_size = (buf_end - buf_ptr)*8;
        switch(stc) {
        case CAVS_START_CODE:
            init_get_bits(&s->gb, buf_ptr, input_size);
            decode_seq_header(h);
            break;
        case PIC_I_START_CODE:
            if(!h->got_keyframe) {
677
                if(h->DPB[0].f.data[0])
678
                    avctx->release_buffer(avctx, (AVFrame *)&h->DPB[0]);
679
                if(h->DPB[1].f.data[0])
680 681 682 683 684 685 686 687 688 689 690 691
                    avctx->release_buffer(avctx, (AVFrame *)&h->DPB[1]);
                h->got_keyframe = 1;
            }
        case PIC_PB_START_CODE:
            *data_size = 0;
            if(!h->got_keyframe)
                break;
            init_get_bits(&s->gb, buf_ptr, input_size);
            h->stc = stc;
            if(decode_pic(h))
                break;
            *data_size = sizeof(AVPicture);
692
            if(h->pic_type != AV_PICTURE_TYPE_B) {
693
                if(h->DPB[1].f.data[0]) {
694 695 696 697 698 699 700 701 702 703 704 705 706 707
                    *picture = *(AVFrame *) &h->DPB[1];
                } else {
                    *data_size = 0;
                }
            } else
                *picture = *(AVFrame *) &h->picture;
            break;
        case EXT_START_CODE:
            //mpeg_decode_extension(avctx,buf_ptr, input_size);
            break;
        case USER_START_CODE:
            //mpeg_decode_user_data(avctx,buf_ptr, input_size);
            break;
        default:
708
            if (stc <= SLICE_MAX_START_CODE) {
709 710 711 712 713 714 715 716
                init_get_bits(&s->gb, buf_ptr, input_size);
                decode_slice_header(h, &s->gb);
            }
            break;
        }
    }
}

717
AVCodec ff_cavs_decoder = {
718 719 720 721 722 723 724 725
    .name           = "cavs",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = CODEC_ID_CAVS,
    .priv_data_size = sizeof(AVSContext),
    .init           = ff_cavs_init,
    .close          = ff_cavs_end,
    .decode         = cavs_decode_frame,
    .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_DELAY,
726
    .flush= cavs_flush,
727
    .long_name= NULL_IF_CONFIG_SMALL("Chinese AVS video (AVS1-P2, JiZhun profile)"),
728
};