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ffmpeg / libavcodec / cavsdec.c @ 2912e87a

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1
/*
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 * Chinese AVS video (AVS1-P2, JiZhun profile) decoder.
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 * Copyright (c) 2006  Stefan Gehrer <stefan.gehrer@gmx.de>
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
21

    
22
/**
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 * @file
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 * Chinese AVS video (AVS1-P2, JiZhun profile) decoder
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 * @author Stefan Gehrer <stefan.gehrer@gmx.de>
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 */
27

    
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#include "avcodec.h"
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#include "get_bits.h"
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#include "golomb.h"
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#include "cavs.h"
32

    
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static const uint8_t mv_scan[4] = {
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    MV_FWD_X0,MV_FWD_X1,
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    MV_FWD_X2,MV_FWD_X3
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};
37

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

    
49
/*****************************************************************************
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 *
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 * motion vector prediction
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 *
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 ****************************************************************************/
54

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

    
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static inline void mv_pred_direct(AVSContext *h, cavs_vector *pmv_fw,
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                                  cavs_vector *col_mv) {
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    cavs_vector *pmv_bw = pmv_fw + MV_BWD_OFFS;
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    int den = h->direct_den[col_mv->ref];
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    int m = col_mv->x >> 31;
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    pmv_fw->dist = h->dist[1];
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    pmv_bw->dist = h->dist[0];
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    pmv_fw->ref = 1;
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    pmv_bw->ref = 0;
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    /* scale the co-located motion vector according to its temporal span */
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    pmv_fw->x = (((den+(den*col_mv->x*pmv_fw->dist^m)-m-1)>>14)^m)-m;
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    pmv_bw->x = m-(((den+(den*col_mv->x*pmv_bw->dist^m)-m-1)>>14)^m);
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    m = col_mv->y >> 31;
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    pmv_fw->y = (((den+(den*col_mv->y*pmv_fw->dist^m)-m-1)>>14)^m)-m;
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    pmv_bw->y = m-(((den+(den*col_mv->y*pmv_bw->dist^m)-m-1)>>14)^m);
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}
79

    
80
static inline void mv_pred_sym(AVSContext *h, cavs_vector *src, enum cavs_block size) {
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    cavs_vector *dst = src + MV_BWD_OFFS;
82

    
83
    /* backward mv is the scaled and negated forward mv */
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    dst->x = -((src->x * h->sym_factor + 256) >> 9);
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    dst->y = -((src->y * h->sym_factor + 256) >> 9);
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    dst->ref = 0;
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    dst->dist = h->dist[0];
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    set_mvs(dst, size);
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}
90

    
91
/*****************************************************************************
92
 *
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 * residual data decoding
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 *
95
 ****************************************************************************/
96

    
97
/** kth-order exponential golomb code */
98
static 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
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 *  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
 */
115
static int decode_residual_block(AVSContext *h, GetBitContext *gb,
116
                                 const struct dec_2dvlc *r, int esc_golomb_order,
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                                 int qp, uint8_t *dst, int stride) {
118
    int i, level_code, esc_code, level, run, mask;
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    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;
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            esc_code = get_ue_code(gb,esc_golomb_order);
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            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->cdsp.cavs_idct8_add(dst,block,stride);
147
    h->s.dsp.clear_block(block);
148
    return 0;
149
}
150

    
151

    
152
static 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

    
161
static 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

    
190
static 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

    
256
static 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

    
300
static 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

    
414
static 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

    
435
static 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

    
460
static 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

    
603
static 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

    
631
static void cavs_flush(AVCodecContext * avctx) {
632
    AVSContext *h = avctx->priv_data;
633
    h->got_keyframe = 0;
634
}
635

    
636
static 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

    
712
AVCodec ff_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
};