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ffmpeg / libavcodec / mpeg12.c @ 03987173

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1
/*
2
 * MPEG1 encoder / MPEG2 decoder
3
 * Copyright (c) 2000,2001 Fabrice Bellard.
4
 *
5
 * This library is free software; you can redistribute it and/or
6
 * modify it under the terms of the GNU Lesser General Public
7
 * License as published by the Free Software Foundation; either
8
 * version 2 of the License, or (at your option) any later version.
9
 *
10
 * This library is distributed in the hope that it will be useful,
11
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13
 * Lesser General Public License for more details.
14
 *
15
 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18
 */
19
//#define DEBUG
20
#include "avcodec.h"
21
#include "dsputil.h"
22
#include "mpegvideo.h"
23

    
24
#include "mpeg12data.h"
25

    
26
/* Start codes. */
27
#define SEQ_END_CODE                0x000001b7
28
#define SEQ_START_CODE                0x000001b3
29
#define GOP_START_CODE                0x000001b8
30
#define PICTURE_START_CODE        0x00000100
31
#define SLICE_MIN_START_CODE        0x00000101
32
#define SLICE_MAX_START_CODE        0x000001af
33
#define EXT_START_CODE                0x000001b5
34
#define USER_START_CODE                0x000001b2
35

    
36
static void mpeg1_encode_block(MpegEncContext *s, 
37
                         DCTELEM *block, 
38
                         int component);
39
static void mpeg1_encode_motion(MpegEncContext *s, int val);
40
static void mpeg1_skip_picture(MpegEncContext *s, int pict_num);
41
static int mpeg1_decode_block(MpegEncContext *s, 
42
                              DCTELEM *block, 
43
                              int n);
44
static int mpeg2_decode_block_non_intra(MpegEncContext *s, 
45
                                        DCTELEM *block, 
46
                                        int n);
47
static int mpeg2_decode_block_intra(MpegEncContext *s, 
48
                                    DCTELEM *block, 
49
                                    int n);
50
static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred);
51

    
52
static UINT16 mv_penalty[MAX_FCODE+1][MAX_MV*2+1];
53
static UINT8 fcode_tab[MAX_MV*2+1];
54

    
55
static void put_header(MpegEncContext *s, int header)
56
{
57
    align_put_bits(&s->pb);
58
    put_bits(&s->pb, 16, header>>16);
59
    put_bits(&s->pb, 16, header&0xFFFF);
60
}
61

    
62
/* put sequence header if needed */
63
static void mpeg1_encode_sequence_header(MpegEncContext *s)
64
{
65
        unsigned int vbv_buffer_size;
66
        unsigned int fps, v;
67
        int n;
68
        UINT64 time_code;
69
        
70
        if (s->picture_in_gop_number == 0) {
71
            /* mpeg1 header repeated every gop */
72
            put_header(s, SEQ_START_CODE);
73
            
74
            /* search closest frame rate */
75
            {
76
                int i, dmin, d;
77
                s->frame_rate_index = 0;
78
                dmin = 0x7fffffff;
79
                for(i=1;i<9;i++) {
80
                    d = abs(s->frame_rate - frame_rate_tab[i]);
81
                    if (d < dmin) {
82
                        dmin = d;
83
                        s->frame_rate_index = i;
84
                    }
85
                }
86
            }
87
 
88
            put_bits(&s->pb, 12, s->width);
89
            put_bits(&s->pb, 12, s->height);
90
            put_bits(&s->pb, 4, 1); /* 1/1 aspect ratio */
91
            put_bits(&s->pb, 4, s->frame_rate_index);
92
            v = s->bit_rate / 400;
93
            if (v > 0x3ffff)
94
                v = 0x3ffff;
95
            put_bits(&s->pb, 18, v);
96
            put_bits(&s->pb, 1, 1); /* marker */
97
            /* vbv buffer size: slightly greater than an I frame. We add
98
               some margin just in case */
99
            vbv_buffer_size = (3 * s->I_frame_bits) / (2 * 8);
100
            put_bits(&s->pb, 10, (vbv_buffer_size + 16383) / 16384); 
101
            put_bits(&s->pb, 1, 1); /* constrained parameter flag */
102
            put_bits(&s->pb, 1, 0); /* no custom intra matrix */
103
            put_bits(&s->pb, 1, 0); /* no custom non intra matrix */
104

    
105
            put_header(s, GOP_START_CODE);
106
            put_bits(&s->pb, 1, 0); /* do drop frame */
107
            /* time code : we must convert from the real frame rate to a
108
               fake mpeg frame rate in case of low frame rate */
109
            fps = frame_rate_tab[s->frame_rate_index];
110
            time_code = (INT64)s->fake_picture_number * FRAME_RATE_BASE;
111
            s->gop_picture_number = s->fake_picture_number;
112
            put_bits(&s->pb, 5, (UINT32)((time_code / (fps * 3600)) % 24));
113
            put_bits(&s->pb, 6, (UINT32)((time_code / (fps * 60)) % 60));
114
            put_bits(&s->pb, 1, 1);
115
            put_bits(&s->pb, 6, (UINT32)((time_code / fps) % 60));
116
            put_bits(&s->pb, 6, (UINT32)((time_code % fps) / FRAME_RATE_BASE));
117
            put_bits(&s->pb, 1, 1); /* closed gop */
118
            put_bits(&s->pb, 1, 0); /* broken link */
119
        }
120

    
121
        if (s->frame_rate < (24 * FRAME_RATE_BASE) && s->picture_number > 0) {
122
            /* insert empty P pictures to slow down to the desired
123
               frame rate. Each fake pictures takes about 20 bytes */
124
            fps = frame_rate_tab[s->frame_rate_index];
125
            n = (((INT64)s->picture_number * fps) / s->frame_rate) - 1;
126
            while (s->fake_picture_number < n) {
127
                mpeg1_skip_picture(s, s->fake_picture_number - 
128
                                   s->gop_picture_number); 
129
                s->fake_picture_number++;
130
            }
131

    
132
        }
133
}
134

    
135

    
136
/* insert a fake P picture */
137
static void mpeg1_skip_picture(MpegEncContext *s, int pict_num)
138
{
139
    unsigned int mb_incr;
140

    
141
    /* mpeg1 picture header */
142
    put_header(s, PICTURE_START_CODE);
143
    /* temporal reference */
144
    put_bits(&s->pb, 10, pict_num & 0x3ff); 
145
    
146
    put_bits(&s->pb, 3, P_TYPE);
147
    put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
148
    
149
    put_bits(&s->pb, 1, 1); /* integer coordinates */
150
    put_bits(&s->pb, 3, 1); /* forward_f_code */
151
    
152
    put_bits(&s->pb, 1, 0); /* extra bit picture */
153
    
154
    /* only one slice */
155
    put_header(s, SLICE_MIN_START_CODE);
156
    put_bits(&s->pb, 5, 1); /* quantizer scale */
157
    put_bits(&s->pb, 1, 0); /* slice extra information */
158
    
159
    mb_incr = 1;
160
    put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
161
             mbAddrIncrTable[mb_incr - 1][0]);
162
    
163
    /* empty macroblock */
164
    put_bits(&s->pb, 3, 1); /* motion only */
165
    
166
    /* zero motion x & y */
167
    put_bits(&s->pb, 1, 1); 
168
    put_bits(&s->pb, 1, 1); 
169

    
170
    /* output a number of empty slice */
171
    mb_incr = s->mb_width * s->mb_height - 1;
172
    while (mb_incr > 33) {
173
        put_bits(&s->pb, 11, 0x008);
174
        mb_incr -= 33;
175
    }
176
    put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
177
             mbAddrIncrTable[mb_incr - 1][0]);
178
    
179
    /* empty macroblock */
180
    put_bits(&s->pb, 3, 1); /* motion only */
181
    
182
    /* zero motion x & y */
183
    put_bits(&s->pb, 1, 1); 
184
    put_bits(&s->pb, 1, 1); 
185
}
186

    
187
void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)
188
{
189
    static int done=0;
190

    
191
    if (!done) {
192
        int i;
193
        done = 1;
194
        init_rl(&rl_mpeg1);
195
        
196
        for(i=0; i<64; i++)
197
        {
198
                mpeg1_max_level[0][i]= rl_mpeg1.max_level[0][i];
199
                mpeg1_index_run[0][i]= rl_mpeg1.index_run[0][i];
200
        }
201

    
202
        /* build unified dc encoding tables */
203
        for(i=-255; i<256; i++)
204
        {
205
                int adiff, index;
206
                int bits, code;
207
                int diff=i;
208

    
209
                adiff = ABS(diff);
210
                if(diff<0) diff--;
211
                index = vlc_dc_table[adiff];
212

    
213
                bits= vlc_dc_lum_bits[index] + index;
214
                code= (vlc_dc_lum_code[index]<<index) + (diff & ((1 << index) - 1));
215
                mpeg1_lum_dc_uni[i+255]= bits + (code<<8);
216
                
217
                bits= vlc_dc_chroma_bits[index] + index;
218
                code= (vlc_dc_chroma_code[index]<<index) + (diff & ((1 << index) - 1));
219
                mpeg1_chr_dc_uni[i+255]= bits + (code<<8);
220
        }
221
    }
222
    mpeg1_encode_sequence_header(s);
223

    
224
    /* mpeg1 picture header */
225
    put_header(s, PICTURE_START_CODE);
226
    /* temporal reference */
227
    put_bits(&s->pb, 10, (s->fake_picture_number - 
228
                          s->gop_picture_number) & 0x3ff); 
229
    s->fake_picture_number++;
230
    
231
    put_bits(&s->pb, 3, s->pict_type);
232
    put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
233
    
234
    if (s->pict_type == P_TYPE) {
235
        put_bits(&s->pb, 1, 0); /* half pel coordinates */
236
        put_bits(&s->pb, 3, s->f_code); /* forward_f_code */
237
    }
238
    
239
    put_bits(&s->pb, 1, 0); /* extra bit picture */
240
    
241
    /* only one slice */
242
    put_header(s, SLICE_MIN_START_CODE);
243
    put_bits(&s->pb, 5, s->qscale); /* quantizer scale */
244
    put_bits(&s->pb, 1, 0); /* slice extra information */
245
}
246

    
247
void mpeg1_encode_mb(MpegEncContext *s,
248
                     DCTELEM block[6][64],
249
                     int motion_x, int motion_y)
250
{
251
    int mb_incr, i, cbp, mb_x, mb_y;
252

    
253
    mb_x = s->mb_x;
254
    mb_y = s->mb_y;
255

    
256
    /* compute cbp */
257
    cbp = 0;
258
    for(i=0;i<6;i++) {
259
        if (s->block_last_index[i] >= 0)
260
            cbp |= 1 << (5 - i);
261
    }
262

    
263
    /* skip macroblock, except if first or last macroblock of a slice */
264
    if ((cbp | motion_x | motion_y) == 0 &&
265
        (!((mb_x | mb_y) == 0 ||
266
           (mb_x == s->mb_width - 1 && mb_y == s->mb_height - 1)))) {
267
        s->mb_incr++;
268
    } else {
269
        /* output mb incr */
270
        mb_incr = s->mb_incr;
271

    
272
        while (mb_incr > 33) {
273
            put_bits(&s->pb, 11, 0x008);
274
            mb_incr -= 33;
275
        }
276
        put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
277
                 mbAddrIncrTable[mb_incr - 1][0]);
278
        
279
        if (s->pict_type == I_TYPE) {
280
            put_bits(&s->pb, 1, 1); /* macroblock_type : macroblock_quant = 0 */
281
        } else {
282
            if (s->mb_intra) {
283
                put_bits(&s->pb, 5, 0x03);
284
            } else {
285
                if (cbp != 0) {
286
                    if (motion_x == 0 && motion_y == 0) {
287
                        put_bits(&s->pb, 2, 1); /* macroblock_pattern only */
288
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
289
                    } else {
290
                        put_bits(&s->pb, 1, 1); /* motion + cbp */
291
                        mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); 
292
                        mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); 
293
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
294
                    }
295
                } else {
296
                    put_bits(&s->pb, 3, 1); /* motion only */
297
                    mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); 
298
                    mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); 
299
                }
300
            }
301
        }
302
        for(i=0;i<6;i++) {
303
            if (cbp & (1 << (5 - i))) {
304
                mpeg1_encode_block(s, block[i], i);
305
            }
306
        }
307
        s->mb_incr = 1;
308
    }
309
    s->last_mv[0][0][0] = motion_x;
310
    s->last_mv[0][0][1] = motion_y;
311
}
312

    
313
static void mpeg1_encode_motion(MpegEncContext *s, int val)
314
{
315
    int code, bit_size, l, m, bits, range, sign;
316

    
317
    if (val == 0) {
318
        /* zero vector */
319
        code = 0;
320
        put_bits(&s->pb,
321
                 mbMotionVectorTable[0][1], 
322
                 mbMotionVectorTable[0][0]); 
323
    } else {
324
        bit_size = s->f_code - 1;
325
        range = 1 << bit_size;
326
        /* modulo encoding */
327
        l = 16 * range;
328
        m = 2 * l;
329
        if (val < -l) {
330
            val += m;
331
        } else if (val >= l) {
332
            val -= m;
333
        }
334

    
335
        if (val >= 0) {
336
            val--;
337
            code = (val >> bit_size) + 1;
338
            bits = val & (range - 1);
339
            sign = 0;
340
        } else {
341
            val = -val;
342
            val--;
343
            code = (val >> bit_size) + 1;
344
            bits = val & (range - 1);
345
            sign = 1;
346
        }
347
        put_bits(&s->pb,
348
                 mbMotionVectorTable[code][1], 
349
                 mbMotionVectorTable[code][0]); 
350
        put_bits(&s->pb, 1, sign);
351
        if (bit_size > 0) {
352
            put_bits(&s->pb, bit_size, bits);
353
        }
354
    }
355
}
356

    
357
void mpeg1_encode_init(MpegEncContext *s)
358
{
359
    static int done=0;
360
    if(!done){
361
        int f_code;
362
        int mv;
363

    
364
        done=1;
365
        for(f_code=1; f_code<=MAX_FCODE; f_code++){
366
            for(mv=-MAX_MV; mv<=MAX_MV; mv++){
367
                int len;
368

    
369
                if(mv==0) len= mbMotionVectorTable[0][1];
370
                else{
371
                    int val, bit_size, range, code;
372

    
373
                    bit_size = s->f_code - 1;
374
                    range = 1 << bit_size;
375

    
376
                    val=mv;
377
                    if (val < 0) 
378
                        val = -val;
379
                    val--;
380
                    code = (val >> bit_size) + 1;
381
                    if(code<17){
382
                        len= mbMotionVectorTable[code][1] + 1 + bit_size;
383
                    }else{
384
                        len= mbMotionVectorTable[16][1] + 2 + bit_size;
385
                    }
386
                }
387

    
388
                mv_penalty[f_code][mv+MAX_MV]= len;
389
            }
390
        }
391
        
392

    
393
        for(f_code=MAX_FCODE; f_code>0; f_code--){
394
            for(mv=-(8<<f_code); mv<(8<<f_code); mv++){
395
                fcode_tab[mv+MAX_MV]= f_code;
396
            }
397
        }
398
    }
399
    s->mv_penalty= mv_penalty;
400
    s->fcode_tab= fcode_tab;
401
    s->min_qcoeff=-255;
402
    s->max_qcoeff= 255;
403
    s->intra_quant_bias= 3<<(QUANT_BIAS_SHIFT-3); //(a + x*3/8)/x
404
    s->inter_quant_bias= 0;
405
}
406
 
407
static inline void encode_dc(MpegEncContext *s, int diff, int component)
408
{
409
    if (component == 0) {
410
        put_bits(
411
            &s->pb, 
412
            mpeg1_lum_dc_uni[diff+255]&0xFF,
413
            mpeg1_lum_dc_uni[diff+255]>>8);
414
    } else {
415
        put_bits(
416
            &s->pb, 
417
            mpeg1_chr_dc_uni[diff+255]&0xFF,
418
            mpeg1_chr_dc_uni[diff+255]>>8);
419
    }
420
}
421

    
422
static void mpeg1_encode_block(MpegEncContext *s, 
423
                               DCTELEM *block, 
424
                               int n)
425
{
426
    int alevel, level, last_non_zero, dc, diff, i, j, run, last_index, sign;
427
    int code, component;
428
//    RLTable *rl = &rl_mpeg1;
429

    
430
    last_index = s->block_last_index[n];
431

    
432
    /* DC coef */
433
    if (s->mb_intra) {
434
        component = (n <= 3 ? 0 : n - 4 + 1);
435
        dc = block[0]; /* overflow is impossible */
436
        diff = dc - s->last_dc[component];
437
        encode_dc(s, diff, component);
438
        s->last_dc[component] = dc;
439
        i = 1;
440
    } else {
441
        /* encode the first coefficient : needs to be done here because
442
           it is handled slightly differently */
443
        level = block[0];
444
        if (abs(level) == 1) {
445
                code = ((UINT32)level >> 31); /* the sign bit */
446
                put_bits(&s->pb, 2, code | 0x02);
447
                i = 1;
448
        } else {
449
            i = 0;
450
            last_non_zero = -1;
451
            goto next_coef;
452
        }
453
    }
454

    
455
    /* now quantify & encode AC coefs */
456
    last_non_zero = i - 1;
457

    
458
    for(;i<=last_index;i++) {
459
        j = zigzag_direct[i];
460
        level = block[j];
461
    next_coef:
462
#if 0
463
        if (level != 0)
464
            dprintf("level[%d]=%d\n", i, level);
465
#endif            
466
        /* encode using VLC */
467
        if (level != 0) {
468
            run = i - last_non_zero - 1;
469
#ifdef ARCH_X86
470
            asm volatile(
471
                "movl %2, %1                \n\t"
472
                "movl %1, %0                \n\t"
473
                "addl %1, %1                \n\t"
474
                "sbbl %1, %1                \n\t"
475
                "xorl %1, %0                \n\t"
476
                "subl %1, %0                \n\t"
477
                "andl $1, %1                \n\t"
478
                : "=&r" (alevel), "=&r" (sign)
479
                : "g" (level)
480
            );
481
#else
482
            sign = 0;
483
            alevel = level;
484
            if (alevel < 0) {
485
                sign = 1;
486
                alevel = -alevel;
487
            }
488
#endif
489
//            code = get_rl_index(rl, 0, run, alevel);
490
            if (alevel > mpeg1_max_level[0][run])
491
                code= 111; /*rl->n*/
492
            else
493
                code= mpeg1_index_run[0][run] + alevel - 1;
494

    
495
            if (code < 111 /* rl->n */) {
496
                    /* store the vlc & sign at once */
497
                put_bits(&s->pb, mpeg1_vlc[code][1]+1, (mpeg1_vlc[code][0]<<1) + sign);
498
            } else {
499
                /* escape seems to be pretty rare <5% so i dont optimize it */
500
                put_bits(&s->pb, mpeg1_vlc[111/*rl->n*/][1], mpeg1_vlc[111/*rl->n*/][0]);
501
                /* escape: only clip in this case */
502
                put_bits(&s->pb, 6, run);
503
                if (alevel < 128) {
504
                    put_bits(&s->pb, 8, level & 0xff);
505
                } else {
506
                    if (level < 0) {
507
                        put_bits(&s->pb, 16, 0x8001 + level + 255);
508
                    } else {
509
                        put_bits(&s->pb, 16, level & 0xffff);
510
                    }
511
                }
512
            }
513
            last_non_zero = i;
514
        }
515
    }
516
    /* end of block */
517
    put_bits(&s->pb, 2, 0x2);
518
}
519

    
520
/******************************************/
521
/* decoding */
522

    
523
static VLC dc_lum_vlc;
524
static VLC dc_chroma_vlc;
525
static VLC mv_vlc;
526
static VLC mbincr_vlc;
527
static VLC mb_ptype_vlc;
528
static VLC mb_btype_vlc;
529
static VLC mb_pat_vlc;
530

    
531
void mpeg1_init_vlc(MpegEncContext *s)
532
{
533
    static int done = 0;
534

    
535
    if (!done) {
536

    
537
        init_vlc(&dc_lum_vlc, 9, 12, 
538
                 vlc_dc_lum_bits, 1, 1,
539
                 vlc_dc_lum_code, 2, 2);
540
        init_vlc(&dc_chroma_vlc, 9, 12, 
541
                 vlc_dc_chroma_bits, 1, 1,
542
                 vlc_dc_chroma_code, 2, 2);
543
        init_vlc(&mv_vlc, 9, 17, 
544
                 &mbMotionVectorTable[0][1], 2, 1,
545
                 &mbMotionVectorTable[0][0], 2, 1);
546
        init_vlc(&mbincr_vlc, 9, 35, 
547
                 &mbAddrIncrTable[0][1], 2, 1,
548
                 &mbAddrIncrTable[0][0], 2, 1);
549
        init_vlc(&mb_pat_vlc, 9, 63, 
550
                 &mbPatTable[0][1], 2, 1,
551
                 &mbPatTable[0][0], 2, 1);
552
        
553
        init_vlc(&mb_ptype_vlc, 6, 32, 
554
                 &table_mb_ptype[0][1], 2, 1,
555
                 &table_mb_ptype[0][0], 2, 1);
556
        init_vlc(&mb_btype_vlc, 6, 32, 
557
                 &table_mb_btype[0][1], 2, 1,
558
                 &table_mb_btype[0][0], 2, 1);
559
        init_rl(&rl_mpeg1);
560
        init_rl(&rl_mpeg2);
561
        /* cannot use generic init because we must add the EOB code */
562
        init_vlc(&rl_mpeg1.vlc, 9, rl_mpeg1.n + 2, 
563
                 &rl_mpeg1.table_vlc[0][1], 4, 2,
564
                 &rl_mpeg1.table_vlc[0][0], 4, 2);
565
        init_vlc(&rl_mpeg2.vlc, 9, rl_mpeg2.n + 2, 
566
                 &rl_mpeg2.table_vlc[0][1], 4, 2,
567
                 &rl_mpeg2.table_vlc[0][0], 4, 2);
568
    }
569
}
570

    
571
static inline int get_dmv(MpegEncContext *s)
572
{
573
    if(get_bits1(&s->gb)) 
574
        return 1 - (get_bits1(&s->gb) << 1);
575
    else
576
        return 0;
577
}
578

    
579
static inline int get_qscale(MpegEncContext *s)
580
{
581
    int qscale;
582
    if (s->mpeg2) {
583
        if (s->q_scale_type) {
584
            qscale = non_linear_qscale[get_bits(&s->gb, 5)];
585
        } else {
586
            qscale = get_bits(&s->gb, 5) << 1;
587
        }
588
    } else {
589
        /* for mpeg1, we use the generic unquant code */
590
        qscale = get_bits(&s->gb, 5);
591
    }
592
    return qscale;
593
}
594

    
595
/* motion type (for mpeg2) */
596
#define MT_FIELD 1
597
#define MT_FRAME 2
598
#define MT_16X8  2
599
#define MT_DMV   3
600

    
601
static int mpeg_decode_mb(MpegEncContext *s,
602
                          DCTELEM block[6][64])
603
{
604
    int i, j, k, cbp, val, code, mb_type, motion_type;
605
    
606
    /* skip mb handling */
607
    if (s->mb_incr == 0) {
608
        /* read again increment */
609
        s->mb_incr = 1;
610
        for(;;) {
611
            code = get_vlc(&s->gb, &mbincr_vlc);
612
            if (code < 0)
613
                return 1; /* error = end of slice */
614
            if (code >= 33) {
615
                if (code == 33) {
616
                    s->mb_incr += 33;
617
                }
618
                /* otherwise, stuffing, nothing to do */
619
            } else {
620
                s->mb_incr += code;
621
                break;
622
            }
623
        }
624
    }
625
    if (++s->mb_x >= s->mb_width) {
626
        s->mb_x = 0;
627
        if (s->mb_y >= (s->mb_height - 1))
628
            return -1;
629
        s->mb_y++;
630
    }
631
    dprintf("decode_mb: x=%d y=%d\n", s->mb_x, s->mb_y);
632

    
633
    if (--s->mb_incr != 0) {
634
        /* skip mb */
635
        s->mb_intra = 0;
636
        for(i=0;i<6;i++)
637
            s->block_last_index[i] = -1;
638
        s->mv_type = MV_TYPE_16X16;
639
        if (s->pict_type == P_TYPE) {
640
            /* if P type, zero motion vector is implied */
641
            s->mv_dir = MV_DIR_FORWARD;
642
            s->mv[0][0][0] = s->mv[0][0][1] = 0;
643
            s->last_mv[0][0][0] = s->last_mv[0][0][1] = 0;
644
            s->last_mv[0][1][0] = s->last_mv[0][1][1] = 0;
645
        } else {
646
            /* if B type, reuse previous vectors and directions */
647
            s->mv[0][0][0] = s->last_mv[0][0][0];
648
            s->mv[0][0][1] = s->last_mv[0][0][1];
649
            s->mv[1][0][0] = s->last_mv[1][0][0];
650
            s->mv[1][0][1] = s->last_mv[1][0][1];
651
        }
652
        s->mb_skiped = 1;
653
        return 0;
654
    }
655

    
656
    switch(s->pict_type) {
657
    default:
658
    case I_TYPE:
659
        if (get_bits1(&s->gb) == 0) {
660
            if (get_bits1(&s->gb) == 0)
661
                return -1;
662
            mb_type = MB_QUANT | MB_INTRA;
663
        } else {
664
            mb_type = MB_INTRA;
665
        }
666
        break;
667
    case P_TYPE:
668
        mb_type = get_vlc(&s->gb, &mb_ptype_vlc);
669
        if (mb_type < 0)
670
            return -1;
671
        break;
672
    case B_TYPE:
673
        mb_type = get_vlc(&s->gb, &mb_btype_vlc);
674
        if (mb_type < 0)
675
            return -1;
676
        break;
677
    }
678
    dprintf("mb_type=%x\n", mb_type);
679
    motion_type = 0; /* avoid warning */
680
    if (mb_type & (MB_FOR|MB_BACK)) {
681
        /* get additionnal motion vector type */
682
        if (s->picture_structure == PICT_FRAME && s->frame_pred_frame_dct) 
683
            motion_type = MT_FRAME;
684
        else
685
            motion_type = get_bits(&s->gb, 2);
686
    }
687
    /* compute dct type */
688
    if (s->picture_structure == PICT_FRAME && 
689
        !s->frame_pred_frame_dct &&
690
        (mb_type & (MB_PAT | MB_INTRA))) {
691
        s->interlaced_dct = get_bits1(&s->gb);
692
#ifdef DEBUG
693
        if (s->interlaced_dct)
694
            printf("interlaced_dct\n");
695
#endif
696
    } else {
697
        s->interlaced_dct = 0; /* frame based */
698
    }
699

    
700
    if (mb_type & MB_QUANT) {
701
        s->qscale = get_qscale(s);
702
    }
703
    if (mb_type & MB_INTRA) {
704
        if (s->concealment_motion_vectors) {
705
            /* just parse them */
706
            if (s->picture_structure != PICT_FRAME) 
707
                skip_bits1(&s->gb); /* field select */
708
            mpeg_decode_motion(s, s->mpeg_f_code[0][0], 0);
709
            mpeg_decode_motion(s, s->mpeg_f_code[0][1], 0);
710
        }
711
        s->mb_intra = 1;
712
        cbp = 0x3f;
713
        memset(s->last_mv, 0, sizeof(s->last_mv)); /* reset mv prediction */
714
    } else {
715
        s->mb_intra = 0;
716
        cbp = 0;
717
    }
718
    /* special case of implicit zero motion vector */
719
    if (s->pict_type == P_TYPE && !(mb_type & MB_FOR)) {
720
        s->mv_dir = MV_DIR_FORWARD;
721
        s->mv_type = MV_TYPE_16X16;
722
        s->last_mv[0][0][0] = 0;
723
        s->last_mv[0][0][1] = 0;
724
        s->last_mv[0][1][0] = 0;
725
        s->last_mv[0][1][1] = 0;
726
        s->mv[0][0][0] = 0;
727
        s->mv[0][0][1] = 0;
728
    } else if (mb_type & (MB_FOR | MB_BACK)) {
729
        /* motion vectors */
730
        s->mv_dir = 0;
731
        for(i=0;i<2;i++) {
732
            if (mb_type & (MB_FOR >> i)) {
733
                s->mv_dir |= (MV_DIR_FORWARD >> i);
734
                dprintf("motion_type=%d\n", motion_type);
735
                switch(motion_type) {
736
                case MT_FRAME: /* or MT_16X8 */
737
                    if (s->picture_structure == PICT_FRAME) {
738
                        /* MT_FRAME */
739
                        s->mv_type = MV_TYPE_16X16;
740
                        for(k=0;k<2;k++) {
741
                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][k], 
742
                                                     s->last_mv[i][0][k]);
743
                            s->last_mv[i][0][k] = val;
744
                            s->last_mv[i][1][k] = val;
745
                            /* full_pel: only for mpeg1 */
746
                            if (s->full_pel[i])
747
                                val = val << 1;
748
                            s->mv[i][0][k] = val;
749
                            dprintf("mv%d: %d\n", k, val);
750
                        }
751
                    } else {
752
                        /* MT_16X8 */
753
                        s->mv_type = MV_TYPE_16X8;
754
                        for(j=0;j<2;j++) {
755
                            s->field_select[i][j] = get_bits1(&s->gb);
756
                            for(k=0;k<2;k++) {
757
                                val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
758
                                                         s->last_mv[i][j][k]);
759
                                s->last_mv[i][j][k] = val;
760
                                s->mv[i][j][k] = val;
761
                            }
762
                        }
763
                    }
764
                    break;
765
                case MT_FIELD:
766
                    if (s->picture_structure == PICT_FRAME) {
767
                        s->mv_type = MV_TYPE_FIELD;
768
                        for(j=0;j<2;j++) {
769
                            s->field_select[i][j] = get_bits1(&s->gb);
770
                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
771
                                                     s->last_mv[i][j][0]);
772
                            s->last_mv[i][j][0] = val;
773
                            s->mv[i][j][0] = val;
774
                            dprintf("fmx=%d\n", val);
775
                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
776
                                                     s->last_mv[i][j][1] >> 1);
777
                            s->last_mv[i][j][1] = val << 1;
778
                            s->mv[i][j][1] = val;
779
                            dprintf("fmy=%d\n", val);
780
                        }
781
                    } else {
782
                        s->mv_type = MV_TYPE_16X16;
783
                        s->field_select[i][0] = get_bits1(&s->gb);
784
                        for(k=0;k<2;k++) {
785
                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
786
                                                     s->last_mv[i][0][k]);
787
                            s->last_mv[i][0][k] = val;
788
                            s->last_mv[i][1][k] = val;
789
                            s->mv[i][0][k] = val;
790
                        }
791
                    }
792
                    break;
793
                case MT_DMV:
794
                    {
795
                        int dmx, dmy, mx, my, m;
796

    
797
                        mx = mpeg_decode_motion(s, s->mpeg_f_code[i][0], 
798
                                                s->last_mv[i][0][0]);
799
                        s->last_mv[i][0][0] = mx;
800
                        s->last_mv[i][1][0] = mx;
801
                        dmx = get_dmv(s);
802
                        my = mpeg_decode_motion(s, s->mpeg_f_code[i][1], 
803
                                                s->last_mv[i][0][1] >> 1);
804
                        dmy = get_dmv(s);
805
                        s->mv_type = MV_TYPE_DMV;
806
                        /* XXX: totally broken */
807
                        if (s->picture_structure == PICT_FRAME) {
808
                            s->last_mv[i][0][1] = my << 1;
809
                            s->last_mv[i][1][1] = my << 1;
810

    
811
                            m = s->top_field_first ? 1 : 3;
812
                            /* top -> top pred */
813
                            s->mv[i][0][0] = mx; 
814
                            s->mv[i][0][1] = my << 1;
815
                            s->mv[i][1][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
816
                            s->mv[i][1][1] = ((my * m + (my > 0)) >> 1) + dmy - 1;
817
                            m = 4 - m;
818
                            s->mv[i][2][0] = mx;
819
                            s->mv[i][2][1] = my << 1;
820
                            s->mv[i][3][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
821
                            s->mv[i][3][1] = ((my * m + (my > 0)) >> 1) + dmy + 1;
822
                        } else {
823
                            s->last_mv[i][0][1] = my;
824
                            s->last_mv[i][1][1] = my;
825
                            s->mv[i][0][0] = mx;
826
                            s->mv[i][0][1] = my;
827
                            s->mv[i][1][0] = ((mx + (mx > 0)) >> 1) + dmx;
828
                            s->mv[i][1][1] = ((my + (my > 0)) >> 1) + dmy - 1 
829
                                /* + 2 * cur_field */;
830
                        }
831
                    }
832
                    break;
833
                }
834
            }
835
        }
836
    }
837

    
838
    if ((mb_type & MB_INTRA) && s->concealment_motion_vectors) {
839
        skip_bits1(&s->gb); /* marker */
840
    }
841
    
842
    if (mb_type & MB_PAT) {
843
        cbp = get_vlc(&s->gb, &mb_pat_vlc);
844
        if (cbp < 0)
845
            return -1;
846
        cbp++;
847
    }
848
    dprintf("cbp=%x\n", cbp);
849

    
850
    if (s->mpeg2) {
851
        if (s->mb_intra) {
852
            for(i=0;i<6;i++) {
853
                if (cbp & (1 << (5 - i))) {
854
                    if (mpeg2_decode_block_intra(s, block[i], i) < 0)
855
                        return -1;
856
                } else {
857
                    s->block_last_index[i] = -1;
858
                }
859
            }
860
        } else {
861
            for(i=0;i<6;i++) {
862
                if (cbp & (1 << (5 - i))) {
863
                    if (mpeg2_decode_block_non_intra(s, block[i], i) < 0)
864
                        return -1;
865
                } else {
866
                    s->block_last_index[i] = -1;
867
                }
868
            }
869
        }
870
    } else {
871
        for(i=0;i<6;i++) {
872
            if (cbp & (1 << (5 - i))) {
873
                if (mpeg1_decode_block(s, block[i], i) < 0)
874
                    return -1;
875
            } else {
876
                s->block_last_index[i] = -1;
877
            }
878
        }
879
    }
880
    return 0;
881
}
882

    
883
/* as h263, but only 17 codes */
884
static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)
885
{
886
    int code, sign, val, m, l, shift;
887

    
888
    code = get_vlc(&s->gb, &mv_vlc);
889
    if (code < 0) {
890
        return 0xffff;
891
    }
892
    if (code == 0) {
893
        return pred;
894
    }
895
    sign = get_bits1(&s->gb);
896
    shift = fcode - 1;
897
    val = (code - 1) << shift;
898
    if (shift > 0)
899
        val |= get_bits(&s->gb, shift);
900
    val++;
901
    if (sign)
902
        val = -val;
903
    val += pred;
904
    
905
    /* modulo decoding */
906
    l = (1 << shift) * 16;
907
    m = 2 * l;
908
    if (val < -l) {
909
        val += m;
910
    } else if (val >= l) {
911
        val -= m;
912
    }
913
    return val;
914
}
915

    
916
static inline int decode_dc(MpegEncContext *s, int component)
917
{
918
    int code, diff;
919

    
920
    if (component == 0) {
921
        code = get_vlc(&s->gb, &dc_lum_vlc);
922
    } else {
923
        code = get_vlc(&s->gb, &dc_chroma_vlc);
924
    }
925
    if (code < 0)
926
        return 0xffff;
927
    if (code == 0) {
928
        diff = 0;
929
    } else {
930
        diff = get_bits(&s->gb, code);
931
        if ((diff & (1 << (code - 1))) == 0) 
932
            diff = (-1 << code) | (diff + 1);
933
    }
934
    return diff;
935
}
936

    
937
static int mpeg1_decode_block(MpegEncContext *s, 
938
                               DCTELEM *block, 
939
                               int n)
940
{
941
    int level, dc, diff, i, j, run;
942
    int code, component;
943
    RLTable *rl = &rl_mpeg1;
944

    
945
    if (s->mb_intra) {
946
        /* DC coef */
947
        component = (n <= 3 ? 0 : n - 4 + 1);
948
        diff = decode_dc(s, component);
949
        if (diff >= 0xffff)
950
            return -1;
951
        dc = s->last_dc[component];
952
        dc += diff;
953
        s->last_dc[component] = dc;
954
        block[0] = dc;
955
        dprintf("dc=%d diff=%d\n", dc, diff);
956
        i = 1;
957
    } else {
958
        int bit_cnt, v;
959
        UINT32 bit_buf;
960
        UINT8 *buf_ptr;
961
        i = 0;
962
        /* special case for the first coef. no need to add a second vlc table */
963
        SAVE_BITS(&s->gb);
964
        SHOW_BITS(&s->gb, v, 2);
965
        if (v & 2) {
966
            run = 0;
967
            level = 1 - ((v & 1) << 1);
968
            FLUSH_BITS(2);
969
            RESTORE_BITS(&s->gb);
970
            goto add_coef;
971
        }
972
        RESTORE_BITS(&s->gb);
973
    }
974

    
975
    /* now quantify & encode AC coefs */
976
    for(;;) {
977
        code = get_vlc(&s->gb, &rl->vlc);
978
        if (code < 0) {
979
            return -1;
980
        }
981
        if (code == 112) {
982
            break;
983
        } else if (code == 111) {
984
            /* escape */
985
            run = get_bits(&s->gb, 6);
986
            level = get_bits(&s->gb, 8);
987
            level = (level << 24) >> 24;
988
            if (level == -128) {
989
                level = get_bits(&s->gb, 8) - 256;
990
            } else if (level == 0) {
991
                level = get_bits(&s->gb, 8);
992
            }
993
        } else {
994
            run = rl->table_run[code];
995
            level = rl->table_level[code];
996
            if (get_bits1(&s->gb))
997
                level = -level;
998
        }
999
        i += run;
1000
        if (i >= 64)
1001
            return -1;
1002
    add_coef:
1003
        dprintf("%d: run=%d level=%d\n", n, run, level);
1004
        j = zigzag_direct[i];
1005
        block[j] = level;
1006
        i++;
1007
    }
1008
    s->block_last_index[n] = i-1;
1009
    return 0;
1010
}
1011

    
1012
/* Also does unquantization here, since I will never support mpeg2
1013
   encoding */
1014
static int mpeg2_decode_block_non_intra(MpegEncContext *s, 
1015
                                        DCTELEM *block, 
1016
                                        int n)
1017
{
1018
    int level, i, j, run;
1019
    int code;
1020
    RLTable *rl = &rl_mpeg1;
1021
    const UINT8 *scan_table;
1022
    const UINT16 *matrix;
1023
    int mismatch;
1024

    
1025
    if (s->alternate_scan)
1026
        scan_table = ff_alternate_vertical_scan;
1027
    else
1028
        scan_table = zigzag_direct;
1029
    mismatch = 1;
1030

    
1031
    {
1032
        int bit_cnt, v;
1033
        UINT32 bit_buf;
1034
        UINT8 *buf_ptr;
1035
        i = 0;
1036
        if (n < 4) 
1037
            matrix = s->inter_matrix;
1038
        else
1039
            matrix = s->chroma_inter_matrix;
1040
            
1041
        /* special case for the first coef. no need to add a second vlc table */
1042
        SAVE_BITS(&s->gb);
1043
        SHOW_BITS(&s->gb, v, 2);
1044
        if (v & 2) {
1045
            run = 0;
1046
            level = 1 - ((v & 1) << 1);
1047
            FLUSH_BITS(2);
1048
            RESTORE_BITS(&s->gb);
1049
            goto add_coef;
1050
        }
1051
        RESTORE_BITS(&s->gb);
1052
    }
1053

    
1054
    /* now quantify & encode AC coefs */
1055
    for(;;) {
1056
        code = get_vlc(&s->gb, &rl->vlc);
1057
        if (code < 0)
1058
            return -1;
1059
        if (code == 112) {
1060
            break;
1061
        } else if (code == 111) {
1062
            /* escape */
1063
            run = get_bits(&s->gb, 6);
1064
            level = get_bits(&s->gb, 12);
1065
            level = (level << 20) >> 20;
1066
        } else {
1067
            run = rl->table_run[code];
1068
            level = rl->table_level[code];
1069
            if (get_bits1(&s->gb))
1070
                level = -level;
1071
        }
1072
        i += run;
1073
        if (i >= 64)
1074
            return -1;
1075
    add_coef:
1076
        j = scan_table[i];
1077
        dprintf("%d: run=%d level=%d\n", n, run, level);
1078
        /* XXX: optimize */
1079
        if (level > 0) {
1080
            level = ((level * 2 + 1) * s->qscale * matrix[j]) >> 5;
1081
        } else {
1082
            level = ((-level * 2 + 1) * s->qscale * matrix[j]) >> 5;
1083
            level = -level;
1084
        }
1085
        /* XXX: is it really necessary to saturate since the encoder
1086
           knows whats going on ? */
1087
        mismatch ^= level;
1088
        block[j] = level;
1089
        i++;
1090
    }
1091
    block[63] ^= (mismatch & 1);
1092
    s->block_last_index[n] = i;
1093
    return 0;
1094
}
1095

    
1096
static int mpeg2_decode_block_intra(MpegEncContext *s, 
1097
                                    DCTELEM *block, 
1098
                                    int n)
1099
{
1100
    int level, dc, diff, i, j, run;
1101
    int code, component;
1102
    RLTable *rl;
1103
    const UINT8 *scan_table;
1104
    const UINT16 *matrix;
1105
    int mismatch;
1106

    
1107
    if (s->alternate_scan)
1108
        scan_table = ff_alternate_vertical_scan;
1109
    else
1110
        scan_table = zigzag_direct;
1111

    
1112
    /* DC coef */
1113
    component = (n <= 3 ? 0 : n - 4 + 1);
1114
    diff = decode_dc(s, component);
1115
    if (diff >= 0xffff)
1116
        return -1;
1117
    dc = s->last_dc[component];
1118
    dc += diff;
1119
    s->last_dc[component] = dc;
1120
    block[0] = dc << (3 - s->intra_dc_precision);
1121
    dprintf("dc=%d\n", block[0]);
1122
    mismatch = block[0] ^ 1;
1123
    i = 1;
1124
    if (s->intra_vlc_format)
1125
        rl = &rl_mpeg2;
1126
    else
1127
        rl = &rl_mpeg1;
1128
    if (n < 4) 
1129
        matrix = s->intra_matrix;
1130
    else
1131
        matrix = s->chroma_intra_matrix;
1132

    
1133
    /* now quantify & encode AC coefs */
1134
    for(;;) {
1135
        code = get_vlc(&s->gb, &rl->vlc);
1136
        if (code < 0)
1137
            return -1;
1138
        if (code == 112) {
1139
            break;
1140
        } else if (code == 111) {
1141
            /* escape */
1142
            run = get_bits(&s->gb, 6);
1143
            level = get_bits(&s->gb, 12);
1144
            level = (level << 20) >> 20;
1145
        } else {
1146
            run = rl->table_run[code];
1147
            level = rl->table_level[code];
1148
            if (get_bits1(&s->gb))
1149
                level = -level;
1150
        }
1151
        i += run;
1152
        if (i >= 64)
1153
            return -1;
1154
        j = scan_table[i];
1155
        dprintf("%d: run=%d level=%d\n", n, run, level);
1156
        level = (level * s->qscale * matrix[j]) / 16;
1157
        /* XXX: is it really necessary to saturate since the encoder
1158
           knows whats going on ? */
1159
        mismatch ^= level;
1160
        block[j] = level;
1161
        i++;
1162
    }
1163
    block[63] ^= (mismatch & 1);
1164
    s->block_last_index[n] = i;
1165
    return 0;
1166
}
1167

    
1168
/* compressed picture size */
1169
#define PICTURE_BUFFER_SIZE 100000
1170

    
1171
typedef struct Mpeg1Context {
1172
    MpegEncContext mpeg_enc_ctx;
1173
    UINT32 header_state;
1174
    int start_code; /* current start code */
1175
    UINT8 buffer[PICTURE_BUFFER_SIZE]; 
1176
    UINT8 *buf_ptr;
1177
    int buffer_size;
1178
    int mpeg_enc_ctx_allocated; /* true if decoding context allocated */
1179
    int repeat_field; /* true if we must repeat the field */
1180
} Mpeg1Context;
1181

    
1182
static int mpeg_decode_init(AVCodecContext *avctx)
1183
{
1184
    Mpeg1Context *s = avctx->priv_data;
1185

    
1186
    s->header_state = 0xff;
1187
    s->mpeg_enc_ctx_allocated = 0;
1188
    s->buffer_size = PICTURE_BUFFER_SIZE;
1189
    s->start_code = -1;
1190
    s->buf_ptr = s->buffer;
1191
    s->mpeg_enc_ctx.picture_number = 0;
1192
    s->repeat_field = 0;
1193
    s->mpeg_enc_ctx.codec_id= avctx->codec->id;
1194
    avctx->mbskip_table= s->mpeg_enc_ctx.mbskip_table;
1195
    s->mpeg_enc_ctx.flags= avctx->flags;
1196
    return 0;
1197
}
1198

    
1199
/* return the 8 bit start code value and update the search
1200
   state. Return -1 if no start code found */
1201
static int find_start_code(UINT8 **pbuf_ptr, UINT8 *buf_end, 
1202
                           UINT32 *header_state)
1203
{
1204
    UINT8 *buf_ptr;
1205
    unsigned int state, v;
1206
    int val;
1207

    
1208
    state = *header_state;
1209
    buf_ptr = *pbuf_ptr;
1210
    while (buf_ptr < buf_end) {
1211
        v = *buf_ptr++;
1212
        if (state == 0x000001) {
1213
            state = ((state << 8) | v) & 0xffffff;
1214
            val = state;
1215
            goto found;
1216
        }
1217
        state = ((state << 8) | v) & 0xffffff;
1218
    }
1219
    val = -1;
1220
 found:
1221
    *pbuf_ptr = buf_ptr;
1222
    *header_state = state;
1223
    return val;
1224
}
1225

    
1226
static int mpeg1_decode_picture(AVCodecContext *avctx, 
1227
                                UINT8 *buf, int buf_size)
1228
{
1229
    Mpeg1Context *s1 = avctx->priv_data;
1230
    MpegEncContext *s = &s1->mpeg_enc_ctx;
1231
    int ref, f_code;
1232

    
1233
    init_get_bits(&s->gb, buf, buf_size);
1234

    
1235
    ref = get_bits(&s->gb, 10); /* temporal ref */
1236
    s->pict_type = get_bits(&s->gb, 3);
1237
    dprintf("pict_type=%d number=%d\n", s->pict_type, s->picture_number);
1238
    skip_bits(&s->gb, 16);
1239
    if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {
1240
        s->full_pel[0] = get_bits1(&s->gb);
1241
        f_code = get_bits(&s->gb, 3);
1242
        if (f_code == 0)
1243
            return -1;
1244
        s->mpeg_f_code[0][0] = f_code;
1245
        s->mpeg_f_code[0][1] = f_code;
1246
    }
1247
    if (s->pict_type == B_TYPE) {
1248
        s->full_pel[1] = get_bits1(&s->gb);
1249
        f_code = get_bits(&s->gb, 3);
1250
        if (f_code == 0)
1251
            return -1;
1252
        s->mpeg_f_code[1][0] = f_code;
1253
        s->mpeg_f_code[1][1] = f_code;
1254
    }
1255
    s->y_dc_scale = 8;
1256
    s->c_dc_scale = 8;
1257
    s->first_slice = 1;
1258
    return 0;
1259
}
1260

    
1261
static void mpeg_decode_sequence_extension(MpegEncContext *s)
1262
{
1263
    int horiz_size_ext, vert_size_ext;
1264
    int bit_rate_ext, vbv_buf_ext, low_delay;
1265
    int frame_rate_ext_n, frame_rate_ext_d;
1266

    
1267
    skip_bits(&s->gb, 8); /* profil and level */
1268
    s->progressive_sequence = get_bits1(&s->gb); /* progressive_sequence */
1269
    skip_bits(&s->gb, 2); /* chroma_format */
1270
    horiz_size_ext = get_bits(&s->gb, 2);
1271
    vert_size_ext = get_bits(&s->gb, 2);
1272
    s->width |= (horiz_size_ext << 12);
1273
    s->height |= (vert_size_ext << 12);
1274
    bit_rate_ext = get_bits(&s->gb, 12);  /* XXX: handle it */
1275
    s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;
1276
    skip_bits1(&s->gb); /* marker */
1277
    vbv_buf_ext = get_bits(&s->gb, 8);
1278
    low_delay = get_bits1(&s->gb);
1279
    frame_rate_ext_n = get_bits(&s->gb, 2);
1280
    frame_rate_ext_d = get_bits(&s->gb, 5);
1281
    if (frame_rate_ext_d >= 1)
1282
        s->frame_rate = (s->frame_rate * frame_rate_ext_n) / frame_rate_ext_d;
1283
    dprintf("sequence extension\n");
1284
    s->mpeg2 = 1;
1285
    s->avctx->sub_id = 2; /* indicates mpeg2 found */
1286
}
1287

    
1288
static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)
1289
{
1290
    int i, v, j;
1291

    
1292
    dprintf("matrix extension\n");
1293

    
1294
    if (get_bits1(&s->gb)) {
1295
        for(i=0;i<64;i++) {
1296
            v = get_bits(&s->gb, 8);
1297
            j = zigzag_direct[i];
1298
            s->intra_matrix[j] = v;
1299
            s->chroma_intra_matrix[j] = v;
1300
        }
1301
    }
1302
    if (get_bits1(&s->gb)) {
1303
        for(i=0;i<64;i++) {
1304
            v = get_bits(&s->gb, 8);
1305
            j = zigzag_direct[i];
1306
            s->inter_matrix[j] = v;
1307
            s->chroma_inter_matrix[j] = v;
1308
        }
1309
    }
1310
    if (get_bits1(&s->gb)) {
1311
        for(i=0;i<64;i++) {
1312
            v = get_bits(&s->gb, 8);
1313
            j = zigzag_direct[i];
1314
            s->chroma_intra_matrix[j] = v;
1315
        }
1316
    }
1317
    if (get_bits1(&s->gb)) {
1318
        for(i=0;i<64;i++) {
1319
            v = get_bits(&s->gb, 8);
1320
            j = zigzag_direct[i];
1321
            s->chroma_inter_matrix[j] = v;
1322
        }
1323
    }
1324
}
1325

    
1326
static void mpeg_decode_picture_coding_extension(MpegEncContext *s)
1327
{
1328
    s->full_pel[0] = s->full_pel[1] = 0;
1329
    s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);
1330
    s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);
1331
    s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);
1332
    s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);
1333
    s->intra_dc_precision = get_bits(&s->gb, 2);
1334
    s->picture_structure = get_bits(&s->gb, 2);
1335
    s->top_field_first = get_bits1(&s->gb);
1336
    s->frame_pred_frame_dct = get_bits1(&s->gb);
1337
    s->concealment_motion_vectors = get_bits1(&s->gb);
1338
    s->q_scale_type = get_bits1(&s->gb);
1339
    s->intra_vlc_format = get_bits1(&s->gb);
1340
    s->alternate_scan = get_bits1(&s->gb);
1341
    s->repeat_first_field = get_bits1(&s->gb);
1342
    s->chroma_420_type = get_bits1(&s->gb);
1343
    s->progressive_frame = get_bits1(&s->gb);
1344
    /* composite display not parsed */
1345
    dprintf("intra_dc_precision=%d\n", s->intra_dc_precision);
1346
    dprintf("picture_structure=%d\n", s->picture_structure);
1347
    dprintf("top field first=%d\n", s->top_field_first);
1348
    dprintf("repeat first field=%d\n", s->repeat_first_field);
1349
    dprintf("conceal=%d\n", s->concealment_motion_vectors);
1350
    dprintf("intra_vlc_format=%d\n", s->intra_vlc_format);
1351
    dprintf("alternate_scan=%d\n", s->alternate_scan);
1352
    dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);
1353
    dprintf("progressive_frame=%d\n", s->progressive_frame);
1354
}
1355

    
1356
static void mpeg_decode_extension(AVCodecContext *avctx, 
1357
                                  UINT8 *buf, int buf_size)
1358
{
1359
    Mpeg1Context *s1 = avctx->priv_data;
1360
    MpegEncContext *s = &s1->mpeg_enc_ctx;
1361
    int ext_type;
1362

    
1363
    init_get_bits(&s->gb, buf, buf_size);
1364
    
1365
    ext_type = get_bits(&s->gb, 4);
1366
    switch(ext_type) {
1367
    case 0x1:
1368
        /* sequence ext */
1369
        mpeg_decode_sequence_extension(s);
1370
        break;
1371
    case 0x3:
1372
        /* quant matrix extension */
1373
        mpeg_decode_quant_matrix_extension(s);
1374
        break;
1375
    case 0x8:
1376
        /* picture extension */
1377
        mpeg_decode_picture_coding_extension(s);
1378
        break;
1379
    }
1380
}
1381

    
1382
/* return 1 if end of frame */
1383
static int mpeg_decode_slice(AVCodecContext *avctx, 
1384
                              AVPicture *pict,
1385
                              int start_code,
1386
                              UINT8 *buf, int buf_size)
1387
{
1388
    Mpeg1Context *s1 = avctx->priv_data;
1389
    MpegEncContext *s = &s1->mpeg_enc_ctx;
1390
    int ret;
1391

    
1392
    start_code = (start_code - 1) & 0xff;
1393
    if (start_code >= s->mb_height)
1394
        return -1;
1395
    s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
1396
    s->last_dc[1] = s->last_dc[0];
1397
    s->last_dc[2] = s->last_dc[0];
1398
    memset(s->last_mv, 0, sizeof(s->last_mv));
1399
    s->mb_x = -1;
1400
    s->mb_y = start_code;
1401
    s->mb_incr = 0;
1402
    /* start frame decoding */
1403
    if (s->first_slice) {
1404
        s->first_slice = 0;
1405
        MPV_frame_start(s);
1406
    }
1407

    
1408
    init_get_bits(&s->gb, buf, buf_size);
1409

    
1410
    s->qscale = get_qscale(s);
1411
    /* extra slice info */
1412
    while (get_bits1(&s->gb) != 0) {
1413
        skip_bits(&s->gb, 8);
1414
    }
1415

    
1416
    for(;;) {
1417
        clear_blocks(s->block[0]);
1418
        emms_c();
1419
        ret = mpeg_decode_mb(s, s->block);
1420
        dprintf("ret=%d\n", ret);
1421
        if (ret < 0)
1422
            return -1;
1423
        if (ret == 1)
1424
            break;
1425
        MPV_decode_mb(s, s->block);
1426
    }
1427
    emms_c();
1428

    
1429
    /* end of slice reached */
1430
    if (s->mb_x == (s->mb_width - 1) &&
1431
        s->mb_y == (s->mb_height - 1)) {
1432
        /* end of image */
1433
        UINT8 **picture;
1434

    
1435
        MPV_frame_end(s);
1436

    
1437
        /* XXX: incorrect reported qscale for mpeg2 */
1438
        if (s->pict_type == B_TYPE) {
1439
            picture = s->current_picture;
1440
            avctx->quality = s->qscale;
1441
        } else {
1442
            /* latency of 1 frame for I and P frames */
1443
            /* XXX: use another variable than picture_number */
1444
            if (s->picture_number == 0) {
1445
                picture = NULL;
1446
            } else {
1447
                picture = s->last_picture;
1448
                avctx->quality = s->last_qscale;
1449
            }
1450
            s->last_qscale = s->qscale;
1451
            s->picture_number++;
1452
        }
1453
        if (picture) {
1454
            pict->data[0] = picture[0];
1455
            pict->data[1] = picture[1];
1456
            pict->data[2] = picture[2];
1457
            pict->linesize[0] = s->linesize;
1458
            pict->linesize[1] = s->linesize / 2;
1459
            pict->linesize[2] = s->linesize / 2;
1460
            return 1;
1461
        } else {
1462
            return 0;
1463
        }
1464
    } else {
1465
        return 0;
1466
    }
1467
}
1468

    
1469
static int mpeg1_decode_sequence(AVCodecContext *avctx, 
1470
                                 UINT8 *buf, int buf_size)
1471
{
1472
    Mpeg1Context *s1 = avctx->priv_data;
1473
    MpegEncContext *s = &s1->mpeg_enc_ctx;
1474
    int width, height, i, v, j;
1475

    
1476
    init_get_bits(&s->gb, buf, buf_size);
1477

    
1478
    width = get_bits(&s->gb, 12);
1479
    height = get_bits(&s->gb, 12);
1480
    skip_bits(&s->gb, 4);
1481
    s->frame_rate_index = get_bits(&s->gb, 4);
1482
    if (s->frame_rate_index == 0)
1483
        return -1;
1484
    s->bit_rate = get_bits(&s->gb, 18) * 400;
1485
    if (get_bits1(&s->gb) == 0) /* marker */
1486
        return -1;
1487
    if (width <= 0 || height <= 0 ||
1488
        (width % 2) != 0 || (height % 2) != 0)
1489
        return -1;
1490
    if (width != s->width ||
1491
        height != s->height) {
1492
        /* start new mpeg1 context decoding */
1493
        s->out_format = FMT_MPEG1;
1494
        if (s1->mpeg_enc_ctx_allocated) {
1495
            MPV_common_end(s);
1496
        }
1497
        s->width = width;
1498
        s->height = height;
1499
        s->has_b_frames = 1;
1500
        s->avctx = avctx;
1501
        avctx->width = width;
1502
        avctx->height = height;
1503
        if (s->frame_rate_index >= 9) {
1504
            /* at least give a valid frame rate (some old mpeg1 have this) */
1505
            avctx->frame_rate = 25 * FRAME_RATE_BASE;
1506
        } else {
1507
            avctx->frame_rate = frame_rate_tab[s->frame_rate_index];
1508
        }
1509
        s->frame_rate = avctx->frame_rate;
1510
        avctx->bit_rate = s->bit_rate;
1511
        
1512
        if (MPV_common_init(s) < 0)
1513
            return -1;
1514
        mpeg1_init_vlc(s);
1515
        s1->mpeg_enc_ctx_allocated = 1;
1516
    }
1517

    
1518
    skip_bits(&s->gb, 10); /* vbv_buffer_size */
1519
    skip_bits(&s->gb, 1);
1520

    
1521
    /* get matrix */
1522
    if (get_bits1(&s->gb)) {
1523
        for(i=0;i<64;i++) {
1524
            v = get_bits(&s->gb, 8);
1525
            j = zigzag_direct[i];
1526
            s->intra_matrix[j] = v;
1527
            s->chroma_intra_matrix[j] = v;
1528
        }
1529
#ifdef DEBUG
1530
        dprintf("intra matrix present\n");
1531
        for(i=0;i<64;i++)
1532
            dprintf(" %d", s->intra_matrix[zigzag_direct[i]]);
1533
        printf("\n");
1534
#endif
1535
    } else {
1536
        for(i=0;i<64;i++) {
1537
            v = default_intra_matrix[i];
1538
            s->intra_matrix[i] = v;
1539
            s->chroma_intra_matrix[i] = v;
1540
        }
1541
    }
1542
    if (get_bits1(&s->gb)) {
1543
        for(i=0;i<64;i++) {
1544
            v = get_bits(&s->gb, 8);
1545
            j = zigzag_direct[i];
1546
            s->inter_matrix[j] = v;
1547
            s->chroma_inter_matrix[j] = v;
1548
        }
1549
#ifdef DEBUG
1550
        dprintf("non intra matrix present\n");
1551
        for(i=0;i<64;i++)
1552
            dprintf(" %d", s->inter_matrix[zigzag_direct[i]]);
1553
        printf("\n");
1554
#endif
1555
    } else {
1556
        for(i=0;i<64;i++) {
1557
            v = default_non_intra_matrix[i];
1558
            s->inter_matrix[i] = v;
1559
            s->chroma_inter_matrix[i] = v;
1560
        }
1561
    }
1562

    
1563
    /* we set mpeg2 parameters so that it emulates mpeg1 */
1564
    s->progressive_sequence = 1;
1565
    s->progressive_frame = 1;
1566
    s->picture_structure = PICT_FRAME;
1567
    s->frame_pred_frame_dct = 1;
1568
    s->mpeg2 = 0;
1569
    avctx->sub_id = 1; /* indicates mpeg1 */
1570
    return 0;
1571
}
1572

    
1573
/* handle buffering and image synchronisation */
1574
static int mpeg_decode_frame(AVCodecContext *avctx, 
1575
                             void *data, int *data_size,
1576
                             UINT8 *buf, int buf_size)
1577
{
1578
    Mpeg1Context *s = avctx->priv_data;
1579
    UINT8 *buf_end, *buf_ptr, *buf_start;
1580
    int len, start_code_found, ret, code, start_code, input_size;
1581
    AVPicture *picture = data;
1582
    MpegEncContext *s2 = &s->mpeg_enc_ctx;
1583
            
1584
    dprintf("fill_buffer\n");
1585

    
1586
    *data_size = 0;
1587

    
1588
    /* special case for last picture */
1589
    if (buf_size == 0) {
1590
        if (s2->picture_number > 0) {
1591
            picture->data[0] = s2->next_picture[0];
1592
            picture->data[1] = s2->next_picture[1];
1593
            picture->data[2] = s2->next_picture[2];
1594
            picture->linesize[0] = s2->linesize;
1595
            picture->linesize[1] = s2->linesize / 2;
1596
            picture->linesize[2] = s2->linesize / 2;
1597
            *data_size = sizeof(AVPicture);
1598
        }
1599
        return 0;
1600
    }
1601

    
1602
    buf_ptr = buf;
1603
    buf_end = buf + buf_size;
1604

    
1605
#if 0    
1606
    if (s->repeat_field % 2 == 1) { 
1607
        s->repeat_field++;
1608
        //fprintf(stderr,"\nRepeating last frame: %d -> %d! pict: %d %d", avctx->frame_number-1, avctx->frame_number,
1609
        //        s2->picture_number, s->repeat_field);
1610
        if (avctx->flags & CODEC_FLAG_REPEAT_FIELD) {
1611
            *data_size = sizeof(AVPicture);
1612
            goto the_end;
1613
        }
1614
    }
1615
#endif
1616
    while (buf_ptr < buf_end) {
1617
        buf_start = buf_ptr;
1618
        /* find start next code */
1619
        code = find_start_code(&buf_ptr, buf_end, &s->header_state);
1620
        if (code >= 0) {
1621
            start_code_found = 1;
1622
        } else {
1623
            start_code_found = 0;
1624
        }
1625
        /* copy to buffer */
1626
        len = buf_ptr - buf_start;
1627
        if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {
1628
            /* data too big : flush */
1629
            s->buf_ptr = s->buffer;
1630
            if (start_code_found)
1631
                s->start_code = code;
1632
        } else {
1633
            memcpy(s->buf_ptr, buf_start, len);
1634
            s->buf_ptr += len;
1635
            
1636
            if (start_code_found) {
1637
                /* prepare data for next start code */
1638
                input_size = s->buf_ptr - s->buffer;
1639
                start_code = s->start_code;
1640
                s->buf_ptr = s->buffer;
1641
                s->start_code = code;
1642
                switch(start_code) {
1643
                case SEQ_START_CODE:
1644
                    mpeg1_decode_sequence(avctx, s->buffer, 
1645
                                          input_size);
1646
                    break;
1647
                            
1648
                case PICTURE_START_CODE:
1649
                    /* we have a complete image : we try to decompress it */
1650
                    mpeg1_decode_picture(avctx, 
1651
                                         s->buffer, input_size);
1652
                    break;
1653
                case EXT_START_CODE:
1654
                    mpeg_decode_extension(avctx,
1655
                                          s->buffer, input_size);
1656
                    break;
1657
                default:
1658
                    if (start_code >= SLICE_MIN_START_CODE &&
1659
                        start_code <= SLICE_MAX_START_CODE) {
1660
                        ret = mpeg_decode_slice(avctx, picture,
1661
                                                start_code, s->buffer, input_size);
1662
                        if (ret == 1) {
1663
                            /* got a picture: exit */
1664
                            /* first check if we must repeat the frame */
1665
                            avctx->repeat_pict = 0;
1666
#if 0
1667
                            if (s2->progressive_frame && s2->repeat_first_field) {
1668
                                //fprintf(stderr,"\nRepeat this frame: %d! pict: %d",avctx->frame_number,s2->picture_number);
1669
                                //s2->repeat_first_field = 0;
1670
                                //s2->progressive_frame = 0;
1671
                                if (++s->repeat_field > 2)
1672
                                    s->repeat_field = 0;
1673
                                avctx->repeat_pict = 1;
1674
                            }
1675
#endif                      
1676
                            if (s2->repeat_first_field) {
1677
                                if (s2->progressive_sequence) {
1678
                                    if (s2->top_field_first)
1679
                                        avctx->repeat_pict = 4;
1680
                                    else
1681
                                        avctx->repeat_pict = 2;
1682
                                } else if (s2->progressive_frame) {
1683
                                    avctx->repeat_pict = 1;
1684
                                }
1685
                            }         
1686
                            *data_size = sizeof(AVPicture);
1687
                            goto the_end;
1688
                        }
1689
                    }
1690
                    break;
1691
                }
1692
            }
1693
        }
1694
    }
1695
 the_end:
1696
    return buf_ptr - buf;
1697
}
1698

    
1699
static int mpeg_decode_end(AVCodecContext *avctx)
1700
{
1701
    Mpeg1Context *s = avctx->priv_data;
1702

    
1703
    if (s->mpeg_enc_ctx_allocated)
1704
        MPV_common_end(&s->mpeg_enc_ctx);
1705
    return 0;
1706
}
1707

    
1708
AVCodec mpeg_decoder = {
1709
    "mpegvideo",
1710
    CODEC_TYPE_VIDEO,
1711
    CODEC_ID_MPEG1VIDEO,
1712
    sizeof(Mpeg1Context),
1713
    mpeg_decode_init,
1714
    NULL,
1715
    mpeg_decode_end,
1716
    mpeg_decode_frame,
1717
};