Statistics
| Branch: | Revision:

ffmpeg / libavcodec / mpeg12.c @ b7ec19d3

History | View | Annotate | Download (47.1 KB)

1
/*
2
 * MPEG1 encoder / MPEG2 decoder
3
 * Copyright (c) 2000,2001 Gerard Lantau.
4
 *
5
 * This program is free software; you can redistribute it and/or modify
6
 * it under the terms of the GNU General Public License as published by
7
 * the Free Software Foundation; either version 2 of the License, or
8
 * (at your option) any later version.
9
 *
10
 * This program 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
13
 * GNU General Public License for more details.
14
 *
15
 * You should have received a copy of the GNU General Public License
16
 * along with this program; if not, write to the Free Software
17
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18
 */
19
#include <stdlib.h>
20
#include <stdio.h>
21
#include <string.h>
22
#include "avcodec.h"
23
#include "dsputil.h"
24
#include "mpegvideo.h"
25

    
26
#include "mpeg12data.h"
27

    
28
//#define DEBUG
29

    
30
#ifdef DEBUG
31
#define dprintf(fmt,args...) printf(fmt, ## args)
32
#else
33
#define dprintf(fmt,args...)
34
#endif
35

    
36
/* Start codes. */
37
#define SEQ_END_CODE                0x000001b7
38
#define SEQ_START_CODE                0x000001b3
39
#define GOP_START_CODE                0x000001b8
40
#define PICTURE_START_CODE        0x00000100
41
#define SLICE_MIN_START_CODE        0x00000101
42
#define SLICE_MAX_START_CODE        0x000001af
43
#define EXT_START_CODE                0x000001b5
44
#define USER_START_CODE                0x000001b2
45

    
46
static void mpeg1_encode_block(MpegEncContext *s, 
47
                         DCTELEM *block, 
48
                         int component);
49
static void mpeg1_encode_motion(MpegEncContext *s, int val);
50
static void mpeg1_skip_picture(MpegEncContext *s, int pict_num);
51
static int mpeg1_decode_block(MpegEncContext *s, 
52
                              DCTELEM *block, 
53
                              int n);
54
static int mpeg2_decode_block_non_intra(MpegEncContext *s, 
55
                                        DCTELEM *block, 
56
                                        int n);
57
static int mpeg2_decode_block_intra(MpegEncContext *s, 
58
                                    DCTELEM *block, 
59
                                    int n);
60
static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred);
61

    
62
static void put_header(MpegEncContext *s, int header)
63
{
64
    align_put_bits(&s->pb);
65
    put_bits(&s->pb, 32, header);
66
}
67

    
68
/* put sequence header if needed */
69
static void mpeg1_encode_sequence_header(MpegEncContext *s)
70
{
71
        unsigned int vbv_buffer_size;
72
        unsigned int fps, v;
73
        int n;
74
        UINT64 time_code;
75
        
76
        if ((s->picture_number % s->gop_size) == 0) {
77
            /* mpeg1 header repeated every gop */
78
            put_header(s, SEQ_START_CODE);
79
            
80
            /* search closest frame rate */
81
            {
82
                int i, dmin, d;
83
                s->frame_rate_index = 0;
84
                dmin = 0x7fffffff;
85
                for(i=1;i<9;i++) {
86
                    d = abs(s->frame_rate - frame_rate_tab[i]);
87
                    if (d < dmin) {
88
                        dmin = d;
89
                        s->frame_rate_index = i;
90
                    }
91
                }
92
            }
93
 
94
            put_bits(&s->pb, 12, s->width);
95
            put_bits(&s->pb, 12, s->height);
96
            put_bits(&s->pb, 4, 1); /* 1/1 aspect ratio */
97
            put_bits(&s->pb, 4, s->frame_rate_index);
98
            v = s->bit_rate / 400;
99
            if (v > 0x3ffff)
100
                v = 0x3ffff;
101
            put_bits(&s->pb, 18, v);
102
            put_bits(&s->pb, 1, 1); /* marker */
103
            /* vbv buffer size: slightly greater than an I frame. We add
104
               some margin just in case */
105
            vbv_buffer_size = (3 * s->I_frame_bits) / (2 * 8);
106
            put_bits(&s->pb, 10, (vbv_buffer_size + 16383) / 16384); 
107
            put_bits(&s->pb, 1, 1); /* constrained parameter flag */
108
            put_bits(&s->pb, 1, 0); /* no custom intra matrix */
109
            put_bits(&s->pb, 1, 0); /* no custom non intra matrix */
110

    
111
            put_header(s, GOP_START_CODE);
112
            put_bits(&s->pb, 1, 0); /* do drop frame */
113
            /* time code : we must convert from the real frame rate to a
114
               fake mpeg frame rate in case of low frame rate */
115
            fps = frame_rate_tab[s->frame_rate_index];
116
            time_code = s->fake_picture_number * FRAME_RATE_BASE;
117
            s->gop_picture_number = s->fake_picture_number;
118
            put_bits(&s->pb, 5, (time_code / (fps * 3600)) % 24);
119
            put_bits(&s->pb, 6, (time_code / (fps * 60)) % 60);
120
            put_bits(&s->pb, 1, 1);
121
            put_bits(&s->pb, 6, (time_code / fps) % 60);
122
            put_bits(&s->pb, 6, (time_code % fps) / FRAME_RATE_BASE);
123
            put_bits(&s->pb, 1, 1); /* closed gop */
124
            put_bits(&s->pb, 1, 0); /* broken link */
125
        }
126

    
127
        if (s->frame_rate < (24 * FRAME_RATE_BASE) && s->picture_number > 0) {
128
            /* insert empty P pictures to slow down to the desired
129
               frame rate. Each fake pictures takes about 20 bytes */
130
            fps = frame_rate_tab[s->frame_rate_index];
131
            n = ((s->picture_number * fps) / s->frame_rate) - 1;
132
            while (s->fake_picture_number < n) {
133
                mpeg1_skip_picture(s, s->fake_picture_number - 
134
                                   s->gop_picture_number); 
135
                s->fake_picture_number++;
136
            }
137

    
138
        }
139
        s->fake_picture_number++;
140
}
141

    
142

    
143
/* insert a fake P picture */
144
static void mpeg1_skip_picture(MpegEncContext *s, int pict_num)
145
{
146
    unsigned int mb_incr;
147

    
148
    /* mpeg1 picture header */
149
    put_header(s, PICTURE_START_CODE);
150
    /* temporal reference */
151
    put_bits(&s->pb, 10, pict_num & 0x3ff); 
152
    
153
    put_bits(&s->pb, 3, P_TYPE);
154
    put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
155
    
156
    put_bits(&s->pb, 1, 1); /* integer coordinates */
157
    put_bits(&s->pb, 3, 1); /* forward_f_code */
158
    
159
    put_bits(&s->pb, 1, 0); /* extra bit picture */
160
    
161
    /* only one slice */
162
    put_header(s, SLICE_MIN_START_CODE);
163
    put_bits(&s->pb, 5, 1); /* quantizer scale */
164
    put_bits(&s->pb, 1, 0); /* slice extra information */
165
    
166
    mb_incr = 1;
167
    put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
168
             mbAddrIncrTable[mb_incr - 1][0]);
169
    
170
    /* empty macroblock */
171
    put_bits(&s->pb, 3, 1); /* motion only */
172
    
173
    /* zero motion x & y */
174
    put_bits(&s->pb, 1, 1); 
175
    put_bits(&s->pb, 1, 1); 
176

    
177
    /* output a number of empty slice */
178
    mb_incr = s->mb_width * s->mb_height - 1;
179
    while (mb_incr > 33) {
180
        put_bits(&s->pb, 11, 0x008);
181
        mb_incr -= 33;
182
    }
183
    put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
184
             mbAddrIncrTable[mb_incr - 1][0]);
185
    
186
    /* empty macroblock */
187
    put_bits(&s->pb, 3, 1); /* motion only */
188
    
189
    /* zero motion x & y */
190
    put_bits(&s->pb, 1, 1); 
191
    put_bits(&s->pb, 1, 1); 
192
}
193

    
194
void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)
195
{
196
    static int done;
197

    
198
    if (!done) {
199
        done = 1;
200
        init_rl(&rl_mpeg1);
201
    }
202
    mpeg1_encode_sequence_header(s);
203

    
204
    /* mpeg1 picture header */
205
    put_header(s, PICTURE_START_CODE);
206
    /* temporal reference */
207
    put_bits(&s->pb, 10, (s->fake_picture_number - 
208
                          s->gop_picture_number) & 0x3ff); 
209
    
210
    put_bits(&s->pb, 3, s->pict_type);
211
    put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
212
    
213
    if (s->pict_type == P_TYPE) {
214
        put_bits(&s->pb, 1, 0); /* half pel coordinates */
215
        put_bits(&s->pb, 3, s->f_code); /* forward_f_code */
216
    }
217
    
218
    put_bits(&s->pb, 1, 0); /* extra bit picture */
219
    
220
    /* only one slice */
221
    put_header(s, SLICE_MIN_START_CODE);
222
    put_bits(&s->pb, 5, s->qscale); /* quantizer scale */
223
    put_bits(&s->pb, 1, 0); /* slice extra information */
224
}
225

    
226
void mpeg1_encode_mb(MpegEncContext *s,
227
                     DCTELEM block[6][64],
228
                     int motion_x, int motion_y)
229
{
230
    int mb_incr, i, cbp, mb_x, mb_y;
231

    
232
    mb_x = s->mb_x;
233
    mb_y = s->mb_y;
234

    
235
    /* compute cbp */
236
    cbp = 0;
237
    for(i=0;i<6;i++) {
238
        if (s->block_last_index[i] >= 0)
239
            cbp |= 1 << (5 - i);
240
    }
241

    
242
    /* skip macroblock, except if first or last macroblock of a slice */
243
    if ((cbp | motion_x | motion_y) == 0 &&
244
        (!((mb_x | mb_y) == 0 ||
245
           (mb_x == s->mb_width - 1 && mb_y == s->mb_height - 1)))) {
246
        s->mb_incr++;
247
    } else {
248
        /* output mb incr */
249
        mb_incr = s->mb_incr;
250

    
251
        while (mb_incr > 33) {
252
            put_bits(&s->pb, 11, 0x008);
253
            mb_incr -= 33;
254
        }
255
        put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
256
                 mbAddrIncrTable[mb_incr - 1][0]);
257
        
258
        if (s->pict_type == I_TYPE) {
259
            put_bits(&s->pb, 1, 1); /* macroblock_type : macroblock_quant = 0 */
260
        } else {
261
            if (s->mb_intra) {
262
                put_bits(&s->pb, 5, 0x03);
263
            } else {
264
                if (cbp != 0) {
265
                    if (motion_x == 0 && motion_y == 0) {
266
                        put_bits(&s->pb, 2, 1); /* macroblock_pattern only */
267
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
268
                    } else {
269
                        put_bits(&s->pb, 1, 1); /* motion + cbp */
270
                        mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); 
271
                        mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); 
272
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
273
                    }
274
                } else {
275
                    put_bits(&s->pb, 3, 1); /* motion only */
276
                    mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); 
277
                    mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); 
278
                }
279
            }
280
        }
281
        for(i=0;i<6;i++) {
282
            if (cbp & (1 << (5 - i))) {
283
                mpeg1_encode_block(s, block[i], i);
284
            }
285
        }
286
        s->mb_incr = 1;
287
    }
288
    s->last_mv[0][0][0] = motion_x;
289
    s->last_mv[0][0][1] = motion_y;
290
}
291

    
292
static void mpeg1_encode_motion(MpegEncContext *s, int val)
293
{
294
    int code, bit_size, l, m, bits, range, sign;
295

    
296
    if (val == 0) {
297
        /* zero vector */
298
        code = 0;
299
        put_bits(&s->pb,
300
                 mbMotionVectorTable[0][1], 
301
                 mbMotionVectorTable[0][0]); 
302
    } else {
303
        bit_size = s->f_code - 1;
304
        range = 1 << bit_size;
305
        /* modulo encoding */
306
        l = 16 * range;
307
        m = 2 * l;
308
        if (val < -l) {
309
            val += m;
310
        } else if (val >= l) {
311
            val -= m;
312
        }
313

    
314
        if (val >= 0) {
315
            val--;
316
            code = (val >> bit_size) + 1;
317
            bits = val & (range - 1);
318
            sign = 0;
319
        } else {
320
            val = -val;
321
            val--;
322
            code = (val >> bit_size) + 1;
323
            bits = val & (range - 1);
324
            sign = 1;
325
        }
326
        put_bits(&s->pb,
327
                 mbMotionVectorTable[code][1], 
328
                 mbMotionVectorTable[code][0]); 
329
        put_bits(&s->pb, 1, sign);
330
        if (bit_size > 0) {
331
            put_bits(&s->pb, bit_size, bits);
332
        }
333
    }
334
}
335

    
336
static inline void encode_dc(MpegEncContext *s, int diff, int component)
337
{
338
    int adiff, index;
339

    
340
    adiff = abs(diff);
341
    index = vlc_dc_table[adiff];
342
    if (component == 0) {
343
        put_bits(&s->pb, vlc_dc_lum_bits[index], vlc_dc_lum_code[index]);
344
    } else {
345
        put_bits(&s->pb, vlc_dc_chroma_bits[index], vlc_dc_chroma_code[index]);
346
    }
347
    if (diff > 0) {
348
        put_bits(&s->pb, index, (diff & ((1 << index) - 1)));
349
    } else if (diff < 0) {
350
        put_bits(&s->pb, index, ((diff - 1) & ((1 << index) - 1)));
351
    }
352
}
353

    
354
static void mpeg1_encode_block(MpegEncContext *s, 
355
                               DCTELEM *block, 
356
                               int n)
357
{
358
    int alevel, level, last_non_zero, dc, diff, i, j, run, last_index, sign;
359
    int code, component;
360
    RLTable *rl = &rl_mpeg1;
361

    
362
    last_index = s->block_last_index[n];
363

    
364
    /* DC coef */
365
    if (s->mb_intra) {
366
        component = (n <= 3 ? 0 : n - 4 + 1);
367
        dc = block[0]; /* overflow is impossible */
368
        diff = dc - s->last_dc[component];
369
        encode_dc(s, diff, component);
370
        s->last_dc[component] = dc;
371
        i = 1;
372
    } else {
373
        /* encode the first coefficient : needs to be done here because
374
           it is handled slightly differently */
375
        level = block[0];
376
        if (abs(level) == 1) {
377
                code = ((UINT32)level >> 31); /* the sign bit */
378
                put_bits(&s->pb, 2, code | 0x02);
379
                i = 1;
380
        } else {
381
            i = 0;
382
            last_non_zero = -1;
383
            goto next_coef;
384
        }
385
    }
386

    
387
    /* now quantify & encode AC coefs */
388
    last_non_zero = i - 1;
389
    for(;i<=last_index;i++) {
390
        j = zigzag_direct[i];
391
        level = block[j];
392
    next_coef:
393
#if 0
394
        if (level != 0)
395
            dprintf("level[%d]=%d\n", i, level);
396
#endif            
397
        /* encode using VLC */
398
        if (level != 0) {
399
            run = i - last_non_zero - 1;
400
            sign = 0;
401
            alevel = level;
402
            if (alevel < 0) {
403
                sign = 1;
404
                alevel = -alevel;
405
            }
406
            code = get_rl_index(rl, 0, run, alevel);
407
            put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
408
            if (code != rl->n) {
409
                put_bits(&s->pb, 1, sign);
410
            } else {
411
                /* escape: only clip in this case */
412
                put_bits(&s->pb, 6, run);
413
                if (alevel < 128) {
414
                    put_bits(&s->pb, 8, level & 0xff);
415
                } else {
416
                    if (level < 0) {
417
                        put_bits(&s->pb, 16, 0x8001 + level + 255);
418
                    } else {
419
                        put_bits(&s->pb, 16, level & 0xffff);
420
                    }
421
                }
422
            }
423
            last_non_zero = i;
424
        }
425
    }
426
    /* end of block */
427
    put_bits(&s->pb, 2, 0x2);
428
}
429

    
430
/******************************************/
431
/* decoding */
432

    
433
static VLC dc_lum_vlc;
434
static VLC dc_chroma_vlc;
435
static VLC mv_vlc;
436
static VLC mbincr_vlc;
437
static VLC mb_ptype_vlc;
438
static VLC mb_btype_vlc;
439
static VLC mb_pat_vlc;
440

    
441
void mpeg1_init_vlc(MpegEncContext *s)
442
{
443
    static int done = 0;
444

    
445
    if (!done) {
446

    
447
        init_vlc(&dc_lum_vlc, 9, 12, 
448
                 vlc_dc_lum_bits, 1, 1,
449
                 vlc_dc_lum_code, 2, 2);
450
        init_vlc(&dc_chroma_vlc, 9, 12, 
451
                 vlc_dc_chroma_bits, 1, 1,
452
                 vlc_dc_chroma_code, 2, 2);
453
        init_vlc(&mv_vlc, 9, 17, 
454
                 &mbMotionVectorTable[0][1], 2, 1,
455
                 &mbMotionVectorTable[0][0], 2, 1);
456
        init_vlc(&mbincr_vlc, 9, 34, 
457
                 &mbAddrIncrTable[0][1], 2, 1,
458
                 &mbAddrIncrTable[0][0], 2, 1);
459
        init_vlc(&mb_pat_vlc, 9, 63, 
460
                 &mbPatTable[0][1], 2, 1,
461
                 &mbPatTable[0][0], 2, 1);
462
        
463
        init_vlc(&mb_ptype_vlc, 6, 32, 
464
                 &table_mb_ptype[0][1], 2, 1,
465
                 &table_mb_ptype[0][0], 2, 1);
466
        init_vlc(&mb_btype_vlc, 6, 32, 
467
                 &table_mb_btype[0][1], 2, 1,
468
                 &table_mb_btype[0][0], 2, 1);
469
        init_rl(&rl_mpeg1);
470
        init_rl(&rl_mpeg2);
471
        /* cannot use generic init because we must add the EOB code */
472
        init_vlc(&rl_mpeg1.vlc, 9, rl_mpeg1.n + 2, 
473
                 &rl_mpeg1.table_vlc[0][1], 4, 2,
474
                 &rl_mpeg1.table_vlc[0][0], 4, 2);
475
        init_vlc(&rl_mpeg2.vlc, 9, rl_mpeg2.n + 2, 
476
                 &rl_mpeg2.table_vlc[0][1], 4, 2,
477
                 &rl_mpeg2.table_vlc[0][0], 4, 2);
478
    }
479
}
480

    
481
static inline int get_dmv(MpegEncContext *s)
482
{
483
    if(get_bits(&s->gb, 1)) 
484
        return 1 - (get_bits(&s->gb, 1) << 1);
485
    else
486
        return 0;
487
}
488

    
489
/* motion type (for mpeg2) */
490
#define MT_FIELD 1
491
#define MT_FRAME 2
492
#define MT_16X8  2
493
#define MT_DMV   3
494

    
495
static int mpeg_decode_mb(MpegEncContext *s,
496
                          DCTELEM block[6][64])
497
{
498
    int i, j, k, cbp, val, code, mb_type, motion_type;
499
    
500
    /* skip mb handling */
501
    if (s->mb_incr == 0) {
502
        /* read again increment */
503
        s->mb_incr = 1;
504
        for(;;) {
505
            code = get_vlc(&s->gb, &mbincr_vlc);
506
            if (code < 0)
507
                return 1; /* error = end of slice */
508
            if (code >= 33) {
509
                if (code == 33) {
510
                    s->mb_incr += 33;
511
                }
512
                /* otherwise, stuffing, nothing to do */
513
            } else {
514
                s->mb_incr += code;
515
                break;
516
            }
517
        }
518
    }
519
    if (++s->mb_x >= s->mb_width) {
520
        s->mb_x = 0;
521
        if (s->mb_y >= (s->mb_height - 1))
522
            return -1;
523
        s->mb_y++;
524
    }
525
    dprintf("decode_mb: x=%d y=%d\n", s->mb_x, s->mb_y);
526

    
527
    if (--s->mb_incr != 0) {
528
        /* skip mb */
529
        s->mb_intra = 0;
530
        for(i=0;i<6;i++)
531
            s->block_last_index[i] = -1;
532
        s->mv_type = MV_TYPE_16X16;
533
        if (s->pict_type == P_TYPE) {
534
            /* if P type, zero motion vector is implied */
535
            s->mv_dir = MV_DIR_FORWARD;
536
            s->mv[0][0][0] = s->mv[0][0][1] = 0;
537
            s->last_mv[0][0][0] = s->last_mv[0][0][1] = 0;
538
        } else {
539
            /* if B type, reuse previous vectors and directions */
540
            s->mv[0][0][0] = s->last_mv[0][0][0];
541
            s->mv[0][0][1] = s->last_mv[0][0][1];
542
            s->mv[1][0][0] = s->last_mv[1][0][0];
543
            s->mv[1][0][1] = s->last_mv[1][0][1];
544
        }
545
        s->mb_skiped = 1;
546
        return 0;
547
    }
548

    
549
    switch(s->pict_type) {
550
    default:
551
    case I_TYPE:
552
        if (get_bits(&s->gb, 1) == 0) {
553
            if (get_bits(&s->gb, 1) == 0)
554
                return -1;
555
            mb_type = MB_QUANT | MB_INTRA;
556
        } else {
557
            mb_type = MB_INTRA;
558
        }
559
        break;
560
    case P_TYPE:
561
        mb_type = get_vlc(&s->gb, &mb_ptype_vlc);
562
        if (mb_type < 0)
563
            return -1;
564
        break;
565
    case B_TYPE:
566
        mb_type = get_vlc(&s->gb, &mb_btype_vlc);
567
        if (mb_type < 0)
568
            return -1;
569
        break;
570
    }
571
    dprintf("mb_type=%x\n", mb_type);
572
    motion_type = 0; /* avoid warning */
573
    if (mb_type & (MB_FOR|MB_BACK)) {
574
        /* get additionnal motion vector type */
575
        if (s->picture_structure == PICT_FRAME && s->frame_pred_frame_dct) 
576
            motion_type = MT_FRAME;
577
        else
578
            motion_type = get_bits(&s->gb, 2);
579
    }
580
    /* compute dct type */
581
    if (s->picture_structure == PICT_FRAME && 
582
        !s->frame_pred_frame_dct &&
583
        (mb_type & (MB_PAT | MB_INTRA))) {
584
        s->interlaced_dct = get_bits(&s->gb, 1);
585
#ifdef DEBUG
586
        if (s->interlaced_dct)
587
            printf("interlaced_dct\n");
588
#endif
589
    } else {
590
        s->interlaced_dct = 0; /* frame based */
591
    }
592

    
593
    if (mb_type & MB_QUANT) {
594
        if (s->mpeg2) {
595
            if (s->q_scale_type) {
596
                s->qscale = non_linear_qscale[get_bits(&s->gb, 5)];
597
            } else {
598
                s->qscale = get_bits(&s->gb, 5) << 1;
599
            }
600
        } else {
601
            /* for mpeg1, we use the generic unquant code */
602
            s->qscale = get_bits(&s->gb, 5);
603
        }
604
    }
605
    if (mb_type & MB_INTRA) {
606
        if (s->concealment_motion_vectors) {
607
            /* just parse them */
608
            if (s->picture_structure != PICT_FRAME) 
609
                get_bits(&s->gb, 1); /* field select */
610
            mpeg_decode_motion(s, s->mpeg_f_code[0][0], 0);
611
            mpeg_decode_motion(s, s->mpeg_f_code[0][1], 0);
612
        }
613
        s->mb_intra = 1;
614
        cbp = 0x3f;
615
        memset(s->last_mv, 0, sizeof(s->last_mv)); /* reset mv prediction */
616
    } else {
617
        s->mb_intra = 0;
618
        cbp = 0;
619
    }
620
    /* special case of implicit zero motion vector */
621
    if (s->pict_type == P_TYPE && !(mb_type & MB_FOR)) {
622
        s->mv_dir = MV_DIR_FORWARD;
623
        s->mv_type = MV_TYPE_16X16;
624
        s->last_mv[0][0][0] = 0;
625
        s->last_mv[0][0][1] = 0;
626
        s->mv[0][0][0] = 0;
627
        s->mv[0][0][1] = 0;
628
    } else if (mb_type & (MB_FOR | MB_BACK)) {
629
        /* motion vectors */
630
        s->mv_dir = 0;
631
        for(i=0;i<2;i++) {
632
            if (mb_type & (MB_FOR >> i)) {
633
                s->mv_dir |= (MV_DIR_FORWARD >> i);
634
                dprintf("mv_type=%d\n", motion_type);
635
                switch(motion_type) {
636
                case MT_FRAME: /* or MT_16X8 */
637
                    if (s->picture_structure == PICT_FRAME) {
638
                        /* MT_FRAME */
639
                        s->mv_type = MV_TYPE_16X16;
640
                        for(k=0;k<2;k++) {
641
                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][k], 
642
                                                     s->last_mv[i][0][k]);
643
                            s->last_mv[i][0][k] = val;
644
                            s->last_mv[i][1][k] = val;
645
                            /* full_pel: only for mpeg1 */
646
                            if (s->full_pel[i])
647
                                val = val << 1;
648
                            s->mv[i][0][k] = val;
649
                            dprintf("mv%d: %d\n", k, val);
650
                        }
651
                    } else {
652
                        /* MT_16X8 */
653
                        s->mv_type = MV_TYPE_16X8;
654
                        for(j=0;j<2;j++) {
655
                            s->field_select[i][j] = get_bits(&s->gb, 1);
656
                            for(k=0;k<2;k++) {
657
                                val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
658
                                                         s->last_mv[i][j][k]);
659
                                s->last_mv[i][j][k] = val;
660
                                s->mv[i][j][k] = val;
661
                            }
662
                        }
663
                    }
664
                    break;
665
                case MT_FIELD:
666
                    if (s->picture_structure == PICT_FRAME) {
667
                        s->mv_type = MV_TYPE_FIELD;
668
                        for(j=0;j<2;j++) {
669
                            s->field_select[i][j] = get_bits(&s->gb, 1);
670
                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
671
                                                     s->last_mv[i][j][0]);
672
                            s->last_mv[i][j][0] = val;
673
                            s->mv[i][j][0] = val;
674
                            dprintf("fmx=%d\n", val);
675
                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
676
                                                     s->last_mv[i][j][1] >> 1);
677
                            s->last_mv[i][j][1] = val << 1;
678
                            s->mv[i][j][1] = val;
679
                            dprintf("fmy=%d\n", val);
680
                        }
681
                    } else {
682
                        s->mv_type = MV_TYPE_16X16;
683
                        s->field_select[i][0] = get_bits(&s->gb, 1);
684
                        for(k=0;k<2;k++) {
685
                            val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
686
                                                     s->last_mv[i][0][k]);
687
                            s->last_mv[i][0][k] = val;
688
                            s->last_mv[i][1][k] = val;
689
                            s->mv[i][0][k] = val;
690
                        }
691
                    }
692
                    break;
693
                case MT_DMV:
694
                    {
695
                        int dmx, dmy, mx, my, m;
696

    
697
                        mx = mpeg_decode_motion(s, s->mpeg_f_code[i][0], 
698
                                                s->last_mv[i][0][0]);
699
                        s->last_mv[i][0][0] = mx;
700
                        s->last_mv[i][1][0] = mx;
701
                        dmx = get_dmv(s);
702
                        my = mpeg_decode_motion(s, s->mpeg_f_code[i][1], 
703
                                                s->last_mv[i][0][1] >> 1);
704
                        dmy = get_dmv(s);
705
                        s->mv_type = MV_TYPE_DMV;
706
                        /* XXX: totally broken */
707
                        if (s->picture_structure == PICT_FRAME) {
708
                            s->last_mv[i][0][1] = my << 1;
709
                            s->last_mv[i][1][1] = my << 1;
710

    
711
                            m = s->top_field_first ? 1 : 3;
712
                            /* top -> top pred */
713
                            s->mv[i][0][0] = mx; 
714
                            s->mv[i][0][1] = my << 1;
715
                            s->mv[i][1][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
716
                            s->mv[i][1][1] = ((my * m + (my > 0)) >> 1) + dmy - 1;
717
                            m = 4 - m;
718
                            s->mv[i][2][0] = mx;
719
                            s->mv[i][2][1] = my << 1;
720
                            s->mv[i][3][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
721
                            s->mv[i][3][1] = ((my * m + (my > 0)) >> 1) + dmy + 1;
722
                        } else {
723
                            s->last_mv[i][0][1] = my;
724
                            s->last_mv[i][1][1] = my;
725
                            s->mv[i][0][0] = mx;
726
                            s->mv[i][0][1] = my;
727
                            s->mv[i][1][0] = ((mx + (mx > 0)) >> 1) + dmx;
728
                            s->mv[i][1][1] = ((my + (my > 0)) >> 1) + dmy - 1 
729
                                /* + 2 * cur_field */;
730
                        }
731
                    }
732
                    break;
733
                }
734
            }
735
        }
736
    }
737

    
738
    if ((mb_type & MB_INTRA) && s->concealment_motion_vectors) {
739
        get_bits(&s->gb, 1); /* marker */
740
    }
741
    
742
    if (mb_type & MB_PAT) {
743
        cbp = get_vlc(&s->gb, &mb_pat_vlc);
744
        if (cbp < 0)
745
            return -1;
746
        cbp++;
747
    }
748
    dprintf("cbp=%x\n", cbp);
749

    
750
    if (s->mpeg2) {
751
        if (s->mb_intra) {
752
            for(i=0;i<6;i++) {
753
                if (cbp & (1 << (5 - i))) {
754
                    if (mpeg2_decode_block_intra(s, block[i], i) < 0)
755
                        return -1;
756
                }
757
            }
758
        } else {
759
            for(i=0;i<6;i++) {
760
                if (cbp & (1 << (5 - i))) {
761
                    if (mpeg2_decode_block_non_intra(s, block[i], i) < 0)
762
                        return -1;
763
                }
764
            }
765
        }
766
    } else {
767
        for(i=0;i<6;i++) {
768
            if (cbp & (1 << (5 - i))) {
769
                if (mpeg1_decode_block(s, block[i], i) < 0)
770
                    return -1;
771
            }
772
        }
773
    }
774
    return 0;
775
}
776

    
777
/* as h263, but only 17 codes */
778
static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)
779
{
780
    int code, sign, val, m, l, shift;
781

    
782
    code = get_vlc(&s->gb, &mv_vlc);
783
    if (code < 0) {
784
        return 0xffff;
785
    }
786
    if (code == 0) {
787
        return pred;
788
    }
789
    sign = get_bits(&s->gb, 1);
790
    shift = fcode - 1;
791
    val = (code - 1) << shift;
792
    if (shift > 0)
793
        val |= get_bits(&s->gb, shift);
794
    val++;
795
    if (sign)
796
        val = -val;
797
    val += pred;
798
    
799
    /* modulo decoding */
800
    l = (1 << shift) * 16;
801
    m = 2 * l;
802
    if (val < -l) {
803
        val += m;
804
    } else if (val >= l) {
805
        val -= m;
806
    }
807
    return val;
808
}
809

    
810
static inline int decode_dc(MpegEncContext *s, int component)
811
{
812
    int code, diff;
813

    
814
    if (component == 0) {
815
        code = get_vlc(&s->gb, &dc_lum_vlc);
816
    } else {
817
        code = get_vlc(&s->gb, &dc_chroma_vlc);
818
    }
819
    if (code < 0)
820
        return 0xffff;
821
    if (code == 0) {
822
        diff = 0;
823
    } else {
824
        diff = get_bits(&s->gb, code);
825
        if ((diff & (1 << (code - 1))) == 0) 
826
            diff = (-1 << code) | (diff + 1);
827
    }
828
    return diff;
829
}
830

    
831
static int mpeg1_decode_block(MpegEncContext *s, 
832
                               DCTELEM *block, 
833
                               int n)
834
{
835
    int level, dc, diff, i, j, run;
836
    int code, component;
837
    RLTable *rl = &rl_mpeg1;
838

    
839
    if (s->mb_intra) {
840
        /* DC coef */
841
        component = (n <= 3 ? 0 : n - 4 + 1);
842
        diff = decode_dc(s, component);
843
        if (diff >= 0xffff)
844
            return -1;
845
        dc = s->last_dc[component];
846
        dc += diff;
847
        s->last_dc[component] = dc;
848
        block[0] = dc;
849
        dprintf("dc=%d diff=%d\n", dc, diff);
850
        i = 1;
851
    } else {
852
        int bit_cnt, v;
853
        UINT32 bit_buf;
854
        UINT8 *buf_ptr;
855
        i = 0;
856
        /* special case for the first coef. no need to add a second vlc table */
857
        SAVE_BITS(&s->gb);
858
        SHOW_BITS(&s->gb, v, 2);
859
        if (v & 2) {
860
            run = 0;
861
            level = 1 - ((v & 1) << 1);
862
            FLUSH_BITS(2);
863
            RESTORE_BITS(&s->gb);
864
            goto add_coef;
865
        }
866
        RESTORE_BITS(&s->gb);
867
    }
868

    
869
    /* now quantify & encode AC coefs */
870
    for(;;) {
871
        code = get_vlc(&s->gb, &rl->vlc);
872
        if (code < 0) {
873
            return -1;
874
        }
875
        if (code == 112) {
876
            break;
877
        } else if (code == 111) {
878
            /* escape */
879
            run = get_bits(&s->gb, 6);
880
            level = get_bits(&s->gb, 8);
881
            level = (level << 24) >> 24;
882
            if (level == -128) {
883
                level = get_bits(&s->gb, 8) - 256;
884
            } else if (level == 0) {
885
                level = get_bits(&s->gb, 8);
886
            }
887
        } else {
888
            run = rl->table_run[code];
889
            level = rl->table_level[code];
890
            if (get_bits(&s->gb, 1))
891
                level = -level;
892
        }
893
        i += run;
894
        if (i >= 64)
895
            return -1;
896
    add_coef:
897
        dprintf("%d: run=%d level=%d\n", n, run, level);
898
        j = zigzag_direct[i];
899
        block[j] = level;
900
        i++;
901
    }
902
    s->block_last_index[n] = i;
903
    return 0;
904
}
905

    
906
/* Also does unquantization here, since I will never support mpeg2
907
   encoding */
908
static int mpeg2_decode_block_non_intra(MpegEncContext *s, 
909
                                        DCTELEM *block, 
910
                                        int n)
911
{
912
    int level, i, j, run;
913
    int code;
914
    RLTable *rl = &rl_mpeg1;
915
    const UINT8 *scan_table;
916
    const UINT16 *matrix;
917
    int mismatch;
918

    
919
    if (s->alternate_scan)
920
        scan_table = ff_alternate_vertical_scan;
921
    else
922
        scan_table = zigzag_direct;
923
    mismatch = 1;
924

    
925
    {
926
        int bit_cnt, v;
927
        UINT32 bit_buf;
928
        UINT8 *buf_ptr;
929
        i = 0;
930
        if (n < 4) 
931
            matrix = s->non_intra_matrix;
932
        else
933
            matrix = s->chroma_non_intra_matrix;
934
            
935
        /* special case for the first coef. no need to add a second vlc table */
936
        SAVE_BITS(&s->gb);
937
        SHOW_BITS(&s->gb, v, 2);
938
        if (v & 2) {
939
            run = 0;
940
            level = 1 - ((v & 1) << 1);
941
            FLUSH_BITS(2);
942
            RESTORE_BITS(&s->gb);
943
            goto add_coef;
944
        }
945
        RESTORE_BITS(&s->gb);
946
    }
947

    
948
    /* now quantify & encode AC coefs */
949
    for(;;) {
950
        code = get_vlc(&s->gb, &rl->vlc);
951
        if (code < 0)
952
            return -1;
953
        if (code == 112) {
954
            break;
955
        } else if (code == 111) {
956
            /* escape */
957
            run = get_bits(&s->gb, 6);
958
            level = get_bits(&s->gb, 12);
959
            level = (level << 20) >> 20;
960
        } else {
961
            run = rl->table_run[code];
962
            level = rl->table_level[code];
963
            if (get_bits(&s->gb, 1))
964
                level = -level;
965
        }
966
        i += run;
967
        if (i >= 64)
968
            return -1;
969
    add_coef:
970
        j = scan_table[i];
971
        dprintf("%d: run=%d level=%d\n", n, run, level);
972
        level = ((level * 2 + 1) * s->qscale * matrix[j]) / 32;
973
        /* XXX: is it really necessary to saturate since the encoder
974
           knows whats going on ? */
975
        mismatch ^= level;
976
        block[j] = level;
977
        i++;
978
    }
979
    block[63] ^= (mismatch & 1);
980
    s->block_last_index[n] = i;
981
    return 0;
982
}
983

    
984
static int mpeg2_decode_block_intra(MpegEncContext *s, 
985
                                    DCTELEM *block, 
986
                                    int n)
987
{
988
    int level, dc, diff, i, j, run;
989
    int code, component;
990
    RLTable *rl;
991
    const UINT8 *scan_table;
992
    const UINT16 *matrix;
993
    int mismatch;
994

    
995
    if (s->alternate_scan)
996
        scan_table = ff_alternate_vertical_scan;
997
    else
998
        scan_table = zigzag_direct;
999
    mismatch = 1;
1000

    
1001
    /* DC coef */
1002
    component = (n <= 3 ? 0 : n - 4 + 1);
1003
    diff = decode_dc(s, component);
1004
    if (diff >= 0xffff)
1005
        return -1;
1006
    dc = s->last_dc[component];
1007
    dc += diff;
1008
    s->last_dc[component] = dc;
1009
    block[0] = dc << (3 - s->intra_dc_precision);
1010
    dprintf("dc=%d\n", block[0]);
1011
    i = 1;
1012
    if (s->intra_vlc_format)
1013
        rl = &rl_mpeg2;
1014
    else
1015
        rl = &rl_mpeg1;
1016
    if (n < 4) 
1017
        matrix = s->intra_matrix;
1018
    else
1019
        matrix = s->chroma_intra_matrix;
1020
        
1021
    /* now quantify & encode AC coefs */
1022
    for(;;) {
1023
        code = get_vlc(&s->gb, &rl->vlc);
1024
        if (code < 0)
1025
            return -1;
1026
        if (code == 112) {
1027
            break;
1028
        } else if (code == 111) {
1029
            /* escape */
1030
            run = get_bits(&s->gb, 6);
1031
            level = get_bits(&s->gb, 12);
1032
            level = (level << 20) >> 20;
1033
        } else {
1034
            run = rl->table_run[code];
1035
            level = rl->table_level[code];
1036
            if (get_bits(&s->gb, 1))
1037
                level = -level;
1038
        }
1039
        i += run;
1040
        if (i >= 64)
1041
            return -1;
1042
        j = scan_table[i];
1043
        dprintf("%d: run=%d level=%d\n", n, run, level);
1044
        level = (level * s->qscale * matrix[j]) / 16;
1045
        /* XXX: is it really necessary to saturate since the encoder
1046
           knows whats going on ? */
1047
        mismatch ^= level;
1048
        block[j] = level;
1049
        i++;
1050
    }
1051
    block[63] ^= (mismatch & 1);
1052
    s->block_last_index[n] = i;
1053
    return 0;
1054
}
1055

    
1056
/* compressed picture size */
1057
#define PICTURE_BUFFER_SIZE 100000
1058

    
1059
typedef struct Mpeg1Context {
1060
    MpegEncContext mpeg_enc_ctx;
1061
    UINT32 header_state;
1062
    int start_code; /* current start code */
1063
    UINT8 buffer[PICTURE_BUFFER_SIZE]; 
1064
    UINT8 *buf_ptr;
1065
    int buffer_size;
1066
    int mpeg_enc_ctx_allocated; /* true if decoding context allocated */
1067
} Mpeg1Context;
1068

    
1069
static int mpeg_decode_init(AVCodecContext *avctx)
1070
{
1071
    Mpeg1Context *s = avctx->priv_data;
1072

    
1073
    s->header_state = 0xff;
1074
    s->mpeg_enc_ctx_allocated = 0;
1075
    s->buffer_size = PICTURE_BUFFER_SIZE;
1076
    s->start_code = -1;
1077
    s->buf_ptr = s->buffer;
1078
    s->mpeg_enc_ctx.picture_number = 0;
1079
    return 0;
1080
}
1081

    
1082
/* return the 8 bit start code value and update the search
1083
   state. Return -1 if no start code found */
1084
static int find_start_code(UINT8 **pbuf_ptr, UINT8 *buf_end, 
1085
                           UINT32 *header_state)
1086
{
1087
    UINT8 *buf_ptr;
1088
    unsigned int state, v;
1089
    int val;
1090

    
1091
    state = *header_state;
1092
    buf_ptr = *pbuf_ptr;
1093
    while (buf_ptr < buf_end) {
1094
        v = *buf_ptr++;
1095
        if (state == 0x000001) {
1096
            state = ((state << 8) | v) & 0xffffff;
1097
            val = state;
1098
            goto found;
1099
        }
1100
        state = ((state << 8) | v) & 0xffffff;
1101
    }
1102
    val = -1;
1103
 found:
1104
    *pbuf_ptr = buf_ptr;
1105
    *header_state = state;
1106
    return val;
1107
}
1108

    
1109
static int mpeg1_decode_picture(AVCodecContext *avctx, 
1110
                                UINT8 *buf, int buf_size)
1111
{
1112
    Mpeg1Context *s1 = avctx->priv_data;
1113
    MpegEncContext *s = &s1->mpeg_enc_ctx;
1114
    int ref, f_code;
1115

    
1116
    init_get_bits(&s->gb, buf, buf_size);
1117

    
1118
    ref = get_bits(&s->gb, 10); /* temporal ref */
1119
    s->pict_type = get_bits(&s->gb, 3);
1120
    dprintf("pict_type=%d\n", s->pict_type);
1121
    get_bits(&s->gb, 16);
1122
    if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {
1123
        s->full_pel[0] = get_bits(&s->gb, 1);
1124
        f_code = get_bits(&s->gb, 3);
1125
        if (f_code == 0)
1126
            return -1;
1127
        s->mpeg_f_code[0][0] = f_code;
1128
        s->mpeg_f_code[0][1] = f_code;
1129
    }
1130
    if (s->pict_type == B_TYPE) {
1131
        s->full_pel[1] = get_bits(&s->gb, 1);
1132
        f_code = get_bits(&s->gb, 3);
1133
        if (f_code == 0)
1134
            return -1;
1135
        s->mpeg_f_code[1][0] = f_code;
1136
        s->mpeg_f_code[1][1] = f_code;
1137
    }
1138
    s->y_dc_scale = 8;
1139
    s->c_dc_scale = 8;
1140
    s->first_slice = 1;
1141
    return 0;
1142
}
1143

    
1144
static void mpeg_decode_sequence_extension(MpegEncContext *s)
1145
{
1146
    int horiz_size_ext, vert_size_ext;
1147
    int bit_rate_ext, vbv_buf_ext, low_delay;
1148
    int frame_rate_ext_n, frame_rate_ext_d;
1149

    
1150
    get_bits(&s->gb, 8); /* profil and level */
1151
    get_bits(&s->gb, 1); /* progressive_sequence */
1152
    get_bits(&s->gb, 2); /* chroma_format */
1153
    horiz_size_ext = get_bits(&s->gb, 2);
1154
    vert_size_ext = get_bits(&s->gb, 2);
1155
    s->width |= (horiz_size_ext << 12);
1156
    s->height |= (vert_size_ext << 12);
1157
    bit_rate_ext = get_bits(&s->gb, 12);  /* XXX: handle it */
1158
    s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;
1159
    get_bits(&s->gb, 1); /* marker */
1160
    vbv_buf_ext = get_bits(&s->gb, 8);
1161
    low_delay = get_bits(&s->gb, 1);
1162
    frame_rate_ext_n = get_bits(&s->gb, 2);
1163
    frame_rate_ext_d = get_bits(&s->gb, 5);
1164
    if (frame_rate_ext_d >= 1)
1165
        s->frame_rate = (s->frame_rate * frame_rate_ext_n) / frame_rate_ext_d;
1166
    dprintf("sequence extension\n");
1167
    s->mpeg2 = 1;
1168
}
1169

    
1170
static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)
1171
{
1172
    int i, v;
1173

    
1174
    if (get_bits(&s->gb, 1)) {
1175
        for(i=0;i<64;i++) {
1176
            v = get_bits(&s->gb, 8);
1177
            s->intra_matrix[i] = v;
1178
            s->chroma_intra_matrix[i] = v;
1179
        }
1180
    }
1181
    if (get_bits(&s->gb, 1)) {
1182
        for(i=0;i<64;i++) {
1183
            v = get_bits(&s->gb, 8);
1184
            s->non_intra_matrix[i] = v;
1185
            s->chroma_non_intra_matrix[i] = v;
1186
        }
1187
    }
1188
    if (get_bits(&s->gb, 1)) {
1189
        for(i=0;i<64;i++) {
1190
            v = get_bits(&s->gb, 8);
1191
            s->chroma_intra_matrix[i] = v;
1192
        }
1193
    }
1194
    if (get_bits(&s->gb, 1)) {
1195
        for(i=0;i<64;i++) {
1196
            v = get_bits(&s->gb, 8);
1197
            s->chroma_non_intra_matrix[i] = v;
1198
        }
1199
    }
1200
}
1201

    
1202
static void mpeg_decode_picture_coding_extension(MpegEncContext *s)
1203
{
1204
    s->full_pel[0] = s->full_pel[1] = 0;
1205
    s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);
1206
    s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);
1207
    s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);
1208
    s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);
1209
    s->intra_dc_precision = get_bits(&s->gb, 2);
1210
    s->picture_structure = get_bits(&s->gb, 2);
1211
    s->top_field_first = get_bits(&s->gb, 1);
1212
    s->frame_pred_frame_dct = get_bits(&s->gb, 1);
1213
    s->concealment_motion_vectors = get_bits(&s->gb, 1);
1214
    s->q_scale_type = get_bits(&s->gb, 1);
1215
    s->intra_vlc_format = get_bits(&s->gb, 1);
1216
    s->alternate_scan = get_bits(&s->gb, 1);
1217
    s->repeat_first_field = get_bits(&s->gb, 1);
1218
    s->chroma_420_type = get_bits(&s->gb, 1);
1219
    s->progressive_frame = get_bits(&s->gb, 1);
1220
    /* composite display not parsed */
1221
    dprintf("dc_preci=%d\n", s->intra_dc_precision);
1222
    dprintf("pict_structure=%d\n", s->picture_structure);
1223
    dprintf("conceal=%d\n", s->concealment_motion_vectors);
1224
    dprintf("intrafmt=%d\n", s->intra_vlc_format);
1225
    dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);
1226
}
1227

    
1228
static void mpeg_decode_extension(AVCodecContext *avctx, 
1229
                                  UINT8 *buf, int buf_size)
1230
{
1231
    Mpeg1Context *s1 = avctx->priv_data;
1232
    MpegEncContext *s = &s1->mpeg_enc_ctx;
1233
    int ext_type;
1234

    
1235
    init_get_bits(&s->gb, buf, buf_size);
1236
    
1237
    ext_type = get_bits(&s->gb, 4);
1238
    switch(ext_type) {
1239
    case 0x1:
1240
        /* sequence ext */
1241
        mpeg_decode_sequence_extension(s);
1242
        break;
1243
    case 0x3:
1244
        /* quant matrix extension */
1245
        mpeg_decode_quant_matrix_extension(s);
1246
        break;
1247
    case 0x8:
1248
        /* picture extension */
1249
        mpeg_decode_picture_coding_extension(s);
1250
        break;
1251
    }
1252
}
1253

    
1254
/* return 1 if end of frame */
1255
static int mpeg_decode_slice(AVCodecContext *avctx, 
1256
                              AVPicture *pict,
1257
                              int start_code,
1258
                              UINT8 *buf, int buf_size)
1259
{
1260
    Mpeg1Context *s1 = avctx->priv_data;
1261
    MpegEncContext *s = &s1->mpeg_enc_ctx;
1262
    int ret;
1263

    
1264
    start_code = (start_code - 1) & 0xff;
1265
    if (start_code >= s->mb_height)
1266
        return -1;
1267
    s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
1268
    s->last_dc[1] = s->last_dc[0];
1269
    s->last_dc[2] = s->last_dc[0];
1270
    memset(s->last_mv, 0, sizeof(s->last_mv));
1271
    s->mb_x = -1;
1272
    s->mb_y = start_code;
1273
    s->mb_incr = 0;
1274

    
1275
    /* start frame decoding */
1276
    if (s->first_slice) {
1277
        s->first_slice = 0;
1278
        MPV_frame_start(s);
1279
    }
1280

    
1281
    init_get_bits(&s->gb, buf, buf_size);
1282

    
1283
    s->qscale = get_bits(&s->gb, 5);
1284
    /* extra slice info */
1285
    while (get_bits(&s->gb, 1) != 0) {
1286
        get_bits(&s->gb, 8);
1287
    }
1288

    
1289
    for(;;) {
1290
        memset(s->block, 0, sizeof(s->block));
1291
        ret = mpeg_decode_mb(s, s->block);
1292
        dprintf("ret=%d\n", ret);
1293
        if (ret < 0)
1294
            return -1;
1295
        if (ret == 1)
1296
            break;
1297
        MPV_decode_mb(s, s->block);
1298
    }
1299
    
1300
    /* end of slice reached */
1301
    if (s->mb_x == (s->mb_width - 1) &&
1302
        s->mb_y == (s->mb_height - 1)) {
1303
        /* end of image */
1304
        UINT8 **picture;
1305

    
1306
        MPV_frame_end(s);
1307

    
1308
        /* XXX: incorrect reported qscale for mpeg2 */
1309
        if (s->pict_type == B_TYPE) {
1310
            picture = s->current_picture;
1311
            avctx->quality = s->qscale;
1312
        } else {
1313
            /* latency of 1 frame for I and P frames */
1314
            /* XXX: use another variable than picture_number */
1315
            if (s->picture_number == 0) {
1316
                picture = NULL;
1317
            } else {
1318
                picture = s->last_picture;
1319
                avctx->quality = s->last_qscale;
1320
            }
1321
            s->last_qscale = s->qscale;
1322
            s->picture_number++;
1323
        }
1324
        if (picture) {
1325
            pict->data[0] = picture[0];
1326
            pict->data[1] = picture[1];
1327
            pict->data[2] = picture[2];
1328
            pict->linesize[0] = s->linesize;
1329
            pict->linesize[1] = s->linesize / 2;
1330
            pict->linesize[2] = s->linesize / 2;
1331
            return 1;
1332
        } else {
1333
            return 0;
1334
        }
1335
    } else {
1336
        return 0;
1337
    }
1338
}
1339

    
1340
static int mpeg1_decode_sequence(AVCodecContext *avctx, 
1341
                                 UINT8 *buf, int buf_size)
1342
{
1343
    Mpeg1Context *s1 = avctx->priv_data;
1344
    MpegEncContext *s = &s1->mpeg_enc_ctx;
1345
    int width, height, i, v;
1346
    
1347
    init_get_bits(&s->gb, buf, buf_size);
1348

    
1349
    width = get_bits(&s->gb, 12);
1350
    height = get_bits(&s->gb, 12);
1351
    get_bits(&s->gb, 4);
1352
    s->frame_rate_index = get_bits(&s->gb, 4);
1353
    if (s->frame_rate_index == 0)
1354
        return -1;
1355
    s->bit_rate = get_bits(&s->gb, 18) * 400;
1356
    if (get_bits(&s->gb, 1) == 0) /* marker */
1357
        return -1;
1358
    if (width <= 0 || height <= 0 ||
1359
        (width % 2) != 0 || (height % 2) != 0)
1360
        return -1;
1361
    if (width != s->width ||
1362
        height != s->height) {
1363
        /* start new mpeg1 context decoding */
1364
        s->out_format = FMT_MPEG1;
1365
        if (s1->mpeg_enc_ctx_allocated) {
1366
            MPV_common_end(s);
1367
        }
1368
        s->width = width;
1369
        s->height = height;
1370
        s->has_b_frames = 1;
1371
        avctx->width = width;
1372
        avctx->height = height;
1373
        avctx->frame_rate = frame_rate_tab[s->frame_rate_index];
1374
        avctx->bit_rate = s->bit_rate;
1375
        
1376
        if (MPV_common_init(s) < 0)
1377
            return -1;
1378
        mpeg1_init_vlc(s);
1379
        s1->mpeg_enc_ctx_allocated = 1;
1380
    }
1381

    
1382
    get_bits(&s->gb, 10); /* vbv_buffer_size */
1383
    get_bits(&s->gb, 1);
1384

    
1385
    /* get matrix */
1386
    if (get_bits(&s->gb, 1)) {
1387
        for(i=0;i<64;i++) {
1388
            v = get_bits(&s->gb, 8);
1389
            s->intra_matrix[i] = v;
1390
            s->chroma_intra_matrix[i] = v;
1391
        }
1392
    } else {
1393
        for(i=0;i<64;i++) {
1394
            v = default_intra_matrix[i];
1395
            s->intra_matrix[i] = v;
1396
            s->chroma_intra_matrix[i] = v;
1397
        }
1398
    }
1399
    if (get_bits(&s->gb, 1)) {
1400
        for(i=0;i<64;i++) {
1401
            v = get_bits(&s->gb, 8);
1402
            s->non_intra_matrix[i] = v;
1403
            s->chroma_non_intra_matrix[i] = v;
1404
        }
1405
    } else {
1406
        for(i=0;i<64;i++) {
1407
            v = default_non_intra_matrix[i];
1408
            s->non_intra_matrix[i] = v;
1409
            s->chroma_non_intra_matrix[i] = v;
1410
        }
1411
    }
1412

    
1413
    /* we set mpeg2 parameters so that it emulates mpeg1 */
1414
    s->progressive_sequence = 1;
1415
    s->progressive_frame = 1;
1416
    s->picture_structure = PICT_FRAME;
1417
    s->frame_pred_frame_dct = 1;
1418
    s->mpeg2 = 0;
1419
    return 0;
1420
}
1421

    
1422
/* handle buffering and image synchronisation */
1423
static int mpeg_decode_frame(AVCodecContext *avctx, 
1424
                             void *data, int *data_size,
1425
                             UINT8 *buf, int buf_size)
1426
{
1427
    Mpeg1Context *s = avctx->priv_data;
1428
    UINT8 *buf_end, *buf_ptr, *buf_start;
1429
    int len, start_code_found, ret, code, start_code, input_size;
1430
    AVPicture *picture = data;
1431

    
1432
    dprintf("fill_buffer\n");
1433

    
1434
    *data_size = 0;
1435
    /* special case for last picture */
1436
    if (buf_size == 0) {
1437
        MpegEncContext *s2 = &s->mpeg_enc_ctx;
1438
        if (s2->picture_number > 0) {
1439
            picture->data[0] = s2->next_picture[0];
1440
            picture->data[1] = s2->next_picture[1];
1441
            picture->data[2] = s2->next_picture[2];
1442
            picture->linesize[0] = s2->linesize;
1443
            picture->linesize[1] = s2->linesize / 2;
1444
            picture->linesize[2] = s2->linesize / 2;
1445
            *data_size = sizeof(AVPicture);
1446
        }
1447
        return 0;
1448
    }
1449

    
1450
    buf_ptr = buf;
1451
    buf_end = buf + buf_size;
1452
    while (buf_ptr < buf_end) {
1453
        buf_start = buf_ptr;
1454
        /* find start next code */
1455
        code = find_start_code(&buf_ptr, buf_end, &s->header_state);
1456
        if (code >= 0) {
1457
            start_code_found = 1;
1458
        } else {
1459
            start_code_found = 0;
1460
        }
1461
        /* copy to buffer */
1462
        len = buf_ptr - buf_start;
1463
        if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {
1464
            /* data too big : flush */
1465
            s->buf_ptr = s->buffer;
1466
            if (start_code_found)
1467
                s->start_code = code;
1468
        } else {
1469
            memcpy(s->buf_ptr, buf_start, len);
1470
            s->buf_ptr += len;
1471
            
1472
            if (start_code_found) {
1473
                /* prepare data for next start code */
1474
                input_size = s->buf_ptr - s->buffer;
1475
                start_code = s->start_code;
1476
                s->buf_ptr = s->buffer;
1477
                s->start_code = code;
1478
                switch(start_code) {
1479
                case SEQ_START_CODE:
1480
                    mpeg1_decode_sequence(avctx, s->buffer, 
1481
                                          input_size);
1482
                    break;
1483
                            
1484
                case PICTURE_START_CODE:
1485
                    /* we have a complete image : we try to decompress it */
1486
                    mpeg1_decode_picture(avctx, 
1487
                                         s->buffer, input_size);
1488
                    break;
1489
                case EXT_START_CODE:
1490
                    mpeg_decode_extension(avctx,
1491
                                          s->buffer, input_size);
1492
                    break;
1493
                default:
1494
                    if (start_code >= SLICE_MIN_START_CODE &&
1495
                        start_code <= SLICE_MAX_START_CODE) {
1496
                        ret = mpeg_decode_slice(avctx, picture,
1497
                                                start_code, s->buffer, input_size);
1498
                        if (ret == 1) {
1499
                            /* got a picture: exit */
1500
                            *data_size = sizeof(AVPicture);
1501
                            goto the_end;
1502
                        }
1503
                    }
1504
                    break;
1505
                }
1506
            }
1507
        }
1508
    }
1509
 the_end:
1510
    return buf_ptr - buf;
1511
}
1512

    
1513
static int mpeg_decode_end(AVCodecContext *avctx)
1514
{
1515
    Mpeg1Context *s = avctx->priv_data;
1516

    
1517
    if (s->mpeg_enc_ctx_allocated)
1518
        MPV_common_end(&s->mpeg_enc_ctx);
1519
    return 0;
1520
}
1521

    
1522
AVCodec mpeg_decoder = {
1523
    "mpegvideo",
1524
    CODEC_TYPE_VIDEO,
1525
    CODEC_ID_MPEG1VIDEO,
1526
    sizeof(Mpeg1Context),
1527
    mpeg_decode_init,
1528
    NULL,
1529
    mpeg_decode_end,
1530
    mpeg_decode_frame,
1531
};