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1
/*
2
 * DV decoder
3
 * Copyright (c) 2002 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
16
 * License along with this library; if not, write to the Free Software
17
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18
 */
19
#include "avcodec.h"
20
#include "dsputil.h"
21
#include "mpegvideo.h"
22
#include "simple_idct.h"
23

    
24
#define NTSC_FRAME_SIZE 120000
25
#define PAL_FRAME_SIZE  144000
26

    
27
#define TEX_VLC_BITS 9
28

    
29
typedef struct DVVideoDecodeContext {
30
    AVCodecContext *avctx;
31
    GetBitContext gb;
32
    VLC *vlc;
33
    int sampling_411; /* 0 = 420, 1 = 411 */
34
    int width, height;
35
    uint8_t *current_picture[3]; /* picture structure */
36
    AVFrame picture;
37
    int linesize[3];
38
    DCTELEM block[5*6][64] __align8;
39
    uint8_t dv_zigzag[2][64];
40
    uint8_t idct_permutation[64];
41
    /* XXX: move it to static storage ? */
42
    uint8_t dv_shift[2][22][64];
43
    void (*idct_put[2])(uint8_t *dest, int line_size, DCTELEM *block);
44
} DVVideoDecodeContext;
45

    
46
#include "dvdata.h"
47

    
48
static VLC dv_vlc;
49
/* XXX: also include quantization */
50
static RL_VLC_ELEM *dv_rl_vlc[1];
51

    
52
static void dv_build_unquantize_tables(DVVideoDecodeContext *s)
53
{
54
    int i, q, j;
55

    
56
    /* NOTE: max left shift is 6 */
57
    for(q = 0; q < 22; q++) {
58
        /* 88 unquant */
59
        for(i = 1; i < 64; i++) {
60
            /* 88 table */
61
            j = s->idct_permutation[i];
62
            s->dv_shift[0][q][j] =
63
                dv_quant_shifts[q][dv_88_areas[i]] + 1;
64
        }
65
        
66
        /* 248 unquant */
67
        for(i = 1; i < 64; i++) {
68
            /* 248 table */
69
            s->dv_shift[1][q][i] =  
70
                    dv_quant_shifts[q][dv_248_areas[i]] + 1;
71
        }
72
    }
73
}
74

    
75
static int dvvideo_decode_init(AVCodecContext *avctx)
76
{
77
    DVVideoDecodeContext *s = avctx->priv_data;
78
    MpegEncContext s2;
79
    static int done=0;
80

    
81
    if (!done) {
82
        int i;
83

    
84
        done = 1;
85

    
86
        /* NOTE: as a trick, we use the fact the no codes are unused
87
           to accelerate the parsing of partial codes */
88
        init_vlc(&dv_vlc, TEX_VLC_BITS, NB_DV_VLC, 
89
                 dv_vlc_len, 1, 1, dv_vlc_bits, 2, 2);
90

    
91
        dv_rl_vlc[0] = av_malloc(dv_vlc.table_size * sizeof(RL_VLC_ELEM));
92
        for(i = 0; i < dv_vlc.table_size; i++){
93
            int code= dv_vlc.table[i][0];
94
            int len = dv_vlc.table[i][1];
95
            int level, run;
96
        
97
            if(len<0){ //more bits needed
98
                run= 0;
99
                level= code;
100
            } else if (code == (NB_DV_VLC - 1)) {
101
                /* EOB */
102
                run = 0;
103
                level = 256;
104
            } else {
105
                run=   dv_vlc_run[code] + 1;
106
                level= dv_vlc_level[code];
107
            }
108
            dv_rl_vlc[0][i].len = len;
109
            dv_rl_vlc[0][i].level = level;
110
            dv_rl_vlc[0][i].run = run;
111
        }
112
    }
113

    
114
    /* ugly way to get the idct & scantable */
115
    /* XXX: fix it */
116
    memset(&s2, 0, sizeof(MpegEncContext));
117
    s2.avctx = avctx;
118
    dsputil_init(&s2.dsp, avctx->dsp_mask);
119
    if (DCT_common_init(&s2) < 0)
120
       return -1;
121

    
122
    s->idct_put[0] = s2.idct_put;
123
    memcpy(s->idct_permutation, s2.idct_permutation, 64);
124
    memcpy(s->dv_zigzag[0], s2.intra_scantable.permutated, 64);
125

    
126
    /* XXX: use MMX also for idct248 */
127
    s->idct_put[1] = simple_idct248_put;
128
    memcpy(s->dv_zigzag[1], dv_248_zigzag, 64);
129

    
130
    /* XXX: do it only for constant case */
131
    dv_build_unquantize_tables(s);
132
    
133
    return 0;
134
}
135

    
136
//#define VLC_DEBUG
137

    
138
typedef struct BlockInfo {
139
    const uint8_t *shift_table;
140
    const uint8_t *scan_table;
141
    uint8_t pos; /* position in block */
142
    uint8_t eob_reached; /* true if EOB has been reached */
143
    uint8_t dct_mode;
144
    uint8_t partial_bit_count;
145
    uint16_t partial_bit_buffer;
146
    int shift_offset;
147
} BlockInfo;
148

    
149
/* block size in bits */
150
static const uint16_t block_sizes[6] = {
151
    112, 112, 112, 112, 80, 80
152
};
153

    
154
#ifndef ALT_BITSTREAM_READER
155
#error only works with ALT_BITSTREAM_READER
156
#endif
157

    
158
/* decode ac coefs */
159
static void dv_decode_ac(DVVideoDecodeContext *s, 
160
                         BlockInfo *mb, DCTELEM *block, int last_index)
161
{
162
    int last_re_index;
163
    int shift_offset = mb->shift_offset;
164
    const uint8_t *scan_table = mb->scan_table;
165
    const uint8_t *shift_table = mb->shift_table;
166
    int pos = mb->pos;
167
    int level, pos1, sign, run;
168
    int partial_bit_count;
169

    
170
    OPEN_READER(re, &s->gb);
171
    
172
#ifdef VLC_DEBUG
173
    printf("start\n");
174
#endif
175

    
176
    /* if we must parse a partial vlc, we do it here */
177
    partial_bit_count = mb->partial_bit_count;
178
    if (partial_bit_count > 0) {
179
        uint8_t buf[4];
180
        uint32_t v;
181
        int l, l1;
182
        GetBitContext gb1;
183

    
184
        /* build the dummy bit buffer */
185
        l = 16 - partial_bit_count;
186
        UPDATE_CACHE(re, &s->gb);
187
#ifdef VLC_DEBUG
188
        printf("show=%04x\n", SHOW_UBITS(re, &s->gb, 16));
189
#endif
190
        v = (mb->partial_bit_buffer << l) | SHOW_UBITS(re, &s->gb, l);
191
        buf[0] = v >> 8;
192
        buf[1] = v;
193
#ifdef VLC_DEBUG
194
        printf("v=%04x cnt=%d %04x\n", 
195
               v, partial_bit_count, (mb->partial_bit_buffer << l));
196
#endif
197
        /* try to read the codeword */
198
        init_get_bits(&gb1, buf, 4*8);
199
        {
200
            OPEN_READER(re1, &gb1);
201
            UPDATE_CACHE(re1, &gb1);
202
            GET_RL_VLC(level, run, re1, &gb1, dv_rl_vlc[0], 
203
                       TEX_VLC_BITS, 2);
204
            l = re1_index;
205
            CLOSE_READER(re1, &gb1);
206
        }
207
#ifdef VLC_DEBUG
208
        printf("****run=%d level=%d size=%d\n", run, level, l);
209
#endif
210
        /* compute codeword length */
211
        l1 = (level != 256 && level != 0);
212
        /* if too long, we cannot parse */
213
        l -= partial_bit_count;
214
        if ((re_index + l + l1) > last_index)
215
            return;
216
        /* skip read bits */
217
        last_re_index = 0; /* avoid warning */
218
        re_index += l;
219
        /* by definition, if we can read the vlc, all partial bits
220
           will be read (otherwise we could have read the vlc before) */
221
        mb->partial_bit_count = 0;
222
        UPDATE_CACHE(re, &s->gb);
223
        goto handle_vlc;
224
    }
225

    
226
    /* get the AC coefficients until last_index is reached */
227
    for(;;) {
228
        UPDATE_CACHE(re, &s->gb);
229
#ifdef VLC_DEBUG
230
        printf("%2d: bits=%04x index=%d\n", 
231
               pos, SHOW_UBITS(re, &s->gb, 16), re_index);
232
#endif
233
        last_re_index = re_index;
234
        GET_RL_VLC(level, run, re, &s->gb, dv_rl_vlc[0], 
235
                   TEX_VLC_BITS, 2);
236
    handle_vlc:
237
#ifdef VLC_DEBUG
238
        printf("run=%d level=%d\n", run, level);
239
#endif
240
        if (level == 256) {
241
            if (re_index > last_index) {
242
            cannot_read:
243
                /* put position before read code */
244
                re_index = last_re_index;
245
                mb->eob_reached = 0;
246
                break;
247
            }
248
            /* EOB */
249
            mb->eob_reached = 1;
250
            break;
251
        } else if (level != 0) {
252
            if ((re_index + 1) > last_index)
253
                goto cannot_read;
254
            sign = SHOW_SBITS(re, &s->gb, 1);
255
            level = (level ^ sign) - sign;
256
            LAST_SKIP_BITS(re, &s->gb, 1);
257
            pos += run;
258
            /* error */
259
            if (pos >= 64) {
260
                goto read_error;
261
            }
262
            pos1 = scan_table[pos];
263
            level = level << (shift_table[pos1] + shift_offset);
264
            block[pos1] = level;
265
            //            printf("run=%d level=%d shift=%d\n", run, level, shift_table[pos1]);
266
        } else {
267
            if (re_index > last_index)
268
                goto cannot_read;
269
            /* level is zero: means run without coding. No
270
               sign is coded */
271
            pos += run;
272
            /* error */
273
            if (pos >= 64) {
274
            read_error:
275
#if defined(VLC_DEBUG) || 1
276
                printf("error pos=%d\n", pos);
277
#endif
278
                /* for errors, we consider the eob is reached */
279
                mb->eob_reached = 1;
280
                break;
281
            }
282
        }
283
    }
284
    CLOSE_READER(re, &s->gb);
285
    mb->pos = pos;
286
}
287

    
288
static inline void bit_copy(PutBitContext *pb, GetBitContext *gb, int bits_left)
289
{
290
    while (bits_left >= 16) {
291
        put_bits(pb, 16, get_bits(gb, 16));
292
        bits_left -= 16;
293
    }
294
    if (bits_left > 0) {
295
        put_bits(pb, bits_left, get_bits(gb, bits_left));
296
    }
297
}
298

    
299
/* mb_x and mb_y are in units of 8 pixels */
300
static inline void dv_decode_video_segment(DVVideoDecodeContext *s, 
301
                                           uint8_t *buf_ptr1, 
302
                                           const uint16_t *mb_pos_ptr)
303
{
304
    int quant, dc, dct_mode, class1, j;
305
    int mb_index, mb_x, mb_y, v, last_index;
306
    DCTELEM *block, *block1;
307
    int c_offset, bits_left;
308
    uint8_t *y_ptr;
309
    BlockInfo mb_data[5 * 6], *mb, *mb1;
310
    void (*idct_put)(uint8_t *dest, int line_size, DCTELEM *block);
311
    uint8_t *buf_ptr;
312
    PutBitContext pb, vs_pb;
313
    uint8_t mb_bit_buffer[80 + 4]; /* allow some slack */
314
    int mb_bit_count;
315
    uint8_t vs_bit_buffer[5 * 80 + 4]; /* allow some slack */
316
    int vs_bit_count;
317
    
318
    memset(s->block, 0, sizeof(s->block));
319

    
320
    /* pass 1 : read DC and AC coefficients in blocks */
321
    buf_ptr = buf_ptr1;
322
    block1 = &s->block[0][0];
323
    mb1 = mb_data;
324
    init_put_bits(&vs_pb, vs_bit_buffer, 5 * 80, NULL, NULL);
325
    vs_bit_count = 0;
326
    for(mb_index = 0; mb_index < 5; mb_index++) {
327
        /* skip header */
328
        quant = buf_ptr[3] & 0x0f;
329
        buf_ptr += 4;
330
        init_put_bits(&pb, mb_bit_buffer, 80, NULL, NULL);
331
        mb_bit_count = 0;
332
        mb = mb1;
333
        block = block1;
334
        for(j = 0;j < 6; j++) {
335
            /* NOTE: size is not important here */
336
            init_get_bits(&s->gb, buf_ptr, 14*8);
337
            
338
            /* get the dc */
339
            dc = get_bits(&s->gb, 9);
340
            dc = (dc << (32 - 9)) >> (32 - 9);
341
            dct_mode = get_bits1(&s->gb);
342
            mb->dct_mode = dct_mode;
343
            mb->scan_table = s->dv_zigzag[dct_mode];
344
            class1 = get_bits(&s->gb, 2);
345
            mb->shift_offset = (class1 == 3);
346
            mb->shift_table = s->dv_shift[dct_mode]
347
                [quant + dv_quant_offset[class1]];
348
            dc = dc << 2;
349
            /* convert to unsigned because 128 is not added in the
350
               standard IDCT */
351
            dc += 1024;
352
            block[0] = dc;
353
            last_index = block_sizes[j];
354
            buf_ptr += last_index >> 3;
355
            mb->pos = 0;
356
            mb->partial_bit_count = 0;
357

    
358
            dv_decode_ac(s, mb, block, last_index);
359

    
360
            /* write the remaining bits  in a new buffer only if the
361
               block is finished */
362
            bits_left = last_index - s->gb.index;
363
            if (mb->eob_reached) {
364
                mb->partial_bit_count = 0;
365
                mb_bit_count += bits_left;
366
                bit_copy(&pb, &s->gb, bits_left);
367
            } else {
368
                /* should be < 16 bits otherwise a codeword could have
369
                   been parsed */
370
                mb->partial_bit_count = bits_left;
371
                mb->partial_bit_buffer = get_bits(&s->gb, bits_left);
372
            }
373
            block += 64;
374
            mb++;
375
        }
376
        
377
        flush_put_bits(&pb);
378

    
379
        /* pass 2 : we can do it just after */
380
#ifdef VLC_DEBUG
381
        printf("***pass 2 size=%d\n", mb_bit_count);
382
#endif
383
        block = block1;
384
        mb = mb1;
385
        init_get_bits(&s->gb, mb_bit_buffer, 80*8);
386
        for(j = 0;j < 6; j++) {
387
            if (!mb->eob_reached && s->gb.index < mb_bit_count) {
388
                dv_decode_ac(s, mb, block, mb_bit_count);
389
                /* if still not finished, no need to parse other blocks */
390
                if (!mb->eob_reached) {
391
                    /* we could not parse the current AC coefficient,
392
                       so we add the remaining bytes */
393
                    bits_left = mb_bit_count - s->gb.index;
394
                    if (bits_left > 0) {
395
                        mb->partial_bit_count += bits_left;
396
                        mb->partial_bit_buffer = 
397
                            (mb->partial_bit_buffer << bits_left) | 
398
                            get_bits(&s->gb, bits_left);
399
                    }
400
                    goto next_mb;
401
                }
402
            }
403
            block += 64;
404
            mb++;
405
        }
406
        /* all blocks are finished, so the extra bytes can be used at
407
           the video segment level */
408
        bits_left = mb_bit_count - s->gb.index;
409
        vs_bit_count += bits_left;
410
        bit_copy(&vs_pb, &s->gb, bits_left);
411
    next_mb:
412
        mb1 += 6;
413
        block1 += 6 * 64;
414
    }
415

    
416
    /* we need a pass other the whole video segment */
417
    flush_put_bits(&vs_pb);
418
        
419
#ifdef VLC_DEBUG
420
    printf("***pass 3 size=%d\n", vs_bit_count);
421
#endif
422
    block = &s->block[0][0];
423
    mb = mb_data;
424
    init_get_bits(&s->gb, vs_bit_buffer, 5 * 80*8);
425
    for(mb_index = 0; mb_index < 5; mb_index++) {
426
        for(j = 0;j < 6; j++) {
427
            if (!mb->eob_reached) {
428
#ifdef VLC_DEBUG
429
                printf("start %d:%d\n", mb_index, j);
430
#endif
431
                dv_decode_ac(s, mb, block, vs_bit_count);
432
            }
433
            block += 64;
434
            mb++;
435
        }
436
    }
437
    
438
    /* compute idct and place blocks */
439
    block = &s->block[0][0];
440
    mb = mb_data;
441
    for(mb_index = 0; mb_index < 5; mb_index++) {
442
        v = *mb_pos_ptr++;
443
        mb_x = v & 0xff;
444
        mb_y = v >> 8;
445
        y_ptr = s->current_picture[0] + (mb_y * s->linesize[0] * 8) + (mb_x * 8);
446
        if (s->sampling_411)
447
            c_offset = (mb_y * s->linesize[1] * 8) + ((mb_x >> 2) * 8);
448
        else
449
            c_offset = ((mb_y >> 1) * s->linesize[1] * 8) + ((mb_x >> 1) * 8);
450
        for(j = 0;j < 6; j++) {
451
            idct_put = s->idct_put[mb->dct_mode];
452
            if (j < 4) {
453
                if (s->sampling_411 && mb_x < (704 / 8)) {
454
                    /* NOTE: at end of line, the macroblock is handled as 420 */
455
                    idct_put(y_ptr + (j * 8), s->linesize[0], block);
456
                } else {
457
                    idct_put(y_ptr + ((j & 1) * 8) + ((j >> 1) * 8 * s->linesize[0]),
458
                             s->linesize[0], block);
459
                }
460
            } else {
461
                if (s->sampling_411 && mb_x >= (704 / 8)) {
462
                    uint8_t pixels[64], *c_ptr, *c_ptr1, *ptr;
463
                    int y, linesize;
464
                    /* NOTE: at end of line, the macroblock is handled as 420 */
465
                    idct_put(pixels, 8, block);
466
                    linesize = s->linesize[6 - j];
467
                    c_ptr = s->current_picture[6 - j] + c_offset;
468
                    ptr = pixels;
469
                    for(y = 0;y < 8; y++) {
470
                        /* convert to 411P */
471
                        c_ptr1 = c_ptr + linesize;
472
                        c_ptr1[0] = c_ptr[0] = (ptr[0] + ptr[1]) >> 1;
473
                        c_ptr1[1] = c_ptr[1] = (ptr[2] + ptr[3]) >> 1;
474
                        c_ptr1[2] = c_ptr[2] = (ptr[4] + ptr[5]) >> 1;
475
                        c_ptr1[3] = c_ptr[3] = (ptr[6] + ptr[7]) >> 1;
476
                        c_ptr += linesize * 2;
477
                        ptr += 8;
478
                    }
479
                } else {
480
                    /* don't ask me why they inverted Cb and Cr ! */
481
                    idct_put(s->current_picture[6 - j] + c_offset, 
482
                             s->linesize[6 - j], block);
483
                }
484
            }
485
            block += 64;
486
            mb++;
487
        }
488
    }
489
}
490

    
491

    
492
/* NOTE: exactly one frame must be given (120000 bytes for NTSC,
493
   144000 bytes for PAL) */
494
static int dvvideo_decode_frame(AVCodecContext *avctx, 
495
                                 void *data, int *data_size,
496
                                 uint8_t *buf, int buf_size)
497
{
498
    DVVideoDecodeContext *s = avctx->priv_data;
499
    int sct, dsf, apt, ds, nb_dif_segs, vs, width, height, i, packet_size;
500
    uint8_t *buf_ptr;
501
    const uint16_t *mb_pos_ptr;
502
    
503
    /* parse id */
504
    init_get_bits(&s->gb, buf, buf_size*8);
505
    sct = get_bits(&s->gb, 3);
506
    if (sct != 0)
507
        return -1;
508
    skip_bits(&s->gb, 5);
509
    get_bits(&s->gb, 4); /* dsn (sequence number */
510
    get_bits(&s->gb, 1); /* fsc (channel number) */
511
    skip_bits(&s->gb, 3);
512
    get_bits(&s->gb, 8); /* dbn (diff block number 0-134) */
513

    
514
    dsf = get_bits(&s->gb, 1); /* 0 = NTSC 1 = PAL */
515
    if (get_bits(&s->gb, 1) != 0)
516
        return -1;
517
    skip_bits(&s->gb, 11);
518
    apt = get_bits(&s->gb, 3); /* apt */
519

    
520
    get_bits(&s->gb, 1); /* tf1 */
521
    skip_bits(&s->gb, 4);
522
    get_bits(&s->gb, 3); /* ap1 */
523

    
524
    get_bits(&s->gb, 1); /* tf2 */
525
    skip_bits(&s->gb, 4);
526
    get_bits(&s->gb, 3); /* ap2 */
527

    
528
    get_bits(&s->gb, 1); /* tf3 */
529
    skip_bits(&s->gb, 4);
530
    get_bits(&s->gb, 3); /* ap3 */
531
    
532
    /* init size */
533
    width = 720;
534
    if (dsf) {
535
        avctx->frame_rate = 25 * FRAME_RATE_BASE;
536
        packet_size = PAL_FRAME_SIZE;
537
        height = 576;
538
        nb_dif_segs = 12;
539
    } else {
540
        avctx->frame_rate = 30 * FRAME_RATE_BASE;
541
        packet_size = NTSC_FRAME_SIZE;
542
        height = 480;
543
        nb_dif_segs = 10;
544
    }
545
    /* NOTE: we only accept several full frames */
546
    if (buf_size < packet_size)
547
        return -1;
548
    
549
    /* XXX: is it correct to assume that 420 is always used in PAL
550
       mode ? */
551
    s->sampling_411 = !dsf;
552
    if (s->sampling_411) {
553
        mb_pos_ptr = dv_place_411;
554
        avctx->pix_fmt = PIX_FMT_YUV411P;
555
    } else {
556
        mb_pos_ptr = dv_place_420;
557
        avctx->pix_fmt = PIX_FMT_YUV420P;
558
    }
559

    
560
    avctx->width = width;
561
    avctx->height = height;
562

    
563
    s->picture.reference= 0;
564
    if(avctx->get_buffer(avctx, &s->picture) < 0) {
565
        fprintf(stderr, "get_buffer() failed\n");
566
        return -1;
567
    }
568

    
569
    for(i=0;i<3;i++) {
570
        s->current_picture[i] = s->picture.data[i];
571
        s->linesize[i] = s->picture.linesize[i];
572
        if (!s->current_picture[i])
573
            return -1;
574
    }
575
    s->width = width;
576
    s->height = height;
577

    
578
    /* for each DIF segment */
579
    buf_ptr = buf;
580
    for (ds = 0; ds < nb_dif_segs; ds++) {
581
        buf_ptr += 6 * 80; /* skip DIF segment header */
582
        
583
        for(vs = 0; vs < 27; vs++) {
584
            if ((vs % 3) == 0) {
585
                /* skip audio block */
586
                buf_ptr += 80;
587
            }
588
            dv_decode_video_segment(s, buf_ptr, mb_pos_ptr);
589
            buf_ptr += 5 * 80;
590
            mb_pos_ptr += 5;
591
        }
592
    }
593

    
594
    emms_c();
595

    
596
    /* return image */
597
    *data_size = sizeof(AVFrame);
598
    *(AVFrame*)data= s->picture;
599
    
600
    avctx->release_buffer(avctx, &s->picture);
601
    
602
    return packet_size;
603
}
604

    
605
static int dvvideo_decode_end(AVCodecContext *avctx)
606
{
607
    DVVideoDecodeContext *s = avctx->priv_data;
608
    int i;
609
    
610
    if(avctx->get_buffer == avcodec_default_get_buffer){
611
        for(i=0; i<4; i++){
612
            av_freep(&s->picture.base[i]);
613
            s->picture.data[i]= NULL;
614
        }
615
        av_freep(&s->picture.opaque);
616
    }
617

    
618
    return 0;
619
}
620

    
621
AVCodec dvvideo_decoder = {
622
    "dvvideo",
623
    CODEC_TYPE_VIDEO,
624
    CODEC_ID_DVVIDEO,
625
    sizeof(DVVideoDecodeContext),
626
    dvvideo_decode_init,
627
    NULL,
628
    dvvideo_decode_end,
629
    dvvideo_decode_frame,
630
    CODEC_CAP_DR1,
631
    NULL
632
};
633

    
634
typedef struct DVAudioDecodeContext {
635
    AVCodecContext *avctx;
636
    GetBitContext gb;
637
} DVAudioDecodeContext;
638

    
639
static int dvaudio_decode_init(AVCodecContext *avctx)
640
{
641
    //    DVAudioDecodeContext *s = avctx->priv_data;
642
    return 0;
643
}
644

    
645
static uint16_t dv_audio_12to16(uint16_t sample)
646
{
647
    uint16_t shift, result;
648
    
649
    sample = (sample < 0x800) ? sample : sample | 0xf000;
650
    shift = (sample & 0xf00) >> 8;
651

    
652
    if (shift < 0x2 || shift > 0xd) {
653
        result = sample;
654
    } else if (shift < 0x8) {
655
        shift--;
656
        result = (sample - (256 * shift)) << shift;
657
    } else {
658
        shift = 0xe - shift;
659
        result = ((sample + ((256 * shift) + 1)) << shift) - 1;
660
    }
661

    
662
    return result;
663
}
664

    
665
/* NOTE: exactly one frame must be given (120000 bytes for NTSC,
666
   144000 bytes for PAL) 
667

668
   There's a couple of assumptions being made here:
669
         1. We don't do any kind of audio error correction. It means,
670
            that erroneous samples 0x8000 are being passed upwards.
671
            Do we need to silence erroneous samples ? Average them ?
672
         2. We don't do software emphasis.
673
         3. We are not checking for 'speed' argument being valid.
674
         4. Audio is always returned as 16bit linear samples: 12bit
675
            nonlinear samples are converted into 16bit linear ones.
676
*/
677
static int dvaudio_decode_frame(AVCodecContext *avctx, 
678
                                 void *data, int *data_size,
679
                                 uint8_t *buf, int buf_size)
680
{
681
    DVVideoDecodeContext *s = avctx->priv_data;
682
    const uint16_t (*unshuffle)[9];
683
    int smpls, freq, quant, sys, stride, difseg, ad, dp, nb_dif_segs, i;
684
    uint16_t lc, rc;
685
    uint8_t *buf_ptr;
686
    
687
    /* parse id */
688
    init_get_bits(&s->gb, &buf[AAUX_OFFSET], 5*8);
689
    i = get_bits(&s->gb, 8);
690
    if (i != 0x50) { /* No audio ? */
691
        *data_size = 0;
692
        return buf_size;
693
    }
694
    
695
    get_bits(&s->gb, 1); /* 0 - locked audio, 1 - unlocked audio */
696
    skip_bits(&s->gb, 1);
697
    smpls = get_bits(&s->gb, 6); /* samples in this frame - min. samples */
698

    
699
    skip_bits(&s->gb, 8);
700

    
701
    skip_bits(&s->gb, 2);
702
    sys = get_bits(&s->gb, 1); /* 0 - 60 fields, 1 = 50 fields */
703
    skip_bits(&s->gb, 5);
704

    
705
    get_bits(&s->gb, 1); /* 0 - emphasis on, 1 - emphasis off */
706
    get_bits(&s->gb, 1); /* 0 - reserved, 1 - emphasis time constant 50/15us */
707
    freq = get_bits(&s->gb, 3); /* 0 - 48KHz, 1 - 44,1kHz, 2 - 32 kHz */
708
    quant = get_bits(&s->gb, 3); /* 0 - 16bit linear, 1 - 12bit nonlinear */
709

    
710
    if (quant > 1)
711
        return -1; /* Unsupported quantization */
712

    
713
    avctx->sample_rate = dv_audio_frequency[freq];
714
    // What about:
715
    // avctx->bit_rate = 
716
    // avctx->frame_size =
717
   
718
    *data_size = (dv_audio_min_samples[sys][freq] + smpls) * 
719
                 avctx->channels * 2;
720

    
721
    if (sys) {
722
        nb_dif_segs = 12;
723
        stride = 108;
724
        unshuffle = dv_place_audio50;
725
    } else {
726
        nb_dif_segs = 10;
727
        stride = 90;
728
        unshuffle = dv_place_audio60;
729
    }
730
    
731
    /* for each DIF segment */
732
    buf_ptr = buf;
733
    for (difseg = 0; difseg < nb_dif_segs; difseg++) {
734
         buf_ptr += 6 * 80; /* skip DIF segment header */
735
         for (ad = 0; ad < 9; ad++) {
736
              
737
              for (dp = 8; dp < 80; dp+=2) {
738
                   if (quant == 0) {  /* 16bit quantization */
739
                       i = unshuffle[difseg][ad] + (dp - 8)/2 * stride;
740
                       ((short *)data)[i] = (buf_ptr[dp] << 8) | buf_ptr[dp+1]; 
741
                   } else {           /* 12bit quantization */
742
                       if (difseg >= nb_dif_segs/2)
743
                           goto out;  /* We're not doing 4ch at this time */
744
                       
745
                       lc = ((uint16_t)buf_ptr[dp] << 4) | 
746
                            ((uint16_t)buf_ptr[dp+2] >> 4);
747
                       rc = ((uint16_t)buf_ptr[dp+1] << 4) |
748
                            ((uint16_t)buf_ptr[dp+2] & 0x0f);
749
                       lc = dv_audio_12to16(lc);
750
                       rc = dv_audio_12to16(rc);
751

    
752
                       i = unshuffle[difseg][ad] + (dp - 8)/3 * stride;
753
                       ((short *)data)[i] = lc;
754
                       i = unshuffle[difseg+nb_dif_segs/2][ad] + (dp - 8)/3 * stride;
755
                       ((short *)data)[i] = rc;
756
                       ++dp;
757
                   }
758
              }
759
                
760
            buf_ptr += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
761
        }
762
    }
763

    
764
out:
765
    return buf_size;
766
}
767

    
768
static int dvaudio_decode_end(AVCodecContext *avctx)
769
{
770
    //    DVAudioDecodeContext *s = avctx->priv_data;
771
    return 0;
772
}
773

    
774
AVCodec dvaudio_decoder = {
775
    "dvaudio",
776
    CODEC_TYPE_AUDIO,
777
    CODEC_ID_DVAUDIO,
778
    sizeof(DVAudioDecodeContext),
779
    dvaudio_decode_init,
780
    NULL,
781
    dvaudio_decode_end,
782
    dvaudio_decode_frame,
783
    0,
784
    NULL
785
};