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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

    
20
/**
21
 * @file dv.c
22
 * DV decoder.
23
 */
24
#include "avcodec.h"
25
#include "dsputil.h"
26
#include "mpegvideo.h"
27
#include "simple_idct.h"
28

    
29
#define NTSC_FRAME_SIZE 120000
30
#define PAL_FRAME_SIZE  144000
31

    
32
#define TEX_VLC_BITS 9
33

    
34
typedef struct DVVideoDecodeContext {
35
    AVCodecContext *avctx;
36
    GetBitContext gb;
37
    VLC *vlc;
38
    int sampling_411; /* 0 = 420, 1 = 411 */
39
    int width, height;
40
    uint8_t *current_picture[3]; /* picture structure */
41
    AVFrame picture;
42
    int linesize[3];
43
    DCTELEM block[5*6][64] __align8;
44
    uint8_t dv_zigzag[2][64];
45
    uint8_t idct_permutation[64];
46
    /* XXX: move it to static storage ? */
47
    uint8_t dv_shift[2][22][64];
48
    void (*idct_put[2])(uint8_t *dest, int line_size, DCTELEM *block);
49
} DVVideoDecodeContext;
50

    
51
#include "dvdata.h"
52

    
53
static VLC dv_vlc;
54
/* XXX: also include quantization */
55
static RL_VLC_ELEM *dv_rl_vlc[1];
56

    
57
static void dv_build_unquantize_tables(DVVideoDecodeContext *s)
58
{
59
    int i, q, j;
60

    
61
    /* NOTE: max left shift is 6 */
62
    for(q = 0; q < 22; q++) {
63
        /* 88 unquant */
64
        for(i = 1; i < 64; i++) {
65
            /* 88 table */
66
            j = s->idct_permutation[i];
67
            s->dv_shift[0][q][j] =
68
                dv_quant_shifts[q][dv_88_areas[i]] + 1;
69
        }
70
        
71
        /* 248 unquant */
72
        for(i = 1; i < 64; i++) {
73
            /* 248 table */
74
            s->dv_shift[1][q][i] =  
75
                    dv_quant_shifts[q][dv_248_areas[i]] + 1;
76
        }
77
    }
78
}
79

    
80
static int dvvideo_decode_init(AVCodecContext *avctx)
81
{
82
    DVVideoDecodeContext *s = avctx->priv_data;
83
    MpegEncContext s2;
84
    static int done=0;
85

    
86
    if (!done) {
87
        int i;
88

    
89
        done = 1;
90

    
91
        /* NOTE: as a trick, we use the fact the no codes are unused
92
           to accelerate the parsing of partial codes */
93
        init_vlc(&dv_vlc, TEX_VLC_BITS, NB_DV_VLC, 
94
                 dv_vlc_len, 1, 1, dv_vlc_bits, 2, 2);
95

    
96
        dv_rl_vlc[0] = av_malloc(dv_vlc.table_size * sizeof(RL_VLC_ELEM));
97
        for(i = 0; i < dv_vlc.table_size; i++){
98
            int code= dv_vlc.table[i][0];
99
            int len = dv_vlc.table[i][1];
100
            int level, run;
101
        
102
            if(len<0){ //more bits needed
103
                run= 0;
104
                level= code;
105
            } else if (code == (NB_DV_VLC - 1)) {
106
                /* EOB */
107
                run = 0;
108
                level = 256;
109
            } else {
110
                run=   dv_vlc_run[code] + 1;
111
                level= dv_vlc_level[code];
112
            }
113
            dv_rl_vlc[0][i].len = len;
114
            dv_rl_vlc[0][i].level = level;
115
            dv_rl_vlc[0][i].run = run;
116
        }
117
    }
118

    
119
    /* ugly way to get the idct & scantable */
120
    /* XXX: fix it */
121
    memset(&s2, 0, sizeof(MpegEncContext));
122
    s2.avctx = avctx;
123
    dsputil_init(&s2.dsp, avctx);
124
    if (DCT_common_init(&s2) < 0)
125
       return -1;
126

    
127
    s->idct_put[0] = s2.dsp.idct_put;
128
    memcpy(s->idct_permutation, s2.dsp.idct_permutation, 64);
129
    memcpy(s->dv_zigzag[0], s2.intra_scantable.permutated, 64);
130

    
131
    /* XXX: use MMX also for idct248 */
132
    s->idct_put[1] = simple_idct248_put;
133
    memcpy(s->dv_zigzag[1], dv_248_zigzag, 64);
134

    
135
    /* XXX: do it only for constant case */
136
    dv_build_unquantize_tables(s);
137
    
138
    return 0;
139
}
140

    
141
//#define VLC_DEBUG
142

    
143
typedef struct BlockInfo {
144
    const uint8_t *shift_table;
145
    const uint8_t *scan_table;
146
    uint8_t pos; /* position in block */
147
    uint8_t eob_reached; /* true if EOB has been reached */
148
    uint8_t dct_mode;
149
    uint8_t partial_bit_count;
150
    uint16_t partial_bit_buffer;
151
    int shift_offset;
152
} BlockInfo;
153

    
154
/* block size in bits */
155
static const uint16_t block_sizes[6] = {
156
    112, 112, 112, 112, 80, 80
157
};
158

    
159
#ifndef ALT_BITSTREAM_READER
160
#error only works with ALT_BITSTREAM_READER
161
#endif
162

    
163
/* decode ac coefs */
164
static void dv_decode_ac(DVVideoDecodeContext *s, 
165
                         BlockInfo *mb, DCTELEM *block, int last_index)
166
{
167
    int last_re_index;
168
    int shift_offset = mb->shift_offset;
169
    const uint8_t *scan_table = mb->scan_table;
170
    const uint8_t *shift_table = mb->shift_table;
171
    int pos = mb->pos;
172
    int level, pos1, sign, run;
173
    int partial_bit_count;
174

    
175
    OPEN_READER(re, &s->gb);
176
    
177
#ifdef VLC_DEBUG
178
    printf("start\n");
179
#endif
180

    
181
    /* if we must parse a partial vlc, we do it here */
182
    partial_bit_count = mb->partial_bit_count;
183
    if (partial_bit_count > 0) {
184
        uint8_t buf[4];
185
        uint32_t v;
186
        int l, l1;
187
        GetBitContext gb1;
188

    
189
        /* build the dummy bit buffer */
190
        l = 16 - partial_bit_count;
191
        UPDATE_CACHE(re, &s->gb);
192
#ifdef VLC_DEBUG
193
        printf("show=%04x\n", SHOW_UBITS(re, &s->gb, 16));
194
#endif
195
        v = (mb->partial_bit_buffer << l) | SHOW_UBITS(re, &s->gb, l);
196
        buf[0] = v >> 8;
197
        buf[1] = v;
198
#ifdef VLC_DEBUG
199
        printf("v=%04x cnt=%d %04x\n", 
200
               v, partial_bit_count, (mb->partial_bit_buffer << l));
201
#endif
202
        /* try to read the codeword */
203
        init_get_bits(&gb1, buf, 4*8);
204
        {
205
            OPEN_READER(re1, &gb1);
206
            UPDATE_CACHE(re1, &gb1);
207
            GET_RL_VLC(level, run, re1, &gb1, dv_rl_vlc[0], 
208
                       TEX_VLC_BITS, 2);
209
            l = re1_index;
210
            CLOSE_READER(re1, &gb1);
211
        }
212
#ifdef VLC_DEBUG
213
        printf("****run=%d level=%d size=%d\n", run, level, l);
214
#endif
215
        /* compute codeword length */
216
        l1 = (level != 256 && level != 0);
217
        /* if too long, we cannot parse */
218
        l -= partial_bit_count;
219
        if ((re_index + l + l1) > last_index)
220
            return;
221
        /* skip read bits */
222
        last_re_index = 0; /* avoid warning */
223
        re_index += l;
224
        /* by definition, if we can read the vlc, all partial bits
225
           will be read (otherwise we could have read the vlc before) */
226
        mb->partial_bit_count = 0;
227
        UPDATE_CACHE(re, &s->gb);
228
        goto handle_vlc;
229
    }
230

    
231
    /* get the AC coefficients until last_index is reached */
232
    for(;;) {
233
        UPDATE_CACHE(re, &s->gb);
234
#ifdef VLC_DEBUG
235
        printf("%2d: bits=%04x index=%d\n", 
236
               pos, SHOW_UBITS(re, &s->gb, 16), re_index);
237
#endif
238
        last_re_index = re_index;
239
        GET_RL_VLC(level, run, re, &s->gb, dv_rl_vlc[0], 
240
                   TEX_VLC_BITS, 2);
241
    handle_vlc:
242
#ifdef VLC_DEBUG
243
        printf("run=%d level=%d\n", run, level);
244
#endif
245
        if (level == 256) {
246
            if (re_index > last_index) {
247
            cannot_read:
248
                /* put position before read code */
249
                re_index = last_re_index;
250
                mb->eob_reached = 0;
251
                break;
252
            }
253
            /* EOB */
254
            mb->eob_reached = 1;
255
            break;
256
        } else if (level != 0) {
257
            if ((re_index + 1) > last_index)
258
                goto cannot_read;
259
            sign = SHOW_SBITS(re, &s->gb, 1);
260
            level = (level ^ sign) - sign;
261
            LAST_SKIP_BITS(re, &s->gb, 1);
262
            pos += run;
263
            /* error */
264
            if (pos >= 64) {
265
                goto read_error;
266
            }
267
            pos1 = scan_table[pos];
268
            level = level << (shift_table[pos1] + shift_offset);
269
            block[pos1] = level;
270
            //            printf("run=%d level=%d shift=%d\n", run, level, shift_table[pos1]);
271
        } else {
272
            if (re_index > last_index)
273
                goto cannot_read;
274
            /* level is zero: means run without coding. No
275
               sign is coded */
276
            pos += run;
277
            /* error */
278
            if (pos >= 64) {
279
            read_error:
280
#if defined(VLC_DEBUG) || 1
281
                printf("error pos=%d\n", pos);
282
#endif
283
                /* for errors, we consider the eob is reached */
284
                mb->eob_reached = 1;
285
                break;
286
            }
287
        }
288
    }
289
    CLOSE_READER(re, &s->gb);
290
    mb->pos = pos;
291
}
292

    
293
static inline void bit_copy(PutBitContext *pb, GetBitContext *gb, int bits_left)
294
{
295
    while (bits_left >= 16) {
296
        put_bits(pb, 16, get_bits(gb, 16));
297
        bits_left -= 16;
298
    }
299
    if (bits_left > 0) {
300
        put_bits(pb, bits_left, get_bits(gb, bits_left));
301
    }
302
}
303

    
304
/* mb_x and mb_y are in units of 8 pixels */
305
static inline void dv_decode_video_segment(DVVideoDecodeContext *s, 
306
                                           uint8_t *buf_ptr1, 
307
                                           const uint16_t *mb_pos_ptr)
308
{
309
    int quant, dc, dct_mode, class1, j;
310
    int mb_index, mb_x, mb_y, v, last_index;
311
    DCTELEM *block, *block1;
312
    int c_offset, bits_left;
313
    uint8_t *y_ptr;
314
    BlockInfo mb_data[5 * 6], *mb, *mb1;
315
    void (*idct_put)(uint8_t *dest, int line_size, DCTELEM *block);
316
    uint8_t *buf_ptr;
317
    PutBitContext pb, vs_pb;
318
    uint8_t mb_bit_buffer[80 + 4]; /* allow some slack */
319
    int mb_bit_count;
320
    uint8_t vs_bit_buffer[5 * 80 + 4]; /* allow some slack */
321
    int vs_bit_count;
322
    
323
    memset(s->block, 0, sizeof(s->block));
324

    
325
    /* pass 1 : read DC and AC coefficients in blocks */
326
    buf_ptr = buf_ptr1;
327
    block1 = &s->block[0][0];
328
    mb1 = mb_data;
329
    init_put_bits(&vs_pb, vs_bit_buffer, 5 * 80, NULL, NULL);
330
    vs_bit_count = 0;
331
    for(mb_index = 0; mb_index < 5; mb_index++) {
332
        /* skip header */
333
        quant = buf_ptr[3] & 0x0f;
334
        buf_ptr += 4;
335
        init_put_bits(&pb, mb_bit_buffer, 80, NULL, NULL);
336
        mb_bit_count = 0;
337
        mb = mb1;
338
        block = block1;
339
        for(j = 0;j < 6; j++) {
340
            /* NOTE: size is not important here */
341
            init_get_bits(&s->gb, buf_ptr, 14*8);
342
            
343
            /* get the dc */
344
            dc = get_bits(&s->gb, 9);
345
            dc = (dc << (32 - 9)) >> (32 - 9);
346
            dct_mode = get_bits1(&s->gb);
347
            mb->dct_mode = dct_mode;
348
            mb->scan_table = s->dv_zigzag[dct_mode];
349
            class1 = get_bits(&s->gb, 2);
350
            mb->shift_offset = (class1 == 3);
351
            mb->shift_table = s->dv_shift[dct_mode]
352
                [quant + dv_quant_offset[class1]];
353
            dc = dc << 2;
354
            /* convert to unsigned because 128 is not added in the
355
               standard IDCT */
356
            dc += 1024;
357
            block[0] = dc;
358
            last_index = block_sizes[j];
359
            buf_ptr += last_index >> 3;
360
            mb->pos = 0;
361
            mb->partial_bit_count = 0;
362

    
363
            dv_decode_ac(s, mb, block, last_index);
364

    
365
            /* write the remaining bits  in a new buffer only if the
366
               block is finished */
367
            bits_left = last_index - s->gb.index;
368
            if (mb->eob_reached) {
369
                mb->partial_bit_count = 0;
370
                mb_bit_count += bits_left;
371
                bit_copy(&pb, &s->gb, bits_left);
372
            } else {
373
                /* should be < 16 bits otherwise a codeword could have
374
                   been parsed */
375
                mb->partial_bit_count = bits_left;
376
                mb->partial_bit_buffer = get_bits(&s->gb, bits_left);
377
            }
378
            block += 64;
379
            mb++;
380
        }
381
        
382
        flush_put_bits(&pb);
383

    
384
        /* pass 2 : we can do it just after */
385
#ifdef VLC_DEBUG
386
        printf("***pass 2 size=%d\n", mb_bit_count);
387
#endif
388
        block = block1;
389
        mb = mb1;
390
        init_get_bits(&s->gb, mb_bit_buffer, 80*8);
391
        for(j = 0;j < 6; j++) {
392
            if (!mb->eob_reached && s->gb.index < mb_bit_count) {
393
                dv_decode_ac(s, mb, block, mb_bit_count);
394
                /* if still not finished, no need to parse other blocks */
395
                if (!mb->eob_reached) {
396
                    /* we could not parse the current AC coefficient,
397
                       so we add the remaining bytes */
398
                    bits_left = mb_bit_count - s->gb.index;
399
                    if (bits_left > 0) {
400
                        mb->partial_bit_count += bits_left;
401
                        mb->partial_bit_buffer = 
402
                            (mb->partial_bit_buffer << bits_left) | 
403
                            get_bits(&s->gb, bits_left);
404
                    }
405
                    goto next_mb;
406
                }
407
            }
408
            block += 64;
409
            mb++;
410
        }
411
        /* all blocks are finished, so the extra bytes can be used at
412
           the video segment level */
413
        bits_left = mb_bit_count - s->gb.index;
414
        vs_bit_count += bits_left;
415
        bit_copy(&vs_pb, &s->gb, bits_left);
416
    next_mb:
417
        mb1 += 6;
418
        block1 += 6 * 64;
419
    }
420

    
421
    /* we need a pass other the whole video segment */
422
    flush_put_bits(&vs_pb);
423
        
424
#ifdef VLC_DEBUG
425
    printf("***pass 3 size=%d\n", vs_bit_count);
426
#endif
427
    block = &s->block[0][0];
428
    mb = mb_data;
429
    init_get_bits(&s->gb, vs_bit_buffer, 5 * 80*8);
430
    for(mb_index = 0; mb_index < 5; mb_index++) {
431
        for(j = 0;j < 6; j++) {
432
            if (!mb->eob_reached) {
433
#ifdef VLC_DEBUG
434
                printf("start %d:%d\n", mb_index, j);
435
#endif
436
                dv_decode_ac(s, mb, block, vs_bit_count);
437
            }
438
            block += 64;
439
            mb++;
440
        }
441
    }
442
    
443
    /* compute idct and place blocks */
444
    block = &s->block[0][0];
445
    mb = mb_data;
446
    for(mb_index = 0; mb_index < 5; mb_index++) {
447
        v = *mb_pos_ptr++;
448
        mb_x = v & 0xff;
449
        mb_y = v >> 8;
450
        y_ptr = s->current_picture[0] + (mb_y * s->linesize[0] * 8) + (mb_x * 8);
451
        if (s->sampling_411)
452
            c_offset = (mb_y * s->linesize[1] * 8) + ((mb_x >> 2) * 8);
453
        else
454
            c_offset = ((mb_y >> 1) * s->linesize[1] * 8) + ((mb_x >> 1) * 8);
455
        for(j = 0;j < 6; j++) {
456
            idct_put = s->idct_put[mb->dct_mode];
457
            if (j < 4) {
458
                if (s->sampling_411 && mb_x < (704 / 8)) {
459
                    /* NOTE: at end of line, the macroblock is handled as 420 */
460
                    idct_put(y_ptr + (j * 8), s->linesize[0], block);
461
                } else {
462
                    idct_put(y_ptr + ((j & 1) * 8) + ((j >> 1) * 8 * s->linesize[0]),
463
                             s->linesize[0], block);
464
                }
465
            } else {
466
                if (s->sampling_411 && mb_x >= (704 / 8)) {
467
                    uint8_t pixels[64], *c_ptr, *c_ptr1, *ptr;
468
                    int y, linesize;
469
                    /* NOTE: at end of line, the macroblock is handled as 420 */
470
                    idct_put(pixels, 8, block);
471
                    linesize = s->linesize[6 - j];
472
                    c_ptr = s->current_picture[6 - j] + c_offset;
473
                    ptr = pixels;
474
                    for(y = 0;y < 8; y++) {
475
                        /* convert to 411P */
476
                        c_ptr1 = c_ptr + linesize;
477
                        c_ptr1[0] = c_ptr[0] = (ptr[0] + ptr[1]) >> 1;
478
                        c_ptr1[1] = c_ptr[1] = (ptr[2] + ptr[3]) >> 1;
479
                        c_ptr1[2] = c_ptr[2] = (ptr[4] + ptr[5]) >> 1;
480
                        c_ptr1[3] = c_ptr[3] = (ptr[6] + ptr[7]) >> 1;
481
                        c_ptr += linesize * 2;
482
                        ptr += 8;
483
                    }
484
                } else {
485
                    /* don't ask me why they inverted Cb and Cr ! */
486
                    idct_put(s->current_picture[6 - j] + c_offset, 
487
                             s->linesize[6 - j], block);
488
                }
489
            }
490
            block += 64;
491
            mb++;
492
        }
493
    }
494
}
495

    
496

    
497
/* NOTE: exactly one frame must be given (120000 bytes for NTSC,
498
   144000 bytes for PAL) */
499
static int dvvideo_decode_frame(AVCodecContext *avctx, 
500
                                 void *data, int *data_size,
501
                                 uint8_t *buf, int buf_size)
502
{
503
    DVVideoDecodeContext *s = avctx->priv_data;
504
    int sct, dsf, apt, ds, nb_dif_segs, vs, width, height, i, packet_size;
505
    uint8_t *buf_ptr;
506
    const uint16_t *mb_pos_ptr;
507
    
508
    /* parse id */
509
    init_get_bits(&s->gb, buf, buf_size*8);
510
    sct = get_bits(&s->gb, 3);
511
    if (sct != 0)
512
        return -1;
513
    skip_bits(&s->gb, 5);
514
    get_bits(&s->gb, 4); /* dsn (sequence number */
515
    get_bits(&s->gb, 1); /* fsc (channel number) */
516
    skip_bits(&s->gb, 3);
517
    get_bits(&s->gb, 8); /* dbn (diff block number 0-134) */
518

    
519
    dsf = get_bits(&s->gb, 1); /* 0 = NTSC 1 = PAL */
520
    if (get_bits(&s->gb, 1) != 0)
521
        return -1;
522
    skip_bits(&s->gb, 11);
523
    apt = get_bits(&s->gb, 3); /* apt */
524

    
525
    get_bits(&s->gb, 1); /* tf1 */
526
    skip_bits(&s->gb, 4);
527
    get_bits(&s->gb, 3); /* ap1 */
528

    
529
    get_bits(&s->gb, 1); /* tf2 */
530
    skip_bits(&s->gb, 4);
531
    get_bits(&s->gb, 3); /* ap2 */
532

    
533
    get_bits(&s->gb, 1); /* tf3 */
534
    skip_bits(&s->gb, 4);
535
    get_bits(&s->gb, 3); /* ap3 */
536
    
537
    /* init size */
538
    width = 720;
539
    if (dsf) {
540
        avctx->frame_rate = 25 * FRAME_RATE_BASE;
541
        packet_size = PAL_FRAME_SIZE;
542
        height = 576;
543
        nb_dif_segs = 12;
544
    } else {
545
        avctx->frame_rate = 30 * FRAME_RATE_BASE;
546
        packet_size = NTSC_FRAME_SIZE;
547
        height = 480;
548
        nb_dif_segs = 10;
549
    }
550
    /* NOTE: we only accept several full frames */
551
    if (buf_size < packet_size)
552
        return -1;
553
    
554
    /* NTSC[dsf == 0] is always 720x480, 4:1:1
555
     *  PAL[dsf == 1] is always 720x576, 4:2:0 for IEC 68134[apt == 0]
556
     *  but for the SMPTE 314M[apt == 1] it is 720x576, 4:1:1
557
     */
558
    s->sampling_411 = !dsf || apt;
559
    if (s->sampling_411) {
560
        mb_pos_ptr = dsf ? dv_place_411P : dv_place_411;
561
        avctx->pix_fmt = PIX_FMT_YUV411P;
562
    } else {
563
        mb_pos_ptr = dv_place_420;
564
        avctx->pix_fmt = PIX_FMT_YUV420P;
565
    }
566

    
567
    avctx->width = width;
568
    avctx->height = height;
569

    
570
    s->picture.reference= 0;
571
    if(avctx->get_buffer(avctx, &s->picture) < 0) {
572
        fprintf(stderr, "get_buffer() failed\n");
573
        return -1;
574
    }
575

    
576
    for(i=0;i<3;i++) {
577
        s->current_picture[i] = s->picture.data[i];
578
        s->linesize[i] = s->picture.linesize[i];
579
        if (!s->current_picture[i])
580
            return -1;
581
    }
582
    s->width = width;
583
    s->height = height;
584

    
585
    /* for each DIF segment */
586
    buf_ptr = buf;
587
    for (ds = 0; ds < nb_dif_segs; ds++) {
588
        buf_ptr += 6 * 80; /* skip DIF segment header */
589
        
590
        for(vs = 0; vs < 27; vs++) {
591
            if ((vs % 3) == 0) {
592
                /* skip audio block */
593
                buf_ptr += 80;
594
            }
595
            dv_decode_video_segment(s, buf_ptr, mb_pos_ptr);
596
            buf_ptr += 5 * 80;
597
            mb_pos_ptr += 5;
598
        }
599
    }
600

    
601
    emms_c();
602

    
603
    /* return image */
604
    *data_size = sizeof(AVFrame);
605
    *(AVFrame*)data= s->picture;
606
    
607
    avctx->release_buffer(avctx, &s->picture);
608
    
609
    return packet_size;
610
}
611

    
612
static int dvvideo_decode_end(AVCodecContext *avctx)
613
{
614
    DVVideoDecodeContext *s = avctx->priv_data;
615
    int i;
616
    
617
    if(avctx->get_buffer == avcodec_default_get_buffer){
618
        for(i=0; i<4; i++){
619
            av_freep(&s->picture.base[i]);
620
            s->picture.data[i]= NULL;
621
        }
622
        av_freep(&s->picture.opaque);
623
    }
624

    
625
    return 0;
626
}
627

    
628
AVCodec dvvideo_decoder = {
629
    "dvvideo",
630
    CODEC_TYPE_VIDEO,
631
    CODEC_ID_DVVIDEO,
632
    sizeof(DVVideoDecodeContext),
633
    dvvideo_decode_init,
634
    NULL,
635
    dvvideo_decode_end,
636
    dvvideo_decode_frame,
637
    CODEC_CAP_DR1,
638
    NULL
639
};
640

    
641
typedef struct DVAudioDecodeContext {
642
    AVCodecContext *avctx;
643
    GetBitContext gb;
644
} DVAudioDecodeContext;
645

    
646
static int dvaudio_decode_init(AVCodecContext *avctx)
647
{
648
    //    DVAudioDecodeContext *s = avctx->priv_data;
649
    return 0;
650
}
651

    
652
static uint16_t dv_audio_12to16(uint16_t sample)
653
{
654
    uint16_t shift, result;
655
    
656
    sample = (sample < 0x800) ? sample : sample | 0xf000;
657
    shift = (sample & 0xf00) >> 8;
658

    
659
    if (shift < 0x2 || shift > 0xd) {
660
        result = sample;
661
    } else if (shift < 0x8) {
662
        shift--;
663
        result = (sample - (256 * shift)) << shift;
664
    } else {
665
        shift = 0xe - shift;
666
        result = ((sample + ((256 * shift) + 1)) << shift) - 1;
667
    }
668

    
669
    return result;
670
}
671

    
672
/* NOTE: exactly one frame must be given (120000 bytes for NTSC,
673
   144000 bytes for PAL) 
674

675
   There's a couple of assumptions being made here:
676
         1. We don't do any kind of audio error correction. It means,
677
            that erroneous samples 0x8000 are being passed upwards.
678
            Do we need to silence erroneous samples ? Average them ?
679
         2. We don't do software emphasis.
680
         3. We are not checking for 'speed' argument being valid.
681
         4. Audio is always returned as 16bit linear samples: 12bit
682
            nonlinear samples are converted into 16bit linear ones.
683
*/
684
static int dvaudio_decode_frame(AVCodecContext *avctx, 
685
                                 void *data, int *data_size,
686
                                 uint8_t *buf, int buf_size)
687
{
688
    DVVideoDecodeContext *s = avctx->priv_data;
689
    const uint16_t (*unshuffle)[9];
690
    int smpls, freq, quant, sys, stride, difseg, ad, dp, nb_dif_segs, i;
691
    uint16_t lc, rc;
692
    uint8_t *buf_ptr;
693
    
694
    /* parse id */
695
    init_get_bits(&s->gb, &buf[AAUX_OFFSET], 5*8);
696
    i = get_bits(&s->gb, 8);
697
    if (i != 0x50) { /* No audio ? */
698
        *data_size = 0;
699
        return buf_size;
700
    }
701
    
702
    get_bits(&s->gb, 1); /* 0 - locked audio, 1 - unlocked audio */
703
    skip_bits(&s->gb, 1);
704
    smpls = get_bits(&s->gb, 6); /* samples in this frame - min. samples */
705

    
706
    skip_bits(&s->gb, 8);
707

    
708
    skip_bits(&s->gb, 2);
709
    sys = get_bits(&s->gb, 1); /* 0 - 60 fields, 1 = 50 fields */
710
    skip_bits(&s->gb, 5);
711

    
712
    get_bits(&s->gb, 1); /* 0 - emphasis on, 1 - emphasis off */
713
    get_bits(&s->gb, 1); /* 0 - reserved, 1 - emphasis time constant 50/15us */
714
    freq = get_bits(&s->gb, 3); /* 0 - 48KHz, 1 - 44,1kHz, 2 - 32 kHz */
715
    quant = get_bits(&s->gb, 3); /* 0 - 16bit linear, 1 - 12bit nonlinear */
716

    
717
    if (quant > 1)
718
        return -1; /* Unsupported quantization */
719

    
720
    avctx->sample_rate = dv_audio_frequency[freq];
721
    // What about:
722
    // avctx->bit_rate = 
723
    // avctx->frame_size =
724
   
725
    *data_size = (dv_audio_min_samples[sys][freq] + smpls) * 
726
                 avctx->channels * 2;
727

    
728
    if (sys) {
729
        nb_dif_segs = 12;
730
        stride = 108;
731
        unshuffle = dv_place_audio50;
732
    } else {
733
        nb_dif_segs = 10;
734
        stride = 90;
735
        unshuffle = dv_place_audio60;
736
    }
737
    
738
    /* for each DIF segment */
739
    buf_ptr = buf;
740
    for (difseg = 0; difseg < nb_dif_segs; difseg++) {
741
         buf_ptr += 6 * 80; /* skip DIF segment header */
742
         for (ad = 0; ad < 9; ad++) {
743
              
744
              for (dp = 8; dp < 80; dp+=2) {
745
                   if (quant == 0) {  /* 16bit quantization */
746
                       i = unshuffle[difseg][ad] + (dp - 8)/2 * stride;
747
                       ((short *)data)[i] = (buf_ptr[dp] << 8) | buf_ptr[dp+1]; 
748
                   } else {           /* 12bit quantization */
749
                       if (difseg >= nb_dif_segs/2)
750
                           goto out;  /* We're not doing 4ch at this time */
751
                       
752
                       lc = ((uint16_t)buf_ptr[dp] << 4) | 
753
                            ((uint16_t)buf_ptr[dp+2] >> 4);
754
                       rc = ((uint16_t)buf_ptr[dp+1] << 4) |
755
                            ((uint16_t)buf_ptr[dp+2] & 0x0f);
756
                       lc = dv_audio_12to16(lc);
757
                       rc = dv_audio_12to16(rc);
758

    
759
                       i = unshuffle[difseg][ad] + (dp - 8)/3 * stride;
760
                       ((short *)data)[i] = lc;
761
                       i = unshuffle[difseg+nb_dif_segs/2][ad] + (dp - 8)/3 * stride;
762
                       ((short *)data)[i] = rc;
763
                       ++dp;
764
                   }
765
              }
766
                
767
            buf_ptr += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
768
        }
769
    }
770

    
771
out:
772
    return buf_size;
773
}
774

    
775
static int dvaudio_decode_end(AVCodecContext *avctx)
776
{
777
    //    DVAudioDecodeContext *s = avctx->priv_data;
778
    return 0;
779
}
780

    
781
AVCodec dvaudio_decoder = {
782
    "dvaudio",
783
    CODEC_TYPE_AUDIO,
784
    CODEC_ID_DVAUDIO,
785
    sizeof(DVAudioDecodeContext),
786
    dvaudio_decode_init,
787
    NULL,
788
    dvaudio_decode_end,
789
    dvaudio_decode_frame,
790
    0,
791
    NULL
792
};