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1
/*
2
 * Shorten decoder
3
 * Copyright (c) 2005 Jeff Muizelaar
4
 *
5
 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
8
 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
21

    
22
/**
23
 * @file
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 * Shorten decoder
25
 * @author Jeff Muizelaar
26
 *
27
 */
28

    
29
#define DEBUG
30
#include <limits.h>
31
#include "avcodec.h"
32
#include "get_bits.h"
33
#include "golomb.h"
34

    
35
#define MAX_CHANNELS 8
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#define MAX_BLOCKSIZE 65535
37

    
38
#define OUT_BUFFER_SIZE 16384
39

    
40
#define ULONGSIZE 2
41

    
42
#define WAVE_FORMAT_PCM 0x0001
43

    
44
#define DEFAULT_BLOCK_SIZE 256
45

    
46
#define TYPESIZE 4
47
#define CHANSIZE 0
48
#define LPCQSIZE 2
49
#define ENERGYSIZE 3
50
#define BITSHIFTSIZE 2
51

    
52
#define TYPE_S16HL 3
53
#define TYPE_S16LH 5
54

    
55
#define NWRAP 3
56
#define NSKIPSIZE 1
57

    
58
#define LPCQUANT 5
59
#define V2LPCQOFFSET (1 << LPCQUANT)
60

    
61
#define FNSIZE 2
62
#define FN_DIFF0        0
63
#define FN_DIFF1        1
64
#define FN_DIFF2        2
65
#define FN_DIFF3        3
66
#define FN_QUIT         4
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#define FN_BLOCKSIZE    5
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#define FN_BITSHIFT     6
69
#define FN_QLPC         7
70
#define FN_ZERO         8
71
#define FN_VERBATIM     9
72

    
73
#define VERBATIM_CKSIZE_SIZE 5
74
#define VERBATIM_BYTE_SIZE 8
75
#define CANONICAL_HEADER_SIZE 44
76

    
77
typedef struct ShortenContext {
78
    AVCodecContext *avctx;
79
    GetBitContext gb;
80

    
81
    int min_framesize, max_framesize;
82
    int channels;
83

    
84
    int32_t *decoded[MAX_CHANNELS];
85
    int32_t *offset[MAX_CHANNELS];
86
    int *coeffs;
87
    uint8_t *bitstream;
88
    int bitstream_size;
89
    int bitstream_index;
90
    unsigned int allocated_bitstream_size;
91
    int header_size;
92
    uint8_t header[OUT_BUFFER_SIZE];
93
    int version;
94
    int cur_chan;
95
    int bitshift;
96
    int nmean;
97
    int internal_ftype;
98
    int nwrap;
99
    int blocksize;
100
    int bitindex;
101
    int32_t lpcqoffset;
102
} ShortenContext;
103

    
104
static av_cold int shorten_decode_init(AVCodecContext * avctx)
105
{
106
    ShortenContext *s = avctx->priv_data;
107
    s->avctx = avctx;
108
    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
109

    
110
    return 0;
111
}
112

    
113
static int allocate_buffers(ShortenContext *s)
114
{
115
    int i, chan;
116
    int *coeffs;
117

    
118
    for (chan=0; chan<s->channels; chan++) {
119
        if(FFMAX(1, s->nmean) >= UINT_MAX/sizeof(int32_t)){
120
            av_log(s->avctx, AV_LOG_ERROR, "nmean too large\n");
121
            return -1;
122
        }
123
        if(s->blocksize + s->nwrap >= UINT_MAX/sizeof(int32_t) || s->blocksize + s->nwrap <= (unsigned)s->nwrap){
124
            av_log(s->avctx, AV_LOG_ERROR, "s->blocksize + s->nwrap too large\n");
125
            return -1;
126
        }
127

    
128
        s->offset[chan] = av_realloc(s->offset[chan], sizeof(int32_t)*FFMAX(1, s->nmean));
129

    
130
        s->decoded[chan] = av_realloc(s->decoded[chan], sizeof(int32_t)*(s->blocksize + s->nwrap));
131
        for (i=0; i<s->nwrap; i++)
132
            s->decoded[chan][i] = 0;
133
        s->decoded[chan] += s->nwrap;
134
    }
135

    
136
    coeffs = av_realloc(s->coeffs, s->nwrap * sizeof(*s->coeffs));
137
    if (!coeffs)
138
        return AVERROR(ENOMEM);
139
    s->coeffs = coeffs;
140

    
141
    return 0;
142
}
143

    
144

    
145
static inline unsigned int get_uint(ShortenContext *s, int k)
146
{
147
    if (s->version != 0)
148
        k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
149
    return get_ur_golomb_shorten(&s->gb, k);
150
}
151

    
152

    
153
static void fix_bitshift(ShortenContext *s, int32_t *buffer)
154
{
155
    int i;
156

    
157
    if (s->bitshift != 0)
158
        for (i = 0; i < s->blocksize; i++)
159
            buffer[s->nwrap + i] <<= s->bitshift;
160
}
161

    
162

    
163
static void init_offset(ShortenContext *s)
164
{
165
    int32_t mean = 0;
166
    int  chan, i;
167
    int nblock = FFMAX(1, s->nmean);
168
    /* initialise offset */
169
    switch (s->internal_ftype)
170
    {
171
        case TYPE_S16HL:
172
        case TYPE_S16LH:
173
            mean = 0;
174
            break;
175
        default:
176
            av_log(s->avctx, AV_LOG_ERROR, "unknown audio type");
177
            abort();
178
    }
179

    
180
    for (chan = 0; chan < s->channels; chan++)
181
        for (i = 0; i < nblock; i++)
182
            s->offset[chan][i] = mean;
183
}
184

    
185
static inline int get_le32(GetBitContext *gb)
186
{
187
    return av_bswap32(get_bits_long(gb, 32));
188
}
189

    
190
static inline short get_le16(GetBitContext *gb)
191
{
192
    return av_bswap16(get_bits_long(gb, 16));
193
}
194

    
195
static int decode_wave_header(AVCodecContext *avctx, uint8_t *header, int header_size)
196
{
197
    GetBitContext hb;
198
    int len;
199
    int chunk_size;
200
    short wave_format;
201

    
202
    init_get_bits(&hb, header, header_size*8);
203
    if (get_le32(&hb) != MKTAG('R','I','F','F')) {
204
        av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
205
        return -1;
206
    }
207

    
208
    chunk_size = get_le32(&hb);
209

    
210
    if (get_le32(&hb) != MKTAG('W','A','V','E')) {
211
        av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
212
        return -1;
213
    }
214

    
215
    while (get_le32(&hb) != MKTAG('f','m','t',' ')) {
216
        len = get_le32(&hb);
217
        skip_bits(&hb, 8*len);
218
    }
219
    len = get_le32(&hb);
220

    
221
    if (len < 16) {
222
        av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
223
        return -1;
224
    }
225

    
226
    wave_format = get_le16(&hb);
227

    
228
    switch (wave_format) {
229
        case WAVE_FORMAT_PCM:
230
            break;
231
        default:
232
            av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
233
            return -1;
234
    }
235

    
236
    avctx->channels = get_le16(&hb);
237
    avctx->sample_rate = get_le32(&hb);
238
    avctx->bit_rate = get_le32(&hb) * 8;
239
    avctx->block_align = get_le16(&hb);
240
    avctx->bits_per_coded_sample = get_le16(&hb);
241

    
242
    if (avctx->bits_per_coded_sample != 16) {
243
        av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n");
244
        return -1;
245
    }
246

    
247
    len -= 16;
248
    if (len > 0)
249
        av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
250

    
251
    return 0;
252
}
253

    
254
static int16_t * interleave_buffer(int16_t *samples, int nchan, int blocksize, int32_t **buffer) {
255
    int i, chan;
256
    for (i=0; i<blocksize; i++)
257
        for (chan=0; chan < nchan; chan++)
258
            *samples++ = FFMIN(buffer[chan][i], 32768);
259
    return samples;
260
}
261

    
262
static void decode_subframe_lpc(ShortenContext *s, int channel, int residual_size, int pred_order)
263
{
264
    int sum, i, j;
265
    int *coeffs = s->coeffs;
266

    
267
    for (i=0; i<pred_order; i++)
268
        coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
269

    
270
    for (i=0; i < s->blocksize; i++) {
271
        sum = s->lpcqoffset;
272
        for (j=0; j<pred_order; j++)
273
            sum += coeffs[j] * s->decoded[channel][i-j-1];
274
        s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + (sum >> LPCQUANT);
275
    }
276
}
277

    
278

    
279
static int shorten_decode_frame(AVCodecContext *avctx,
280
        void *data, int *data_size,
281
        AVPacket *avpkt)
282
{
283
    const uint8_t *buf = avpkt->data;
284
    int buf_size = avpkt->size;
285
    ShortenContext *s = avctx->priv_data;
286
    int i, input_buf_size = 0;
287
    int16_t *samples = data;
288
    if(s->max_framesize == 0){
289
        s->max_framesize= 1024; // should hopefully be enough for the first header
290
        s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
291
    }
292

    
293
    if(1 && s->max_framesize){//FIXME truncated
294
        buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
295
        input_buf_size= buf_size;
296

    
297
        if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
298
            //                printf("memmove\n");
299
            memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
300
            s->bitstream_index=0;
301
        }
302
        memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
303
        buf= &s->bitstream[s->bitstream_index];
304
        buf_size += s->bitstream_size;
305
        s->bitstream_size= buf_size;
306

    
307
        if(buf_size < s->max_framesize){
308
            //av_dlog(avctx, "wanna more data ... %d\n", buf_size);
309
            *data_size = 0;
310
            return input_buf_size;
311
        }
312
    }
313
    init_get_bits(&s->gb, buf, buf_size*8);
314
    skip_bits(&s->gb, s->bitindex);
315
    if (!s->blocksize)
316
    {
317
        int maxnlpc = 0;
318
        /* shorten signature */
319
        if (get_bits_long(&s->gb, 32) != AV_RB32("ajkg")) {
320
            av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
321
            return -1;
322
        }
323

    
324
        s->lpcqoffset = 0;
325
        s->blocksize = DEFAULT_BLOCK_SIZE;
326
        s->channels = 1;
327
        s->nmean = -1;
328
        s->version = get_bits(&s->gb, 8);
329
        s->internal_ftype = get_uint(s, TYPESIZE);
330

    
331
        s->channels = get_uint(s, CHANSIZE);
332
        if (s->channels > MAX_CHANNELS) {
333
            av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
334
            return -1;
335
        }
336

    
337
        /* get blocksize if version > 0 */
338
        if (s->version > 0) {
339
            int skip_bytes;
340
            s->blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
341
            maxnlpc = get_uint(s, LPCQSIZE);
342
            s->nmean = get_uint(s, 0);
343

    
344
            skip_bytes = get_uint(s, NSKIPSIZE);
345
            for (i=0; i<skip_bytes; i++) {
346
                skip_bits(&s->gb, 8);
347
            }
348
        }
349
        s->nwrap = FFMAX(NWRAP, maxnlpc);
350

    
351
        if (allocate_buffers(s))
352
            return -1;
353

    
354
        init_offset(s);
355

    
356
        if (s->version > 1)
357
            s->lpcqoffset = V2LPCQOFFSET;
358

    
359
        if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
360
            av_log(s->avctx, AV_LOG_ERROR, "missing verbatim section at beginning of stream\n");
361
            return -1;
362
        }
363

    
364
        s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
365
        if (s->header_size >= OUT_BUFFER_SIZE || s->header_size < CANONICAL_HEADER_SIZE) {
366
            av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n", s->header_size);
367
            return -1;
368
        }
369

    
370
        for (i=0; i<s->header_size; i++)
371
            s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
372

    
373
        if (decode_wave_header(avctx, s->header, s->header_size) < 0)
374
            return -1;
375

    
376
        s->cur_chan = 0;
377
        s->bitshift = 0;
378
    }
379
    else
380
    {
381
        int cmd;
382
        int len;
383
        cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
384
        switch (cmd) {
385
            case FN_ZERO:
386
            case FN_DIFF0:
387
            case FN_DIFF1:
388
            case FN_DIFF2:
389
            case FN_DIFF3:
390
            case FN_QLPC:
391
                {
392
                    int residual_size = 0;
393
                    int channel = s->cur_chan;
394
                    int32_t coffset;
395
                    if (cmd != FN_ZERO) {
396
                        residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
397
                        /* this is a hack as version 0 differed in defintion of get_sr_golomb_shorten */
398
                        if (s->version == 0)
399
                            residual_size--;
400
                    }
401

    
402
                    if (s->nmean == 0)
403
                        coffset = s->offset[channel][0];
404
                    else {
405
                        int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
406
                        for (i=0; i<s->nmean; i++)
407
                            sum += s->offset[channel][i];
408
                        coffset = sum / s->nmean;
409
                        if (s->version >= 2)
410
                            coffset >>= FFMIN(1, s->bitshift);
411
                    }
412
                    switch (cmd) {
413
                        case FN_ZERO:
414
                            for (i=0; i<s->blocksize; i++)
415
                                s->decoded[channel][i] = 0;
416
                            break;
417
                        case FN_DIFF0:
418
                            for (i=0; i<s->blocksize; i++)
419
                                s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + coffset;
420
                            break;
421
                        case FN_DIFF1:
422
                            for (i=0; i<s->blocksize; i++)
423
                                s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + s->decoded[channel][i - 1];
424
                            break;
425
                        case FN_DIFF2:
426
                            for (i=0; i<s->blocksize; i++)
427
                                s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 2*s->decoded[channel][i-1]
428
                                                                                                      -   s->decoded[channel][i-2];
429
                            break;
430
                        case FN_DIFF3:
431
                            for (i=0; i<s->blocksize; i++)
432
                                s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 3*s->decoded[channel][i-1]
433
                                                                                                      - 3*s->decoded[channel][i-2]
434
                                                                                                      +   s->decoded[channel][i-3];
435
                            break;
436
                        case FN_QLPC:
437
                            {
438
                                int pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
439
                                if (pred_order > s->nwrap) {
440
                                    av_log(avctx, AV_LOG_ERROR,
441
                                           "invalid pred_order %d\n",
442
                                           pred_order);
443
                                    return -1;
444
                                }
445
                                for (i=0; i<pred_order; i++)
446
                                    s->decoded[channel][i - pred_order] -= coffset;
447
                                decode_subframe_lpc(s, channel, residual_size, pred_order);
448
                                if (coffset != 0)
449
                                    for (i=0; i < s->blocksize; i++)
450
                                        s->decoded[channel][i] += coffset;
451
                            }
452
                    }
453
                    if (s->nmean > 0) {
454
                        int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
455
                        for (i=0; i<s->blocksize; i++)
456
                            sum += s->decoded[channel][i];
457

    
458
                        for (i=1; i<s->nmean; i++)
459
                            s->offset[channel][i-1] = s->offset[channel][i];
460

    
461
                        if (s->version < 2)
462
                            s->offset[channel][s->nmean - 1] = sum / s->blocksize;
463
                        else
464
                            s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
465
                    }
466
                    for (i=-s->nwrap; i<0; i++)
467
                        s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
468

    
469
                    fix_bitshift(s, s->decoded[channel]);
470

    
471
                    s->cur_chan++;
472
                    if (s->cur_chan == s->channels) {
473
                        samples = interleave_buffer(samples, s->channels, s->blocksize, s->decoded);
474
                        s->cur_chan = 0;
475
                        goto frame_done;
476
                    }
477
                    break;
478
                }
479
                break;
480
            case FN_VERBATIM:
481
                len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
482
                while (len--) {
483
                    get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
484
                }
485
                break;
486
            case FN_BITSHIFT:
487
                s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
488
                break;
489
            case FN_BLOCKSIZE:
490
                s->blocksize = get_uint(s, av_log2(s->blocksize));
491
                break;
492
            case FN_QUIT:
493
                *data_size = 0;
494
                return buf_size;
495
                break;
496
            default:
497
                av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
498
                return -1;
499
                break;
500
        }
501
    }
502
frame_done:
503
    *data_size = (int8_t *)samples - (int8_t *)data;
504

    
505
    //    s->last_blocksize = s->blocksize;
506
    s->bitindex = get_bits_count(&s->gb) - 8*((get_bits_count(&s->gb))/8);
507
    i= (get_bits_count(&s->gb))/8;
508
    if (i > buf_size) {
509
        av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
510
        s->bitstream_size=0;
511
        s->bitstream_index=0;
512
        return -1;
513
    }
514
    if (s->bitstream_size) {
515
        s->bitstream_index += i;
516
        s->bitstream_size  -= i;
517
        return input_buf_size;
518
    } else
519
        return i;
520
}
521

    
522
static av_cold int shorten_decode_close(AVCodecContext *avctx)
523
{
524
    ShortenContext *s = avctx->priv_data;
525
    int i;
526

    
527
    for (i = 0; i < s->channels; i++) {
528
        s->decoded[i] -= s->nwrap;
529
        av_freep(&s->decoded[i]);
530
        av_freep(&s->offset[i]);
531
    }
532
    av_freep(&s->bitstream);
533
    av_freep(&s->coeffs);
534
    return 0;
535
}
536

    
537
static void shorten_flush(AVCodecContext *avctx){
538
    ShortenContext *s = avctx->priv_data;
539

    
540
    s->bitstream_size=
541
        s->bitstream_index= 0;
542
}
543

    
544
AVCodec ff_shorten_decoder = {
545
    "shorten",
546
    AVMEDIA_TYPE_AUDIO,
547
    CODEC_ID_SHORTEN,
548
    sizeof(ShortenContext),
549
    shorten_decode_init,
550
    NULL,
551
    shorten_decode_close,
552
    shorten_decode_frame,
553
    .flush= shorten_flush,
554
    .long_name= NULL_IF_CONFIG_SMALL("Shorten"),
555
};