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1
/*
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 * Shorten decoder
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 * Copyright (c) 2005 Jeff Muizelaar
4
 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg 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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 * FFmpeg is distributed in the hope that it will be useful,
13
 * 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 FFmpeg; 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 shorten.c
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 * Shorten decoder
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 * @author Jeff Muizelaar
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 *
27
 */
28

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

    
35
#define MAX_CHANNELS 8
36
#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
68
#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
    uint8_t *bitstream;
87
    int bitstream_size;
88
    int bitstream_index;
89
    unsigned int allocated_bitstream_size;
90
    int header_size;
91
    uint8_t header[OUT_BUFFER_SIZE];
92
    int version;
93
    int cur_chan;
94
    int bitshift;
95
    int nmean;
96
    int internal_ftype;
97
    int nwrap;
98
    int blocksize;
99
    int bitindex;
100
    int32_t lpcqoffset;
101
} ShortenContext;
102

    
103
static int shorten_decode_init(AVCodecContext * avctx)
104
{
105
    ShortenContext *s = avctx->priv_data;
106
    s->avctx = avctx;
107

    
108
    return 0;
109
}
110

    
111
static int allocate_buffers(ShortenContext *s)
112
{
113
    int i, chan;
114
    for (chan=0; chan<s->channels; chan++) {
115
        if(FFMAX(1, s->nmean) >= UINT_MAX/sizeof(int32_t)){
116
            av_log(s->avctx, AV_LOG_ERROR, "nmean too large\n");
117
            return -1;
118
        }
119
        if(s->blocksize + s->nwrap >= UINT_MAX/sizeof(int32_t) || s->blocksize + s->nwrap <= (unsigned)s->nwrap){
120
            av_log(s->avctx, AV_LOG_ERROR, "s->blocksize + s->nwrap too large\n");
121
            return -1;
122
        }
123

    
124
        s->offset[chan] = av_realloc(s->offset[chan], sizeof(int32_t)*FFMAX(1, s->nmean));
125

    
126
        s->decoded[chan] = av_realloc(s->decoded[chan], sizeof(int32_t)*(s->blocksize + s->nwrap));
127
        for (i=0; i<s->nwrap; i++)
128
            s->decoded[chan][i] = 0;
129
        s->decoded[chan] += s->nwrap;
130
    }
131
    return 0;
132
}
133

    
134

    
135
static inline unsigned int get_uint(ShortenContext *s, int k)
136
{
137
    if (s->version != 0)
138
        k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
139
    return get_ur_golomb_shorten(&s->gb, k);
140
}
141

    
142

    
143
static void fix_bitshift(ShortenContext *s, int32_t *buffer)
144
{
145
    int i;
146

    
147
    if (s->bitshift != 0)
148
        for (i = 0; i < s->blocksize; i++)
149
            buffer[s->nwrap + i] <<= s->bitshift;
150
}
151

    
152

    
153
static void init_offset(ShortenContext *s)
154
{
155
    int32_t mean = 0;
156
    int  chan, i;
157
    int nblock = FFMAX(1, s->nmean);
158
    /* initialise offset */
159
    switch (s->internal_ftype)
160
    {
161
        case TYPE_S16HL:
162
        case TYPE_S16LH:
163
            mean = 0;
164
            break;
165
        default:
166
            av_log(s->avctx, AV_LOG_ERROR, "unknown audio type");
167
            abort();
168
    }
169

    
170
    for (chan = 0; chan < s->channels; chan++)
171
        for (i = 0; i < nblock; i++)
172
            s->offset[chan][i] = mean;
173
}
174

    
175
static int inline get_le32(GetBitContext *gb)
176
{
177
    return bswap_32(get_bits_long(gb, 32));
178
}
179

    
180
static short inline get_le16(GetBitContext *gb)
181
{
182
    return bswap_16(get_bits_long(gb, 16));
183
}
184

    
185
static int decode_wave_header(AVCodecContext *avctx, uint8_t *header, int header_size)
186
{
187
    GetBitContext hb;
188
    int len;
189
    int chunk_size;
190
    short wave_format;
191

    
192
    init_get_bits(&hb, header, header_size*8);
193
    if (get_le32(&hb) != MKTAG('R','I','F','F')) {
194
        av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
195
        return -1;
196
    }
197

    
198
    chunk_size = get_le32(&hb);
199

    
200
    if (get_le32(&hb) != MKTAG('W','A','V','E')) {
201
        av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
202
        return -1;
203
    }
204

    
205
    while (get_le32(&hb) != MKTAG('f','m','t',' ')) {
206
        len = get_le32(&hb);
207
        skip_bits(&hb, 8*len);
208
    }
209
    len = get_le32(&hb);
210

    
211
    if (len < 16) {
212
        av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
213
        return -1;
214
    }
215

    
216
    wave_format = get_le16(&hb);
217

    
218
    switch (wave_format) {
219
        case WAVE_FORMAT_PCM:
220
            break;
221
        default:
222
            av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
223
            return -1;
224
    }
225

    
226
    avctx->channels = get_le16(&hb);
227
    avctx->sample_rate = get_le32(&hb);
228
    avctx->bit_rate = get_le32(&hb) * 8;
229
    avctx->block_align = get_le16(&hb);
230
    avctx->bits_per_sample = get_le16(&hb);
231

    
232
    if (avctx->bits_per_sample != 16) {
233
        av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n");
234
        return -1;
235
    }
236

    
237
    len -= 16;
238
    if (len > 0)
239
        av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
240

    
241
    return 0;
242
}
243

    
244
static int16_t * interleave_buffer(int16_t *samples, int nchan, int blocksize, int32_t **buffer) {
245
    int i, chan;
246
    for (i=0; i<blocksize; i++)
247
        for (chan=0; chan < nchan; chan++)
248
            *samples++ = FFMIN(buffer[chan][i], 32768);
249
    return samples;
250
}
251

    
252
static void decode_subframe_lpc(ShortenContext *s, int channel, int residual_size, int pred_order)
253
{
254
    int sum, i, j;
255
    int coeffs[pred_order];
256

    
257
    for (i=0; i<pred_order; i++)
258
        coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
259

    
260
    for (i=0; i < s->blocksize; i++) {
261
        sum = s->lpcqoffset;
262
        for (j=0; j<pred_order; j++)
263
            sum += coeffs[j] * s->decoded[channel][i-j-1];
264
        s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + (sum >> LPCQUANT);
265
    }
266
}
267

    
268

    
269
static int shorten_decode_frame(AVCodecContext *avctx,
270
        void *data, int *data_size,
271
        uint8_t *buf, int buf_size)
272
{
273
    ShortenContext *s = avctx->priv_data;
274
    int i, input_buf_size = 0;
275
    int16_t *samples = data;
276
    if(s->max_framesize == 0){
277
        s->max_framesize= 1024; // should hopefully be enough for the first header
278
        s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
279
    }
280

    
281
    if(1 && s->max_framesize){//FIXME truncated
282
        buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
283
        input_buf_size= buf_size;
284

    
285
        if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
286
            //                printf("memmove\n");
287
            memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
288
            s->bitstream_index=0;
289
        }
290
        memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
291
        buf= &s->bitstream[s->bitstream_index];
292
        buf_size += s->bitstream_size;
293
        s->bitstream_size= buf_size;
294

    
295
        if(buf_size < s->max_framesize){
296
            //dprintf(avctx, "wanna more data ... %d\n", buf_size);
297
            *data_size = 0;
298
            return input_buf_size;
299
        }
300
    }
301
    init_get_bits(&s->gb, buf, buf_size*8);
302
    get_bits(&s->gb, s->bitindex);
303
    if (!s->blocksize)
304
    {
305
        int maxnlpc = 0;
306
        /* shorten signature */
307
        if (get_bits_long(&s->gb, 32) != bswap_32(ff_get_fourcc("ajkg"))) {
308
            av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
309
            return -1;
310
        }
311

    
312
        s->lpcqoffset = 0;
313
        s->blocksize = DEFAULT_BLOCK_SIZE;
314
        s->channels = 1;
315
        s->nmean = -1;
316
        s->version = get_bits(&s->gb, 8);
317
        s->internal_ftype = get_uint(s, TYPESIZE);
318

    
319
        s->channels = get_uint(s, CHANSIZE);
320
        if (s->channels > MAX_CHANNELS) {
321
            av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
322
            return -1;
323
        }
324

    
325
        /* get blocksize if version > 0 */
326
        if (s->version > 0) {
327
            int skip_bytes;
328
            s->blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
329
            maxnlpc = get_uint(s, LPCQSIZE);
330
            s->nmean = get_uint(s, 0);
331

    
332
            skip_bytes = get_uint(s, NSKIPSIZE);
333
            for (i=0; i<skip_bytes; i++) {
334
                skip_bits(&s->gb, 8);
335
            }
336
        }
337
        s->nwrap = FFMAX(NWRAP, maxnlpc);
338

    
339
        if (allocate_buffers(s))
340
            return -1;
341

    
342
        init_offset(s);
343

    
344
        if (s->version > 1)
345
            s->lpcqoffset = V2LPCQOFFSET;
346

    
347
        if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
348
            av_log(s->avctx, AV_LOG_ERROR, "missing verbatim section at begining of stream\n");
349
            return -1;
350
        }
351

    
352
        s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
353
        if (s->header_size >= OUT_BUFFER_SIZE || s->header_size < CANONICAL_HEADER_SIZE) {
354
            av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n", s->header_size);
355
            return -1;
356
        }
357

    
358
        for (i=0; i<s->header_size; i++)
359
            s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
360

    
361
        if (decode_wave_header(avctx, s->header, s->header_size) < 0)
362
            return -1;
363

    
364
        s->cur_chan = 0;
365
        s->bitshift = 0;
366
    }
367
    else
368
    {
369
        int cmd;
370
        int len;
371
        cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
372
        switch (cmd) {
373
            case FN_ZERO:
374
            case FN_DIFF0:
375
            case FN_DIFF1:
376
            case FN_DIFF2:
377
            case FN_DIFF3:
378
            case FN_QLPC:
379
                {
380
                    int residual_size = 0;
381
                    int channel = s->cur_chan;
382
                    int32_t coffset;
383
                    if (cmd != FN_ZERO) {
384
                        residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
385
                        /* this is a hack as version 0 differed in defintion of get_sr_golomb_shorten */
386
                        if (s->version == 0)
387
                            residual_size--;
388
                    }
389

    
390
                    if (s->nmean == 0)
391
                        coffset = s->offset[channel][0];
392
                    else {
393
                        int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
394
                        for (i=0; i<s->nmean; i++)
395
                            sum += s->offset[channel][i];
396
                        coffset = sum / s->nmean;
397
                        if (s->version >= 2)
398
                            coffset >>= FFMIN(1, s->bitshift);
399
                    }
400
                    switch (cmd) {
401
                        case FN_ZERO:
402
                            for (i=0; i<s->blocksize; i++)
403
                                s->decoded[channel][i] = 0;
404
                            break;
405
                        case FN_DIFF0:
406
                            for (i=0; i<s->blocksize; i++)
407
                                s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + coffset;
408
                            break;
409
                        case FN_DIFF1:
410
                            for (i=0; i<s->blocksize; i++)
411
                                s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + s->decoded[channel][i - 1];
412
                            break;
413
                        case FN_DIFF2:
414
                            for (i=0; i<s->blocksize; i++)
415
                                s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 2*s->decoded[channel][i-1]
416
                                                                                                      -   s->decoded[channel][i-2];
417
                            break;
418
                        case FN_DIFF3:
419
                            for (i=0; i<s->blocksize; i++)
420
                                s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 3*s->decoded[channel][i-1]
421
                                                                                                      - 3*s->decoded[channel][i-2]
422
                                                                                                      +   s->decoded[channel][i-3];
423
                            break;
424
                        case FN_QLPC:
425
                            {
426
                                int pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
427
                                for (i=0; i<pred_order; i++)
428
                                    s->decoded[channel][i - pred_order] -= coffset;
429
                                decode_subframe_lpc(s, channel, residual_size, pred_order);
430
                                if (coffset != 0)
431
                                    for (i=0; i < s->blocksize; i++)
432
                                        s->decoded[channel][i] += coffset;
433
                            }
434
                    }
435
                    if (s->nmean > 0) {
436
                        int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
437
                        for (i=0; i<s->blocksize; i++)
438
                            sum += s->decoded[channel][i];
439

    
440
                        for (i=1; i<s->nmean; i++)
441
                            s->offset[channel][i-1] = s->offset[channel][i];
442

    
443
                        if (s->version < 2)
444
                            s->offset[channel][s->nmean - 1] = sum / s->blocksize;
445
                        else
446
                            s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
447
                    }
448
                    for (i=-s->nwrap; i<0; i++)
449
                        s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
450

    
451
                    fix_bitshift(s, s->decoded[channel]);
452

    
453
                    s->cur_chan++;
454
                    if (s->cur_chan == s->channels) {
455
                        samples = interleave_buffer(samples, s->channels, s->blocksize, s->decoded);
456
                        s->cur_chan = 0;
457
                        goto frame_done;
458
                    }
459
                    break;
460
                }
461
                break;
462
            case FN_VERBATIM:
463
                len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
464
                while (len--) {
465
                    get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
466
                }
467
                break;
468
            case FN_BITSHIFT:
469
                s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
470
                break;
471
            case FN_BLOCKSIZE:
472
                s->blocksize = get_uint(s, av_log2(s->blocksize));
473
                break;
474
            case FN_QUIT:
475
                *data_size = 0;
476
                return buf_size;
477
                break;
478
            default:
479
                av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
480
                return -1;
481
                break;
482
        }
483
    }
484
frame_done:
485
    *data_size = (int8_t *)samples - (int8_t *)data;
486

    
487
    //    s->last_blocksize = s->blocksize;
488
    s->bitindex = get_bits_count(&s->gb) - 8*((get_bits_count(&s->gb))/8);
489
    i= (get_bits_count(&s->gb))/8;
490
    if (i > buf_size) {
491
        av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
492
        s->bitstream_size=0;
493
        s->bitstream_index=0;
494
        return -1;
495
    }
496
    if (s->bitstream_size) {
497
        s->bitstream_index += i;
498
        s->bitstream_size  -= i;
499
        return input_buf_size;
500
    } else
501
        return i;
502
}
503

    
504
static int shorten_decode_close(AVCodecContext *avctx)
505
{
506
    ShortenContext *s = avctx->priv_data;
507
    int i;
508

    
509
    for (i = 0; i < s->channels; i++) {
510
        s->decoded[i] -= s->nwrap;
511
        av_freep(&s->decoded[i]);
512
        av_freep(&s->offset[i]);
513
    }
514
    av_freep(&s->bitstream);
515
    return 0;
516
}
517

    
518
static void shorten_flush(AVCodecContext *avctx){
519
    ShortenContext *s = avctx->priv_data;
520

    
521
    s->bitstream_size=
522
        s->bitstream_index= 0;
523
}
524

    
525
AVCodec shorten_decoder = {
526
    "shorten",
527
    CODEC_TYPE_AUDIO,
528
    CODEC_ID_SHORTEN,
529
    sizeof(ShortenContext),
530
    shorten_decode_init,
531
    NULL,
532
    shorten_decode_close,
533
    shorten_decode_frame,
534
    .flush= shorten_flush,
535
};