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1
/**
2
 * FLAC audio encoder
3
 * Copyright (c) 2006  Justin Ruggles <justin.ruggles@gmail.com>
4
 *
5
 * 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
9
 * License as published by the Free Software Foundation; either
10
 * 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
14
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15
 * 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
20
 */
21

    
22
#include "libavutil/crc.h"
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#include "libavutil/lls.h"
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#include "libavutil/md5.h"
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#include "avcodec.h"
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#include "bitstream.h"
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#include "dsputil.h"
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#include "golomb.h"
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#include "lpc.h"
30

    
31
#define FLAC_MAX_CH  8
32
#define FLAC_MIN_BLOCKSIZE  16
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#define FLAC_MAX_BLOCKSIZE  65535
34

    
35
#define FLAC_SUBFRAME_CONSTANT  0
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#define FLAC_SUBFRAME_VERBATIM  1
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#define FLAC_SUBFRAME_FIXED     8
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#define FLAC_SUBFRAME_LPC      32
39

    
40
#define FLAC_CHMODE_NOT_STEREO      0
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#define FLAC_CHMODE_LEFT_RIGHT      1
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#define FLAC_CHMODE_LEFT_SIDE       8
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#define FLAC_CHMODE_RIGHT_SIDE      9
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#define FLAC_CHMODE_MID_SIDE       10
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46
#define FLAC_STREAMINFO_SIZE  34
47

    
48
#define MAX_FIXED_ORDER     4
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#define MAX_PARTITION_ORDER 8
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#define MAX_PARTITIONS     (1 << MAX_PARTITION_ORDER)
51
#define MAX_LPC_PRECISION  15
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#define MAX_LPC_SHIFT      15
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#define MAX_RICE_PARAM     14
54

    
55
typedef struct CompressionOptions {
56
    int compression_level;
57
    int block_time_ms;
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    int use_lpc;
59
    int lpc_coeff_precision;
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    int min_prediction_order;
61
    int max_prediction_order;
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    int prediction_order_method;
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    int min_partition_order;
64
    int max_partition_order;
65
} CompressionOptions;
66

    
67
typedef struct RiceContext {
68
    int porder;
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    int params[MAX_PARTITIONS];
70
} RiceContext;
71

    
72
typedef struct FlacSubframe {
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    int type;
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    int type_code;
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    int obits;
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    int order;
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    int32_t coefs[MAX_LPC_ORDER];
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    int shift;
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    RiceContext rc;
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    int32_t samples[FLAC_MAX_BLOCKSIZE];
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    int32_t residual[FLAC_MAX_BLOCKSIZE+1];
82
} FlacSubframe;
83

    
84
typedef struct FlacFrame {
85
    FlacSubframe subframes[FLAC_MAX_CH];
86
    int blocksize;
87
    int bs_code[2];
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    uint8_t crc8;
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    int ch_mode;
90
} FlacFrame;
91

    
92
typedef struct FlacEncodeContext {
93
    PutBitContext pb;
94
    int channels;
95
    int ch_code;
96
    int samplerate;
97
    int sr_code[2];
98
    int min_framesize;
99
    int min_encoded_framesize;
100
    int max_framesize;
101
    int max_encoded_framesize;
102
    uint32_t frame_count;
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    uint64_t sample_count;
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    uint8_t md5sum[16];
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    FlacFrame frame;
106
    CompressionOptions options;
107
    AVCodecContext *avctx;
108
    DSPContext dsp;
109
    struct AVMD5 *md5ctx;
110
} FlacEncodeContext;
111

    
112
static const int flac_samplerates[16] = {
113
    0, 0, 0, 0,
114
    8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
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    0, 0, 0, 0
116
};
117

    
118
static const int flac_blocksizes[16] = {
119
    0,
120
    192,
121
    576, 1152, 2304, 4608,
122
    0, 0,
123
    256, 512, 1024, 2048, 4096, 8192, 16384, 32768
124
};
125

    
126
/**
127
 * Writes streaminfo metadata block to byte array
128
 */
129
static void write_streaminfo(FlacEncodeContext *s, uint8_t *header)
130
{
131
    PutBitContext pb;
132

    
133
    memset(header, 0, FLAC_STREAMINFO_SIZE);
134
    init_put_bits(&pb, header, FLAC_STREAMINFO_SIZE);
135

    
136
    /* streaminfo metadata block */
137
    put_bits(&pb, 16, s->avctx->frame_size);
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    put_bits(&pb, 16, s->avctx->frame_size);
139
    put_bits(&pb, 24, s->min_framesize);
140
    put_bits(&pb, 24, s->max_framesize);
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    put_bits(&pb, 20, s->samplerate);
142
    put_bits(&pb, 3, s->channels-1);
143
    put_bits(&pb, 5, 15);       /* bits per sample - 1 */
144
    /* write 36-bit sample count in 2 put_bits() calls */
145
    put_bits(&pb, 24, (s->sample_count & 0xFFFFFF000LL) >> 12);
146
    put_bits(&pb, 12,  s->sample_count & 0x000000FFFLL);
147
    flush_put_bits(&pb);
148
    memcpy(&header[18], s->md5sum, 16);
149
}
150

    
151
/**
152
 * Sets blocksize based on samplerate
153
 * Chooses the closest predefined blocksize >= BLOCK_TIME_MS milliseconds
154
 */
155
static int select_blocksize(int samplerate, int block_time_ms)
156
{
157
    int i;
158
    int target;
159
    int blocksize;
160

    
161
    assert(samplerate > 0);
162
    blocksize = flac_blocksizes[1];
163
    target = (samplerate * block_time_ms) / 1000;
164
    for(i=0; i<16; i++) {
165
        if(target >= flac_blocksizes[i] && flac_blocksizes[i] > blocksize) {
166
            blocksize = flac_blocksizes[i];
167
        }
168
    }
169
    return blocksize;
170
}
171

    
172
static av_cold int flac_encode_init(AVCodecContext *avctx)
173
{
174
    int freq = avctx->sample_rate;
175
    int channels = avctx->channels;
176
    FlacEncodeContext *s = avctx->priv_data;
177
    int i, level;
178
    uint8_t *streaminfo;
179

    
180
    s->avctx = avctx;
181

    
182
    dsputil_init(&s->dsp, avctx);
183

    
184
    if(avctx->sample_fmt != SAMPLE_FMT_S16) {
185
        return -1;
186
    }
187

    
188
    if(channels < 1 || channels > FLAC_MAX_CH) {
189
        return -1;
190
    }
191
    s->channels = channels;
192
    s->ch_code = s->channels-1;
193

    
194
    /* find samplerate in table */
195
    if(freq < 1)
196
        return -1;
197
    for(i=4; i<12; i++) {
198
        if(freq == flac_samplerates[i]) {
199
            s->samplerate = flac_samplerates[i];
200
            s->sr_code[0] = i;
201
            s->sr_code[1] = 0;
202
            break;
203
        }
204
    }
205
    /* if not in table, samplerate is non-standard */
206
    if(i == 12) {
207
        if(freq % 1000 == 0 && freq < 255000) {
208
            s->sr_code[0] = 12;
209
            s->sr_code[1] = freq / 1000;
210
        } else if(freq % 10 == 0 && freq < 655350) {
211
            s->sr_code[0] = 14;
212
            s->sr_code[1] = freq / 10;
213
        } else if(freq < 65535) {
214
            s->sr_code[0] = 13;
215
            s->sr_code[1] = freq;
216
        } else {
217
            return -1;
218
        }
219
        s->samplerate = freq;
220
    }
221

    
222
    /* set compression option defaults based on avctx->compression_level */
223
    if(avctx->compression_level < 0) {
224
        s->options.compression_level = 5;
225
    } else {
226
        s->options.compression_level = avctx->compression_level;
227
    }
228
    av_log(avctx, AV_LOG_DEBUG, " compression: %d\n", s->options.compression_level);
229

    
230
    level= s->options.compression_level;
231
    if(level > 12) {
232
        av_log(avctx, AV_LOG_ERROR, "invalid compression level: %d\n",
233
               s->options.compression_level);
234
        return -1;
235
    }
236

    
237
    s->options.block_time_ms       = ((int[]){ 27, 27, 27,105,105,105,105,105,105,105,105,105,105})[level];
238
    s->options.use_lpc             = ((int[]){  0,  0,  0,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1})[level];
239
    s->options.min_prediction_order= ((int[]){  2,  0,  0,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1})[level];
240
    s->options.max_prediction_order= ((int[]){  3,  4,  4,  6,  8,  8,  8,  8, 12, 12, 12, 32, 32})[level];
241
    s->options.prediction_order_method = ((int[]){ ORDER_METHOD_EST,    ORDER_METHOD_EST,    ORDER_METHOD_EST,
242
                                                   ORDER_METHOD_EST,    ORDER_METHOD_EST,    ORDER_METHOD_EST,
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                                                   ORDER_METHOD_4LEVEL, ORDER_METHOD_LOG,    ORDER_METHOD_4LEVEL,
244
                                                   ORDER_METHOD_LOG,    ORDER_METHOD_SEARCH, ORDER_METHOD_LOG,
245
                                                   ORDER_METHOD_SEARCH})[level];
246
    s->options.min_partition_order = ((int[]){  2,  2,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0})[level];
247
    s->options.max_partition_order = ((int[]){  2,  2,  3,  3,  3,  8,  8,  8,  8,  8,  8,  8,  8})[level];
248

    
249
    /* set compression option overrides from AVCodecContext */
250
    if(avctx->use_lpc >= 0) {
251
        s->options.use_lpc = av_clip(avctx->use_lpc, 0, 11);
252
    }
253
    if(s->options.use_lpc == 1)
254
        av_log(avctx, AV_LOG_DEBUG, " use lpc: Levinson-Durbin recursion with Welch window\n");
255
    else if(s->options.use_lpc > 1)
256
        av_log(avctx, AV_LOG_DEBUG, " use lpc: Cholesky factorization\n");
257

    
258
    if(avctx->min_prediction_order >= 0) {
259
        if(s->options.use_lpc) {
260
            if(avctx->min_prediction_order < MIN_LPC_ORDER ||
261
                    avctx->min_prediction_order > MAX_LPC_ORDER) {
262
                av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
263
                       avctx->min_prediction_order);
264
                return -1;
265
            }
266
        } else {
267
            if(avctx->min_prediction_order > MAX_FIXED_ORDER) {
268
                av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
269
                       avctx->min_prediction_order);
270
                return -1;
271
            }
272
        }
273
        s->options.min_prediction_order = avctx->min_prediction_order;
274
    }
275
    if(avctx->max_prediction_order >= 0) {
276
        if(s->options.use_lpc) {
277
            if(avctx->max_prediction_order < MIN_LPC_ORDER ||
278
                    avctx->max_prediction_order > MAX_LPC_ORDER) {
279
                av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
280
                       avctx->max_prediction_order);
281
                return -1;
282
            }
283
        } else {
284
            if(avctx->max_prediction_order > MAX_FIXED_ORDER) {
285
                av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
286
                       avctx->max_prediction_order);
287
                return -1;
288
            }
289
        }
290
        s->options.max_prediction_order = avctx->max_prediction_order;
291
    }
292
    if(s->options.max_prediction_order < s->options.min_prediction_order) {
293
        av_log(avctx, AV_LOG_ERROR, "invalid prediction orders: min=%d max=%d\n",
294
               s->options.min_prediction_order, s->options.max_prediction_order);
295
        return -1;
296
    }
297
    av_log(avctx, AV_LOG_DEBUG, " prediction order: %d, %d\n",
298
           s->options.min_prediction_order, s->options.max_prediction_order);
299

    
300
    if(avctx->prediction_order_method >= 0) {
301
        if(avctx->prediction_order_method > ORDER_METHOD_LOG) {
302
            av_log(avctx, AV_LOG_ERROR, "invalid prediction order method: %d\n",
303
                   avctx->prediction_order_method);
304
            return -1;
305
        }
306
        s->options.prediction_order_method = avctx->prediction_order_method;
307
    }
308
    switch(s->options.prediction_order_method) {
309
        case ORDER_METHOD_EST:    av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
310
                                         "estimate"); break;
311
        case ORDER_METHOD_2LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
312
                                         "2-level"); break;
313
        case ORDER_METHOD_4LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
314
                                         "4-level"); break;
315
        case ORDER_METHOD_8LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
316
                                         "8-level"); break;
317
        case ORDER_METHOD_SEARCH: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
318
                                         "full search"); break;
319
        case ORDER_METHOD_LOG:    av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
320
                                         "log search"); break;
321
    }
322

    
323
    if(avctx->min_partition_order >= 0) {
324
        if(avctx->min_partition_order > MAX_PARTITION_ORDER) {
325
            av_log(avctx, AV_LOG_ERROR, "invalid min partition order: %d\n",
326
                   avctx->min_partition_order);
327
            return -1;
328
        }
329
        s->options.min_partition_order = avctx->min_partition_order;
330
    }
331
    if(avctx->max_partition_order >= 0) {
332
        if(avctx->max_partition_order > MAX_PARTITION_ORDER) {
333
            av_log(avctx, AV_LOG_ERROR, "invalid max partition order: %d\n",
334
                   avctx->max_partition_order);
335
            return -1;
336
        }
337
        s->options.max_partition_order = avctx->max_partition_order;
338
    }
339
    if(s->options.max_partition_order < s->options.min_partition_order) {
340
        av_log(avctx, AV_LOG_ERROR, "invalid partition orders: min=%d max=%d\n",
341
               s->options.min_partition_order, s->options.max_partition_order);
342
        return -1;
343
    }
344
    av_log(avctx, AV_LOG_DEBUG, " partition order: %d, %d\n",
345
           s->options.min_partition_order, s->options.max_partition_order);
346

    
347
    if(avctx->frame_size > 0) {
348
        if(avctx->frame_size < FLAC_MIN_BLOCKSIZE ||
349
                avctx->frame_size > FLAC_MAX_BLOCKSIZE) {
350
            av_log(avctx, AV_LOG_ERROR, "invalid block size: %d\n",
351
                   avctx->frame_size);
352
            return -1;
353
        }
354
    } else {
355
        s->avctx->frame_size = select_blocksize(s->samplerate, s->options.block_time_ms);
356
    }
357
    av_log(avctx, AV_LOG_DEBUG, " block size: %d\n", s->avctx->frame_size);
358

    
359
    /* set LPC precision */
360
    if(avctx->lpc_coeff_precision > 0) {
361
        if(avctx->lpc_coeff_precision > MAX_LPC_PRECISION) {
362
            av_log(avctx, AV_LOG_ERROR, "invalid lpc coeff precision: %d\n",
363
                   avctx->lpc_coeff_precision);
364
            return -1;
365
        }
366
        s->options.lpc_coeff_precision = avctx->lpc_coeff_precision;
367
    } else {
368
        /* default LPC precision */
369
        s->options.lpc_coeff_precision = 15;
370
    }
371
    av_log(avctx, AV_LOG_DEBUG, " lpc precision: %d\n",
372
           s->options.lpc_coeff_precision);
373

    
374
    /* set maximum encoded frame size in verbatim mode */
375
    if(s->channels == 2) {
376
        s->max_framesize = 14 + ((s->avctx->frame_size * 33 + 7) >> 3);
377
    } else {
378
        s->max_framesize = 14 + (s->avctx->frame_size * s->channels * 2);
379
    }
380
    s->min_encoded_framesize = 0xFFFFFF;
381

    
382
    /* initialize MD5 context */
383
    s->md5ctx = av_malloc(av_md5_size);
384
    if(!s->md5ctx)
385
        return AVERROR_NOMEM;
386
    av_md5_init(s->md5ctx);
387

    
388
    streaminfo = av_malloc(FLAC_STREAMINFO_SIZE);
389
    write_streaminfo(s, streaminfo);
390
    avctx->extradata = streaminfo;
391
    avctx->extradata_size = FLAC_STREAMINFO_SIZE;
392

    
393
    s->frame_count = 0;
394

    
395
    avctx->coded_frame = avcodec_alloc_frame();
396
    avctx->coded_frame->key_frame = 1;
397

    
398
    return 0;
399
}
400

    
401
static void init_frame(FlacEncodeContext *s)
402
{
403
    int i, ch;
404
    FlacFrame *frame;
405

    
406
    frame = &s->frame;
407

    
408
    for(i=0; i<16; i++) {
409
        if(s->avctx->frame_size == flac_blocksizes[i]) {
410
            frame->blocksize = flac_blocksizes[i];
411
            frame->bs_code[0] = i;
412
            frame->bs_code[1] = 0;
413
            break;
414
        }
415
    }
416
    if(i == 16) {
417
        frame->blocksize = s->avctx->frame_size;
418
        if(frame->blocksize <= 256) {
419
            frame->bs_code[0] = 6;
420
            frame->bs_code[1] = frame->blocksize-1;
421
        } else {
422
            frame->bs_code[0] = 7;
423
            frame->bs_code[1] = frame->blocksize-1;
424
        }
425
    }
426

    
427
    for(ch=0; ch<s->channels; ch++) {
428
        frame->subframes[ch].obits = 16;
429
    }
430
}
431

    
432
/**
433
 * Copy channel-interleaved input samples into separate subframes
434
 */
435
static void copy_samples(FlacEncodeContext *s, int16_t *samples)
436
{
437
    int i, j, ch;
438
    FlacFrame *frame;
439

    
440
    frame = &s->frame;
441
    for(i=0,j=0; i<frame->blocksize; i++) {
442
        for(ch=0; ch<s->channels; ch++,j++) {
443
            frame->subframes[ch].samples[i] = samples[j];
444
        }
445
    }
446
}
447

    
448

    
449
#define rice_encode_count(sum, n, k) (((n)*((k)+1))+((sum-(n>>1))>>(k)))
450

    
451
/**
452
 * Solve for d/dk(rice_encode_count) = n-((sum-(n>>1))>>(k+1)) = 0
453
 */
454
static int find_optimal_param(uint32_t sum, int n)
455
{
456
    int k;
457
    uint32_t sum2;
458

    
459
    if(sum <= n>>1)
460
        return 0;
461
    sum2 = sum-(n>>1);
462
    k = av_log2(n<256 ? FASTDIV(sum2,n) : sum2/n);
463
    return FFMIN(k, MAX_RICE_PARAM);
464
}
465

    
466
static uint32_t calc_optimal_rice_params(RiceContext *rc, int porder,
467
                                         uint32_t *sums, int n, int pred_order)
468
{
469
    int i;
470
    int k, cnt, part;
471
    uint32_t all_bits;
472

    
473
    part = (1 << porder);
474
    all_bits = 4 * part;
475

    
476
    cnt = (n >> porder) - pred_order;
477
    for(i=0; i<part; i++) {
478
        k = find_optimal_param(sums[i], cnt);
479
        rc->params[i] = k;
480
        all_bits += rice_encode_count(sums[i], cnt, k);
481
        cnt = n >> porder;
482
    }
483

    
484
    rc->porder = porder;
485

    
486
    return all_bits;
487
}
488

    
489
static void calc_sums(int pmin, int pmax, uint32_t *data, int n, int pred_order,
490
                      uint32_t sums[][MAX_PARTITIONS])
491
{
492
    int i, j;
493
    int parts;
494
    uint32_t *res, *res_end;
495

    
496
    /* sums for highest level */
497
    parts = (1 << pmax);
498
    res = &data[pred_order];
499
    res_end = &data[n >> pmax];
500
    for(i=0; i<parts; i++) {
501
        uint32_t sum = 0;
502
        while(res < res_end){
503
            sum += *(res++);
504
        }
505
        sums[pmax][i] = sum;
506
        res_end+= n >> pmax;
507
    }
508
    /* sums for lower levels */
509
    for(i=pmax-1; i>=pmin; i--) {
510
        parts = (1 << i);
511
        for(j=0; j<parts; j++) {
512
            sums[i][j] = sums[i+1][2*j] + sums[i+1][2*j+1];
513
        }
514
    }
515
}
516

    
517
static uint32_t calc_rice_params(RiceContext *rc, int pmin, int pmax,
518
                                 int32_t *data, int n, int pred_order)
519
{
520
    int i;
521
    uint32_t bits[MAX_PARTITION_ORDER+1];
522
    int opt_porder;
523
    RiceContext tmp_rc;
524
    uint32_t *udata;
525
    uint32_t sums[MAX_PARTITION_ORDER+1][MAX_PARTITIONS];
526

    
527
    assert(pmin >= 0 && pmin <= MAX_PARTITION_ORDER);
528
    assert(pmax >= 0 && pmax <= MAX_PARTITION_ORDER);
529
    assert(pmin <= pmax);
530

    
531
    udata = av_malloc(n * sizeof(uint32_t));
532
    for(i=0; i<n; i++) {
533
        udata[i] = (2*data[i]) ^ (data[i]>>31);
534
    }
535

    
536
    calc_sums(pmin, pmax, udata, n, pred_order, sums);
537

    
538
    opt_porder = pmin;
539
    bits[pmin] = UINT32_MAX;
540
    for(i=pmin; i<=pmax; i++) {
541
        bits[i] = calc_optimal_rice_params(&tmp_rc, i, sums[i], n, pred_order);
542
        if(bits[i] <= bits[opt_porder]) {
543
            opt_porder = i;
544
            *rc= tmp_rc;
545
        }
546
    }
547

    
548
    av_freep(&udata);
549
    return bits[opt_porder];
550
}
551

    
552
static int get_max_p_order(int max_porder, int n, int order)
553
{
554
    int porder = FFMIN(max_porder, av_log2(n^(n-1)));
555
    if(order > 0)
556
        porder = FFMIN(porder, av_log2(n/order));
557
    return porder;
558
}
559

    
560
static uint32_t calc_rice_params_fixed(RiceContext *rc, int pmin, int pmax,
561
                                       int32_t *data, int n, int pred_order,
562
                                       int bps)
563
{
564
    uint32_t bits;
565
    pmin = get_max_p_order(pmin, n, pred_order);
566
    pmax = get_max_p_order(pmax, n, pred_order);
567
    bits = pred_order*bps + 6;
568
    bits += calc_rice_params(rc, pmin, pmax, data, n, pred_order);
569
    return bits;
570
}
571

    
572
static uint32_t calc_rice_params_lpc(RiceContext *rc, int pmin, int pmax,
573
                                     int32_t *data, int n, int pred_order,
574
                                     int bps, int precision)
575
{
576
    uint32_t bits;
577
    pmin = get_max_p_order(pmin, n, pred_order);
578
    pmax = get_max_p_order(pmax, n, pred_order);
579
    bits = pred_order*bps + 4 + 5 + pred_order*precision + 6;
580
    bits += calc_rice_params(rc, pmin, pmax, data, n, pred_order);
581
    return bits;
582
}
583

    
584
/**
585
 * Apply Welch window function to audio block
586
 */
587
static void apply_welch_window(const int32_t *data, int len, double *w_data)
588
{
589
    int i, n2;
590
    double w;
591
    double c;
592

    
593
    assert(!(len&1)); //the optimization in r11881 does not support odd len
594
                      //if someone wants odd len extend the change in r11881
595

    
596
    n2 = (len >> 1);
597
    c = 2.0 / (len - 1.0);
598

    
599
    w_data+=n2;
600
      data+=n2;
601
    for(i=0; i<n2; i++) {
602
        w = c - n2 + i;
603
        w = 1.0 - (w * w);
604
        w_data[-i-1] = data[-i-1] * w;
605
        w_data[+i  ] = data[+i  ] * w;
606
    }
607
}
608

    
609
/**
610
 * Calculates autocorrelation data from audio samples
611
 * A Welch window function is applied before calculation.
612
 */
613
void ff_flac_compute_autocorr(const int32_t *data, int len, int lag,
614
                              double *autoc)
615
{
616
    int i, j;
617
    double tmp[len + lag + 1];
618
    double *data1= tmp + lag;
619

    
620
    apply_welch_window(data, len, data1);
621

    
622
    for(j=0; j<lag; j++)
623
        data1[j-lag]= 0.0;
624
    data1[len] = 0.0;
625

    
626
    for(j=0; j<lag; j+=2){
627
        double sum0 = 1.0, sum1 = 1.0;
628
        for(i=0; i<len; i++){
629
            sum0 += data1[i] * data1[i-j];
630
            sum1 += data1[i] * data1[i-j-1];
631
        }
632
        autoc[j  ] = sum0;
633
        autoc[j+1] = sum1;
634
    }
635

    
636
    if(j==lag){
637
        double sum = 1.0;
638
        for(i=0; i<len; i+=2){
639
            sum += data1[i  ] * data1[i-j  ]
640
                 + data1[i+1] * data1[i-j+1];
641
        }
642
        autoc[j] = sum;
643
    }
644
}
645

    
646

    
647
static void encode_residual_verbatim(int32_t *res, int32_t *smp, int n)
648
{
649
    assert(n > 0);
650
    memcpy(res, smp, n * sizeof(int32_t));
651
}
652

    
653
static void encode_residual_fixed(int32_t *res, const int32_t *smp, int n,
654
                                  int order)
655
{
656
    int i;
657

    
658
    for(i=0; i<order; i++) {
659
        res[i] = smp[i];
660
    }
661

    
662
    if(order==0){
663
        for(i=order; i<n; i++)
664
            res[i]= smp[i];
665
    }else if(order==1){
666
        for(i=order; i<n; i++)
667
            res[i]= smp[i] - smp[i-1];
668
    }else if(order==2){
669
        int a = smp[order-1] - smp[order-2];
670
        for(i=order; i<n; i+=2) {
671
            int b = smp[i] - smp[i-1];
672
            res[i]= b - a;
673
            a = smp[i+1] - smp[i];
674
            res[i+1]= a - b;
675
        }
676
    }else if(order==3){
677
        int a = smp[order-1] - smp[order-2];
678
        int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
679
        for(i=order; i<n; i+=2) {
680
            int b = smp[i] - smp[i-1];
681
            int d = b - a;
682
            res[i]= d - c;
683
            a = smp[i+1] - smp[i];
684
            c = a - b;
685
            res[i+1]= c - d;
686
        }
687
    }else{
688
        int a = smp[order-1] - smp[order-2];
689
        int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
690
        int e = smp[order-1] - 3*smp[order-2] + 3*smp[order-3] - smp[order-4];
691
        for(i=order; i<n; i+=2) {
692
            int b = smp[i] - smp[i-1];
693
            int d = b - a;
694
            int f = d - c;
695
            res[i]= f - e;
696
            a = smp[i+1] - smp[i];
697
            c = a - b;
698
            e = c - d;
699
            res[i+1]= e - f;
700
        }
701
    }
702
}
703

    
704
#define LPC1(x) {\
705
    int c = coefs[(x)-1];\
706
    p0 += c*s;\
707
    s = smp[i-(x)+1];\
708
    p1 += c*s;\
709
}
710

    
711
static av_always_inline void encode_residual_lpc_unrolled(
712
    int32_t *res, const int32_t *smp, int n,
713
    int order, const int32_t *coefs, int shift, int big)
714
{
715
    int i;
716
    for(i=order; i<n; i+=2) {
717
        int s = smp[i-order];
718
        int p0 = 0, p1 = 0;
719
        if(big) {
720
            switch(order) {
721
                case 32: LPC1(32)
722
                case 31: LPC1(31)
723
                case 30: LPC1(30)
724
                case 29: LPC1(29)
725
                case 28: LPC1(28)
726
                case 27: LPC1(27)
727
                case 26: LPC1(26)
728
                case 25: LPC1(25)
729
                case 24: LPC1(24)
730
                case 23: LPC1(23)
731
                case 22: LPC1(22)
732
                case 21: LPC1(21)
733
                case 20: LPC1(20)
734
                case 19: LPC1(19)
735
                case 18: LPC1(18)
736
                case 17: LPC1(17)
737
                case 16: LPC1(16)
738
                case 15: LPC1(15)
739
                case 14: LPC1(14)
740
                case 13: LPC1(13)
741
                case 12: LPC1(12)
742
                case 11: LPC1(11)
743
                case 10: LPC1(10)
744
                case  9: LPC1( 9)
745
                         LPC1( 8)
746
                         LPC1( 7)
747
                         LPC1( 6)
748
                         LPC1( 5)
749
                         LPC1( 4)
750
                         LPC1( 3)
751
                         LPC1( 2)
752
                         LPC1( 1)
753
            }
754
        } else {
755
            switch(order) {
756
                case  8: LPC1( 8)
757
                case  7: LPC1( 7)
758
                case  6: LPC1( 6)
759
                case  5: LPC1( 5)
760
                case  4: LPC1( 4)
761
                case  3: LPC1( 3)
762
                case  2: LPC1( 2)
763
                case  1: LPC1( 1)
764
            }
765
        }
766
        res[i  ] = smp[i  ] - (p0 >> shift);
767
        res[i+1] = smp[i+1] - (p1 >> shift);
768
    }
769
}
770

    
771
static void encode_residual_lpc(int32_t *res, const int32_t *smp, int n,
772
                                int order, const int32_t *coefs, int shift)
773
{
774
    int i;
775
    for(i=0; i<order; i++) {
776
        res[i] = smp[i];
777
    }
778
#ifdef CONFIG_SMALL
779
    for(i=order; i<n; i+=2) {
780
        int j;
781
        int s = smp[i];
782
        int p0 = 0, p1 = 0;
783
        for(j=0; j<order; j++) {
784
            int c = coefs[j];
785
            p1 += c*s;
786
            s = smp[i-j-1];
787
            p0 += c*s;
788
        }
789
        res[i  ] = smp[i  ] - (p0 >> shift);
790
        res[i+1] = smp[i+1] - (p1 >> shift);
791
    }
792
#else
793
    switch(order) {
794
        case  1: encode_residual_lpc_unrolled(res, smp, n, 1, coefs, shift, 0); break;
795
        case  2: encode_residual_lpc_unrolled(res, smp, n, 2, coefs, shift, 0); break;
796
        case  3: encode_residual_lpc_unrolled(res, smp, n, 3, coefs, shift, 0); break;
797
        case  4: encode_residual_lpc_unrolled(res, smp, n, 4, coefs, shift, 0); break;
798
        case  5: encode_residual_lpc_unrolled(res, smp, n, 5, coefs, shift, 0); break;
799
        case  6: encode_residual_lpc_unrolled(res, smp, n, 6, coefs, shift, 0); break;
800
        case  7: encode_residual_lpc_unrolled(res, smp, n, 7, coefs, shift, 0); break;
801
        case  8: encode_residual_lpc_unrolled(res, smp, n, 8, coefs, shift, 0); break;
802
        default: encode_residual_lpc_unrolled(res, smp, n, order, coefs, shift, 1); break;
803
    }
804
#endif
805
}
806

    
807
static int encode_residual(FlacEncodeContext *ctx, int ch)
808
{
809
    int i, n;
810
    int min_order, max_order, opt_order, precision, omethod;
811
    int min_porder, max_porder;
812
    FlacFrame *frame;
813
    FlacSubframe *sub;
814
    int32_t coefs[MAX_LPC_ORDER][MAX_LPC_ORDER];
815
    int shift[MAX_LPC_ORDER];
816
    int32_t *res, *smp;
817

    
818
    frame = &ctx->frame;
819
    sub = &frame->subframes[ch];
820
    res = sub->residual;
821
    smp = sub->samples;
822
    n = frame->blocksize;
823

    
824
    /* CONSTANT */
825
    for(i=1; i<n; i++) {
826
        if(smp[i] != smp[0]) break;
827
    }
828
    if(i == n) {
829
        sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
830
        res[0] = smp[0];
831
        return sub->obits;
832
    }
833

    
834
    /* VERBATIM */
835
    if(n < 5) {
836
        sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
837
        encode_residual_verbatim(res, smp, n);
838
        return sub->obits * n;
839
    }
840

    
841
    min_order = ctx->options.min_prediction_order;
842
    max_order = ctx->options.max_prediction_order;
843
    min_porder = ctx->options.min_partition_order;
844
    max_porder = ctx->options.max_partition_order;
845
    precision = ctx->options.lpc_coeff_precision;
846
    omethod = ctx->options.prediction_order_method;
847

    
848
    /* FIXED */
849
    if(!ctx->options.use_lpc || max_order == 0 || (n <= max_order)) {
850
        uint32_t bits[MAX_FIXED_ORDER+1];
851
        if(max_order > MAX_FIXED_ORDER) max_order = MAX_FIXED_ORDER;
852
        opt_order = 0;
853
        bits[0] = UINT32_MAX;
854
        for(i=min_order; i<=max_order; i++) {
855
            encode_residual_fixed(res, smp, n, i);
856
            bits[i] = calc_rice_params_fixed(&sub->rc, min_porder, max_porder, res,
857
                                             n, i, sub->obits);
858
            if(bits[i] < bits[opt_order]) {
859
                opt_order = i;
860
            }
861
        }
862
        sub->order = opt_order;
863
        sub->type = FLAC_SUBFRAME_FIXED;
864
        sub->type_code = sub->type | sub->order;
865
        if(sub->order != max_order) {
866
            encode_residual_fixed(res, smp, n, sub->order);
867
            return calc_rice_params_fixed(&sub->rc, min_porder, max_porder, res, n,
868
                                          sub->order, sub->obits);
869
        }
870
        return bits[sub->order];
871
    }
872

    
873
    /* LPC */
874
    opt_order = ff_lpc_calc_coefs(&ctx->dsp, smp, n, min_order, max_order,
875
                                  precision, coefs, shift, ctx->options.use_lpc,
876
                                  omethod, MAX_LPC_SHIFT, 0);
877

    
878
    if(omethod == ORDER_METHOD_2LEVEL ||
879
       omethod == ORDER_METHOD_4LEVEL ||
880
       omethod == ORDER_METHOD_8LEVEL) {
881
        int levels = 1 << omethod;
882
        uint32_t bits[levels];
883
        int order;
884
        int opt_index = levels-1;
885
        opt_order = max_order-1;
886
        bits[opt_index] = UINT32_MAX;
887
        for(i=levels-1; i>=0; i--) {
888
            order = min_order + (((max_order-min_order+1) * (i+1)) / levels)-1;
889
            if(order < 0) order = 0;
890
            encode_residual_lpc(res, smp, n, order+1, coefs[order], shift[order]);
891
            bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
892
                                           res, n, order+1, sub->obits, precision);
893
            if(bits[i] < bits[opt_index]) {
894
                opt_index = i;
895
                opt_order = order;
896
            }
897
        }
898
        opt_order++;
899
    } else if(omethod == ORDER_METHOD_SEARCH) {
900
        // brute-force optimal order search
901
        uint32_t bits[MAX_LPC_ORDER];
902
        opt_order = 0;
903
        bits[0] = UINT32_MAX;
904
        for(i=min_order-1; i<max_order; i++) {
905
            encode_residual_lpc(res, smp, n, i+1, coefs[i], shift[i]);
906
            bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
907
                                           res, n, i+1, sub->obits, precision);
908
            if(bits[i] < bits[opt_order]) {
909
                opt_order = i;
910
            }
911
        }
912
        opt_order++;
913
    } else if(omethod == ORDER_METHOD_LOG) {
914
        uint32_t bits[MAX_LPC_ORDER];
915
        int step;
916

    
917
        opt_order= min_order - 1 + (max_order-min_order)/3;
918
        memset(bits, -1, sizeof(bits));
919

    
920
        for(step=16 ;step; step>>=1){
921
            int last= opt_order;
922
            for(i=last-step; i<=last+step; i+= step){
923
                if(i<min_order-1 || i>=max_order || bits[i] < UINT32_MAX)
924
                    continue;
925
                encode_residual_lpc(res, smp, n, i+1, coefs[i], shift[i]);
926
                bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
927
                                            res, n, i+1, sub->obits, precision);
928
                if(bits[i] < bits[opt_order])
929
                    opt_order= i;
930
            }
931
        }
932
        opt_order++;
933
    }
934

    
935
    sub->order = opt_order;
936
    sub->type = FLAC_SUBFRAME_LPC;
937
    sub->type_code = sub->type | (sub->order-1);
938
    sub->shift = shift[sub->order-1];
939
    for(i=0; i<sub->order; i++) {
940
        sub->coefs[i] = coefs[sub->order-1][i];
941
    }
942
    encode_residual_lpc(res, smp, n, sub->order, sub->coefs, sub->shift);
943
    return calc_rice_params_lpc(&sub->rc, min_porder, max_porder, res, n, sub->order,
944
                                sub->obits, precision);
945
}
946

    
947
static int encode_residual_v(FlacEncodeContext *ctx, int ch)
948
{
949
    int i, n;
950
    FlacFrame *frame;
951
    FlacSubframe *sub;
952
    int32_t *res, *smp;
953

    
954
    frame = &ctx->frame;
955
    sub = &frame->subframes[ch];
956
    res = sub->residual;
957
    smp = sub->samples;
958
    n = frame->blocksize;
959

    
960
    /* CONSTANT */
961
    for(i=1; i<n; i++) {
962
        if(smp[i] != smp[0]) break;
963
    }
964
    if(i == n) {
965
        sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
966
        res[0] = smp[0];
967
        return sub->obits;
968
    }
969

    
970
    /* VERBATIM */
971
    sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
972
    encode_residual_verbatim(res, smp, n);
973
    return sub->obits * n;
974
}
975

    
976
static int estimate_stereo_mode(int32_t *left_ch, int32_t *right_ch, int n)
977
{
978
    int i, best;
979
    int32_t lt, rt;
980
    uint64_t sum[4];
981
    uint64_t score[4];
982
    int k;
983

    
984
    /* calculate sum of 2nd order residual for each channel */
985
    sum[0] = sum[1] = sum[2] = sum[3] = 0;
986
    for(i=2; i<n; i++) {
987
        lt = left_ch[i] - 2*left_ch[i-1] + left_ch[i-2];
988
        rt = right_ch[i] - 2*right_ch[i-1] + right_ch[i-2];
989
        sum[2] += FFABS((lt + rt) >> 1);
990
        sum[3] += FFABS(lt - rt);
991
        sum[0] += FFABS(lt);
992
        sum[1] += FFABS(rt);
993
    }
994
    /* estimate bit counts */
995
    for(i=0; i<4; i++) {
996
        k = find_optimal_param(2*sum[i], n);
997
        sum[i] = rice_encode_count(2*sum[i], n, k);
998
    }
999

    
1000
    /* calculate score for each mode */
1001
    score[0] = sum[0] + sum[1];
1002
    score[1] = sum[0] + sum[3];
1003
    score[2] = sum[1] + sum[3];
1004
    score[3] = sum[2] + sum[3];
1005

    
1006
    /* return mode with lowest score */
1007
    best = 0;
1008
    for(i=1; i<4; i++) {
1009
        if(score[i] < score[best]) {
1010
            best = i;
1011
        }
1012
    }
1013
    if(best == 0) {
1014
        return FLAC_CHMODE_LEFT_RIGHT;
1015
    } else if(best == 1) {
1016
        return FLAC_CHMODE_LEFT_SIDE;
1017
    } else if(best == 2) {
1018
        return FLAC_CHMODE_RIGHT_SIDE;
1019
    } else {
1020
        return FLAC_CHMODE_MID_SIDE;
1021
    }
1022
}
1023

    
1024
/**
1025
 * Perform stereo channel decorrelation
1026
 */
1027
static void channel_decorrelation(FlacEncodeContext *ctx)
1028
{
1029
    FlacFrame *frame;
1030
    int32_t *left, *right;
1031
    int i, n;
1032

    
1033
    frame = &ctx->frame;
1034
    n = frame->blocksize;
1035
    left  = frame->subframes[0].samples;
1036
    right = frame->subframes[1].samples;
1037

    
1038
    if(ctx->channels != 2) {
1039
        frame->ch_mode = FLAC_CHMODE_NOT_STEREO;
1040
        return;
1041
    }
1042

    
1043
    frame->ch_mode = estimate_stereo_mode(left, right, n);
1044

    
1045
    /* perform decorrelation and adjust bits-per-sample */
1046
    if(frame->ch_mode == FLAC_CHMODE_LEFT_RIGHT) {
1047
        return;
1048
    }
1049
    if(frame->ch_mode == FLAC_CHMODE_MID_SIDE) {
1050
        int32_t tmp;
1051
        for(i=0; i<n; i++) {
1052
            tmp = left[i];
1053
            left[i] = (tmp + right[i]) >> 1;
1054
            right[i] = tmp - right[i];
1055
        }
1056
        frame->subframes[1].obits++;
1057
    } else if(frame->ch_mode == FLAC_CHMODE_LEFT_SIDE) {
1058
        for(i=0; i<n; i++) {
1059
            right[i] = left[i] - right[i];
1060
        }
1061
        frame->subframes[1].obits++;
1062
    } else {
1063
        for(i=0; i<n; i++) {
1064
            left[i] -= right[i];
1065
        }
1066
        frame->subframes[0].obits++;
1067
    }
1068
}
1069

    
1070
static void write_utf8(PutBitContext *pb, uint32_t val)
1071
{
1072
    uint8_t tmp;
1073
    PUT_UTF8(val, tmp, put_bits(pb, 8, tmp);)
1074
}
1075

    
1076
static void output_frame_header(FlacEncodeContext *s)
1077
{
1078
    FlacFrame *frame;
1079
    int crc;
1080

    
1081
    frame = &s->frame;
1082

    
1083
    put_bits(&s->pb, 16, 0xFFF8);
1084
    put_bits(&s->pb, 4, frame->bs_code[0]);
1085
    put_bits(&s->pb, 4, s->sr_code[0]);
1086
    if(frame->ch_mode == FLAC_CHMODE_NOT_STEREO) {
1087
        put_bits(&s->pb, 4, s->ch_code);
1088
    } else {
1089
        put_bits(&s->pb, 4, frame->ch_mode);
1090
    }
1091
    put_bits(&s->pb, 3, 4); /* bits-per-sample code */
1092
    put_bits(&s->pb, 1, 0);
1093
    write_utf8(&s->pb, s->frame_count);
1094
    if(frame->bs_code[0] == 6) {
1095
        put_bits(&s->pb, 8, frame->bs_code[1]);
1096
    } else if(frame->bs_code[0] == 7) {
1097
        put_bits(&s->pb, 16, frame->bs_code[1]);
1098
    }
1099
    if(s->sr_code[0] == 12) {
1100
        put_bits(&s->pb, 8, s->sr_code[1]);
1101
    } else if(s->sr_code[0] > 12) {
1102
        put_bits(&s->pb, 16, s->sr_code[1]);
1103
    }
1104
    flush_put_bits(&s->pb);
1105
    crc = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
1106
                 s->pb.buf, put_bits_count(&s->pb)>>3);
1107
    put_bits(&s->pb, 8, crc);
1108
}
1109

    
1110
static void output_subframe_constant(FlacEncodeContext *s, int ch)
1111
{
1112
    FlacSubframe *sub;
1113
    int32_t res;
1114

    
1115
    sub = &s->frame.subframes[ch];
1116
    res = sub->residual[0];
1117
    put_sbits(&s->pb, sub->obits, res);
1118
}
1119

    
1120
static void output_subframe_verbatim(FlacEncodeContext *s, int ch)
1121
{
1122
    int i;
1123
    FlacFrame *frame;
1124
    FlacSubframe *sub;
1125
    int32_t res;
1126

    
1127
    frame = &s->frame;
1128
    sub = &frame->subframes[ch];
1129

    
1130
    for(i=0; i<frame->blocksize; i++) {
1131
        res = sub->residual[i];
1132
        put_sbits(&s->pb, sub->obits, res);
1133
    }
1134
}
1135

    
1136
static void output_residual(FlacEncodeContext *ctx, int ch)
1137
{
1138
    int i, j, p, n, parts;
1139
    int k, porder, psize, res_cnt;
1140
    FlacFrame *frame;
1141
    FlacSubframe *sub;
1142
    int32_t *res;
1143

    
1144
    frame = &ctx->frame;
1145
    sub = &frame->subframes[ch];
1146
    res = sub->residual;
1147
    n = frame->blocksize;
1148

    
1149
    /* rice-encoded block */
1150
    put_bits(&ctx->pb, 2, 0);
1151

    
1152
    /* partition order */
1153
    porder = sub->rc.porder;
1154
    psize = n >> porder;
1155
    parts = (1 << porder);
1156
    put_bits(&ctx->pb, 4, porder);
1157
    res_cnt = psize - sub->order;
1158

    
1159
    /* residual */
1160
    j = sub->order;
1161
    for(p=0; p<parts; p++) {
1162
        k = sub->rc.params[p];
1163
        put_bits(&ctx->pb, 4, k);
1164
        if(p == 1) res_cnt = psize;
1165
        for(i=0; i<res_cnt && j<n; i++, j++) {
1166
            set_sr_golomb_flac(&ctx->pb, res[j], k, INT32_MAX, 0);
1167
        }
1168
    }
1169
}
1170

    
1171
static void output_subframe_fixed(FlacEncodeContext *ctx, int ch)
1172
{
1173
    int i;
1174
    FlacFrame *frame;
1175
    FlacSubframe *sub;
1176

    
1177
    frame = &ctx->frame;
1178
    sub = &frame->subframes[ch];
1179

    
1180
    /* warm-up samples */
1181
    for(i=0; i<sub->order; i++) {
1182
        put_sbits(&ctx->pb, sub->obits, sub->residual[i]);
1183
    }
1184

    
1185
    /* residual */
1186
    output_residual(ctx, ch);
1187
}
1188

    
1189
static void output_subframe_lpc(FlacEncodeContext *ctx, int ch)
1190
{
1191
    int i, cbits;
1192
    FlacFrame *frame;
1193
    FlacSubframe *sub;
1194

    
1195
    frame = &ctx->frame;
1196
    sub = &frame->subframes[ch];
1197

    
1198
    /* warm-up samples */
1199
    for(i=0; i<sub->order; i++) {
1200
        put_sbits(&ctx->pb, sub->obits, sub->residual[i]);
1201
    }
1202

    
1203
    /* LPC coefficients */
1204
    cbits = ctx->options.lpc_coeff_precision;
1205
    put_bits(&ctx->pb, 4, cbits-1);
1206
    put_sbits(&ctx->pb, 5, sub->shift);
1207
    for(i=0; i<sub->order; i++) {
1208
        put_sbits(&ctx->pb, cbits, sub->coefs[i]);
1209
    }
1210

    
1211
    /* residual */
1212
    output_residual(ctx, ch);
1213
}
1214

    
1215
static void output_subframes(FlacEncodeContext *s)
1216
{
1217
    FlacFrame *frame;
1218
    FlacSubframe *sub;
1219
    int ch;
1220

    
1221
    frame = &s->frame;
1222

    
1223
    for(ch=0; ch<s->channels; ch++) {
1224
        sub = &frame->subframes[ch];
1225

    
1226
        /* subframe header */
1227
        put_bits(&s->pb, 1, 0);
1228
        put_bits(&s->pb, 6, sub->type_code);
1229
        put_bits(&s->pb, 1, 0); /* no wasted bits */
1230

    
1231
        /* subframe */
1232
        if(sub->type == FLAC_SUBFRAME_CONSTANT) {
1233
            output_subframe_constant(s, ch);
1234
        } else if(sub->type == FLAC_SUBFRAME_VERBATIM) {
1235
            output_subframe_verbatim(s, ch);
1236
        } else if(sub->type == FLAC_SUBFRAME_FIXED) {
1237
            output_subframe_fixed(s, ch);
1238
        } else if(sub->type == FLAC_SUBFRAME_LPC) {
1239
            output_subframe_lpc(s, ch);
1240
        }
1241
    }
1242
}
1243

    
1244
static void output_frame_footer(FlacEncodeContext *s)
1245
{
1246
    int crc;
1247
    flush_put_bits(&s->pb);
1248
    crc = bswap_16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
1249
                          s->pb.buf, put_bits_count(&s->pb)>>3));
1250
    put_bits(&s->pb, 16, crc);
1251
    flush_put_bits(&s->pb);
1252
}
1253

    
1254
static void update_md5_sum(FlacEncodeContext *s, int16_t *samples)
1255
{
1256
#ifdef WORDS_BIGENDIAN
1257
    int i;
1258
    for(i = 0; i < s->frame.blocksize*s->channels; i++) {
1259
        int16_t smp = le2me_16(samples[i]);
1260
        av_md5_update(s->md5ctx, (uint8_t *)&smp, 2);
1261
    }
1262
#else
1263
    av_md5_update(s->md5ctx, (uint8_t *)samples, s->frame.blocksize*s->channels*2);
1264
#endif
1265
}
1266

    
1267
static int flac_encode_frame(AVCodecContext *avctx, uint8_t *frame,
1268
                             int buf_size, void *data)
1269
{
1270
    int ch;
1271
    FlacEncodeContext *s;
1272
    int16_t *samples = data;
1273
    int out_bytes;
1274
    int reencoded=0;
1275

    
1276
    s = avctx->priv_data;
1277

    
1278
    if(buf_size < s->max_framesize*2) {
1279
        av_log(avctx, AV_LOG_ERROR, "output buffer too small\n");
1280
        return 0;
1281
    }
1282

    
1283
    /* when the last block is reached, update the header in extradata */
1284
    if (!data) {
1285
        s->min_framesize = s->min_encoded_framesize;
1286
        s->max_framesize = s->max_encoded_framesize;
1287
        av_md5_final(s->md5ctx, s->md5sum);
1288
        write_streaminfo(s, avctx->extradata);
1289
        return 0;
1290
    }
1291

    
1292
    init_frame(s);
1293

    
1294
    copy_samples(s, samples);
1295

    
1296
    channel_decorrelation(s);
1297

    
1298
    for(ch=0; ch<s->channels; ch++) {
1299
        encode_residual(s, ch);
1300
    }
1301

    
1302
write_frame:
1303
    init_put_bits(&s->pb, frame, buf_size);
1304
    output_frame_header(s);
1305
    output_subframes(s);
1306
    output_frame_footer(s);
1307
    out_bytes = put_bits_count(&s->pb) >> 3;
1308

    
1309
    if(out_bytes > s->max_framesize) {
1310
        if(reencoded) {
1311
            /* still too large. must be an error. */
1312
            av_log(avctx, AV_LOG_ERROR, "error encoding frame\n");
1313
            return -1;
1314
        }
1315

    
1316
        /* frame too large. use verbatim mode */
1317
        for(ch=0; ch<s->channels; ch++) {
1318
            encode_residual_v(s, ch);
1319
        }
1320
        reencoded = 1;
1321
        goto write_frame;
1322
    }
1323

    
1324
    s->frame_count++;
1325
    s->sample_count += avctx->frame_size;
1326
    update_md5_sum(s, samples);
1327
    if (out_bytes > s->max_encoded_framesize)
1328
        s->max_encoded_framesize = out_bytes;
1329
    if (out_bytes < s->min_encoded_framesize)
1330
        s->min_encoded_framesize = out_bytes;
1331

    
1332
    return out_bytes;
1333
}
1334

    
1335
static av_cold int flac_encode_close(AVCodecContext *avctx)
1336
{
1337
    if (avctx->priv_data) {
1338
        FlacEncodeContext *s = avctx->priv_data;
1339
        av_freep(&s->md5ctx);
1340
    }
1341
    av_freep(&avctx->extradata);
1342
    avctx->extradata_size = 0;
1343
    av_freep(&avctx->coded_frame);
1344
    return 0;
1345
}
1346

    
1347
AVCodec flac_encoder = {
1348
    "flac",
1349
    CODEC_TYPE_AUDIO,
1350
    CODEC_ID_FLAC,
1351
    sizeof(FlacEncodeContext),
1352
    flac_encode_init,
1353
    flac_encode_frame,
1354
    flac_encode_close,
1355
    NULL,
1356
    .capabilities = CODEC_CAP_SMALL_LAST_FRAME | CODEC_CAP_DELAY,
1357
    .sample_fmts = (enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
1358
    .long_name = NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),
1359
};