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1
/**
2
 * FLAC audio encoder
3
 * Copyright (c) 2006  Justin Ruggles <jruggle@earthlink.net>
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.
11
 *
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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
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 */
21

    
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#include "avcodec.h"
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#include "bitstream.h"
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#include "crc.h"
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#include "dsputil.h"
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#include "golomb.h"
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#include "lls.h"
28

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

    
33
#define FLAC_SUBFRAME_CONSTANT  0
34
#define FLAC_SUBFRAME_VERBATIM  1
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#define FLAC_SUBFRAME_FIXED     8
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#define FLAC_SUBFRAME_LPC      32
37

    
38
#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
43

    
44
#define ORDER_METHOD_EST     0
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#define ORDER_METHOD_2LEVEL  1
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#define ORDER_METHOD_4LEVEL  2
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#define ORDER_METHOD_8LEVEL  3
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#define ORDER_METHOD_SEARCH  4
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#define ORDER_METHOD_LOG     5
50

    
51
#define FLAC_STREAMINFO_SIZE  34
52

    
53
#define MIN_LPC_ORDER       1
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#define MAX_LPC_ORDER      32
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#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)
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#define MAX_LPC_PRECISION  15
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#define MAX_LPC_SHIFT      15
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#define MAX_RICE_PARAM     14
61

    
62
typedef struct CompressionOptions {
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    int compression_level;
64
    int block_time_ms;
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    int use_lpc;
66
    int lpc_coeff_precision;
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    int min_prediction_order;
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    int max_prediction_order;
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    int prediction_order_method;
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    int min_partition_order;
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    int max_partition_order;
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} CompressionOptions;
73

    
74
typedef struct RiceContext {
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    int porder;
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    int params[MAX_PARTITIONS];
77
} RiceContext;
78

    
79
typedef struct FlacSubframe {
80
    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;
86
    RiceContext rc;
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    int32_t samples[FLAC_MAX_BLOCKSIZE];
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    int32_t residual[FLAC_MAX_BLOCKSIZE+1];
89
} FlacSubframe;
90

    
91
typedef struct FlacFrame {
92
    FlacSubframe subframes[FLAC_MAX_CH];
93
    int blocksize;
94
    int bs_code[2];
95
    uint8_t crc8;
96
    int ch_mode;
97
} FlacFrame;
98

    
99
typedef struct FlacEncodeContext {
100
    PutBitContext pb;
101
    int channels;
102
    int ch_code;
103
    int samplerate;
104
    int sr_code[2];
105
    int blocksize;
106
    int max_framesize;
107
    uint32_t frame_count;
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    FlacFrame frame;
109
    CompressionOptions options;
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    AVCodecContext *avctx;
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    DSPContext dsp;
112
} FlacEncodeContext;
113

    
114
static const int flac_samplerates[16] = {
115
    0, 0, 0, 0,
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    8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
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    0, 0, 0, 0
118
};
119

    
120
static const int flac_blocksizes[16] = {
121
    0,
122
    192,
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    576, 1152, 2304, 4608,
124
    0, 0,
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    256, 512, 1024, 2048, 4096, 8192, 16384, 32768
126
};
127

    
128
/**
129
 * Writes streaminfo metadata block to byte array
130
 */
131
static void write_streaminfo(FlacEncodeContext *s, uint8_t *header)
132
{
133
    PutBitContext pb;
134

    
135
    memset(header, 0, FLAC_STREAMINFO_SIZE);
136
    init_put_bits(&pb, header, FLAC_STREAMINFO_SIZE);
137

    
138
    /* streaminfo metadata block */
139
    put_bits(&pb, 16, s->blocksize);
140
    put_bits(&pb, 16, s->blocksize);
141
    put_bits(&pb, 24, 0);
142
    put_bits(&pb, 24, s->max_framesize);
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    put_bits(&pb, 20, s->samplerate);
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    put_bits(&pb, 3, s->channels-1);
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    put_bits(&pb, 5, 15);       /* bits per sample - 1 */
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    flush_put_bits(&pb);
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    /* total samples = 0 */
148
    /* MD5 signature = 0 */
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
}
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172
static 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,
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                                                   ORDER_METHOD_EST,    ORDER_METHOD_EST,    ORDER_METHOD_EST,
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                                                   ORDER_METHOD_4LEVEL, ORDER_METHOD_LOG,    ORDER_METHOD_4LEVEL,
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                                                   ORDER_METHOD_LOG,    ORDER_METHOD_SEARCH, ORDER_METHOD_LOG,
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                                                   ORDER_METHOD_SEARCH})[level];
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    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
        s->blocksize = avctx->frame_size;
355
    } else {
356
        s->blocksize = select_blocksize(s->samplerate, s->options.block_time_ms);
357
        avctx->frame_size = s->blocksize;
358
    }
359
    av_log(avctx, AV_LOG_DEBUG, " block size: %d\n", s->blocksize);
360

    
361
    /* set LPC precision */
362
    if(avctx->lpc_coeff_precision > 0) {
363
        if(avctx->lpc_coeff_precision > MAX_LPC_PRECISION) {
364
            av_log(avctx, AV_LOG_ERROR, "invalid lpc coeff precision: %d\n",
365
                   avctx->lpc_coeff_precision);
366
            return -1;
367
        }
368
        s->options.lpc_coeff_precision = avctx->lpc_coeff_precision;
369
    } else {
370
        /* select LPC precision based on block size */
371
        if(     s->blocksize <=   192) s->options.lpc_coeff_precision =  7;
372
        else if(s->blocksize <=   384) s->options.lpc_coeff_precision =  8;
373
        else if(s->blocksize <=   576) s->options.lpc_coeff_precision =  9;
374
        else if(s->blocksize <=  1152) s->options.lpc_coeff_precision = 10;
375
        else if(s->blocksize <=  2304) s->options.lpc_coeff_precision = 11;
376
        else if(s->blocksize <=  4608) s->options.lpc_coeff_precision = 12;
377
        else if(s->blocksize <=  8192) s->options.lpc_coeff_precision = 13;
378
        else if(s->blocksize <= 16384) s->options.lpc_coeff_precision = 14;
379
        else                           s->options.lpc_coeff_precision = 15;
380
    }
381
    av_log(avctx, AV_LOG_DEBUG, " lpc precision: %d\n",
382
           s->options.lpc_coeff_precision);
383

    
384
    /* set maximum encoded frame size in verbatim mode */
385
    if(s->channels == 2) {
386
        s->max_framesize = 14 + ((s->blocksize * 33 + 7) >> 3);
387
    } else {
388
        s->max_framesize = 14 + (s->blocksize * s->channels * 2);
389
    }
390

    
391
    streaminfo = av_malloc(FLAC_STREAMINFO_SIZE);
392
    write_streaminfo(s, streaminfo);
393
    avctx->extradata = streaminfo;
394
    avctx->extradata_size = FLAC_STREAMINFO_SIZE;
395

    
396
    s->frame_count = 0;
397

    
398
    avctx->coded_frame = avcodec_alloc_frame();
399
    avctx->coded_frame->key_frame = 1;
400

    
401
    return 0;
402
}
403

    
404
static void init_frame(FlacEncodeContext *s)
405
{
406
    int i, ch;
407
    FlacFrame *frame;
408

    
409
    frame = &s->frame;
410

    
411
    for(i=0; i<16; i++) {
412
        if(s->blocksize == flac_blocksizes[i]) {
413
            frame->blocksize = flac_blocksizes[i];
414
            frame->bs_code[0] = i;
415
            frame->bs_code[1] = 0;
416
            break;
417
        }
418
    }
419
    if(i == 16) {
420
        frame->blocksize = s->blocksize;
421
        if(frame->blocksize <= 256) {
422
            frame->bs_code[0] = 6;
423
            frame->bs_code[1] = frame->blocksize-1;
424
        } else {
425
            frame->bs_code[0] = 7;
426
            frame->bs_code[1] = frame->blocksize-1;
427
        }
428
    }
429

    
430
    for(ch=0; ch<s->channels; ch++) {
431
        frame->subframes[ch].obits = 16;
432
    }
433
}
434

    
435
/**
436
 * Copy channel-interleaved input samples into separate subframes
437
 */
438
static void copy_samples(FlacEncodeContext *s, int16_t *samples)
439
{
440
    int i, j, ch;
441
    FlacFrame *frame;
442

    
443
    frame = &s->frame;
444
    for(i=0,j=0; i<frame->blocksize; i++) {
445
        for(ch=0; ch<s->channels; ch++,j++) {
446
            frame->subframes[ch].samples[i] = samples[j];
447
        }
448
    }
449
}
450

    
451

    
452
#define rice_encode_count(sum, n, k) (((n)*((k)+1))+((sum-(n>>1))>>(k)))
453

    
454
/**
455
 * Solve for d/dk(rice_encode_count) = n-((sum-(n>>1))>>(k+1)) = 0
456
 */
457
static int find_optimal_param(uint32_t sum, int n)
458
{
459
    int k;
460
    uint32_t sum2;
461

    
462
    if(sum <= n>>1)
463
        return 0;
464
    sum2 = sum-(n>>1);
465
    k = av_log2(n<256 ? FASTDIV(sum2,n) : sum2/n);
466
    return FFMIN(k, MAX_RICE_PARAM);
467
}
468

    
469
static uint32_t calc_optimal_rice_params(RiceContext *rc, int porder,
470
                                         uint32_t *sums, int n, int pred_order)
471
{
472
    int i;
473
    int k, cnt, part;
474
    uint32_t all_bits;
475

    
476
    part = (1 << porder);
477
    all_bits = 4 * part;
478

    
479
    cnt = (n >> porder) - pred_order;
480
    for(i=0; i<part; i++) {
481
        k = find_optimal_param(sums[i], cnt);
482
        rc->params[i] = k;
483
        all_bits += rice_encode_count(sums[i], cnt, k);
484
        cnt = n >> porder;
485
    }
486

    
487
    rc->porder = porder;
488

    
489
    return all_bits;
490
}
491

    
492
static void calc_sums(int pmin, int pmax, uint32_t *data, int n, int pred_order,
493
                      uint32_t sums[][MAX_PARTITIONS])
494
{
495
    int i, j;
496
    int parts;
497
    uint32_t *res, *res_end;
498

    
499
    /* sums for highest level */
500
    parts = (1 << pmax);
501
    res = &data[pred_order];
502
    res_end = &data[n >> pmax];
503
    for(i=0; i<parts; i++) {
504
        uint32_t sum = 0;
505
        while(res < res_end){
506
            sum += *(res++);
507
        }
508
        sums[pmax][i] = sum;
509
        res_end+= n >> pmax;
510
    }
511
    /* sums for lower levels */
512
    for(i=pmax-1; i>=pmin; i--) {
513
        parts = (1 << i);
514
        for(j=0; j<parts; j++) {
515
            sums[i][j] = sums[i+1][2*j] + sums[i+1][2*j+1];
516
        }
517
    }
518
}
519

    
520
static uint32_t calc_rice_params(RiceContext *rc, int pmin, int pmax,
521
                                 int32_t *data, int n, int pred_order)
522
{
523
    int i;
524
    uint32_t bits[MAX_PARTITION_ORDER+1];
525
    int opt_porder;
526
    RiceContext tmp_rc;
527
    uint32_t *udata;
528
    uint32_t sums[MAX_PARTITION_ORDER+1][MAX_PARTITIONS];
529

    
530
    assert(pmin >= 0 && pmin <= MAX_PARTITION_ORDER);
531
    assert(pmax >= 0 && pmax <= MAX_PARTITION_ORDER);
532
    assert(pmin <= pmax);
533

    
534
    udata = av_malloc(n * sizeof(uint32_t));
535
    for(i=0; i<n; i++) {
536
        udata[i] = (2*data[i]) ^ (data[i]>>31);
537
    }
538

    
539
    calc_sums(pmin, pmax, udata, n, pred_order, sums);
540

    
541
    opt_porder = pmin;
542
    bits[pmin] = UINT32_MAX;
543
    for(i=pmin; i<=pmax; i++) {
544
        bits[i] = calc_optimal_rice_params(&tmp_rc, i, sums[i], n, pred_order);
545
        if(bits[i] <= bits[opt_porder]) {
546
            opt_porder = i;
547
            *rc= tmp_rc;
548
        }
549
    }
550

    
551
    av_freep(&udata);
552
    return bits[opt_porder];
553
}
554

    
555
static int get_max_p_order(int max_porder, int n, int order)
556
{
557
    int porder = FFMIN(max_porder, av_log2(n^(n-1)));
558
    if(order > 0)
559
        porder = FFMIN(porder, av_log2(n/order));
560
    return porder;
561
}
562

    
563
static uint32_t calc_rice_params_fixed(RiceContext *rc, int pmin, int pmax,
564
                                       int32_t *data, int n, int pred_order,
565
                                       int bps)
566
{
567
    uint32_t bits;
568
    pmin = get_max_p_order(pmin, n, pred_order);
569
    pmax = get_max_p_order(pmax, n, pred_order);
570
    bits = pred_order*bps + 6;
571
    bits += calc_rice_params(rc, pmin, pmax, data, n, pred_order);
572
    return bits;
573
}
574

    
575
static uint32_t calc_rice_params_lpc(RiceContext *rc, int pmin, int pmax,
576
                                     int32_t *data, int n, int pred_order,
577
                                     int bps, int precision)
578
{
579
    uint32_t bits;
580
    pmin = get_max_p_order(pmin, n, pred_order);
581
    pmax = get_max_p_order(pmax, n, pred_order);
582
    bits = pred_order*bps + 4 + 5 + pred_order*precision + 6;
583
    bits += calc_rice_params(rc, pmin, pmax, data, n, pred_order);
584
    return bits;
585
}
586

    
587
/**
588
 * Apply Welch window function to audio block
589
 */
590
static void apply_welch_window(const int32_t *data, int len, double *w_data)
591
{
592
    int i, n2;
593
    double w;
594
    double c;
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
 * Levinson-Durbin recursion.
648
 * Produces LPC coefficients from autocorrelation data.
649
 */
650
static void compute_lpc_coefs(const double *autoc, int max_order,
651
                              double lpc[][MAX_LPC_ORDER], double *ref)
652
{
653
   int i, j, i2;
654
   double r, err, tmp;
655
   double lpc_tmp[MAX_LPC_ORDER];
656

    
657
   for(i=0; i<max_order; i++) lpc_tmp[i] = 0;
658
   err = autoc[0];
659

    
660
   for(i=0; i<max_order; i++) {
661
      r = -autoc[i+1];
662
      for(j=0; j<i; j++) {
663
          r -= lpc_tmp[j] * autoc[i-j];
664
      }
665
      r /= err;
666
      ref[i] = fabs(r);
667

    
668
      err *= 1.0 - (r * r);
669

    
670
      i2 = (i >> 1);
671
      lpc_tmp[i] = r;
672
      for(j=0; j<i2; j++) {
673
         tmp = lpc_tmp[j];
674
         lpc_tmp[j] += r * lpc_tmp[i-1-j];
675
         lpc_tmp[i-1-j] += r * tmp;
676
      }
677
      if(i & 1) {
678
          lpc_tmp[j] += lpc_tmp[j] * r;
679
      }
680

    
681
      for(j=0; j<=i; j++) {
682
          lpc[i][j] = -lpc_tmp[j];
683
      }
684
   }
685
}
686

    
687
/**
688
 * Quantize LPC coefficients
689
 */
690
static void quantize_lpc_coefs(double *lpc_in, int order, int precision,
691
                               int32_t *lpc_out, int *shift)
692
{
693
    int i;
694
    double cmax, error;
695
    int32_t qmax;
696
    int sh;
697

    
698
    /* define maximum levels */
699
    qmax = (1 << (precision - 1)) - 1;
700

    
701
    /* find maximum coefficient value */
702
    cmax = 0.0;
703
    for(i=0; i<order; i++) {
704
        cmax= FFMAX(cmax, fabs(lpc_in[i]));
705
    }
706

    
707
    /* if maximum value quantizes to zero, return all zeros */
708
    if(cmax * (1 << MAX_LPC_SHIFT) < 1.0) {
709
        *shift = 0;
710
        memset(lpc_out, 0, sizeof(int32_t) * order);
711
        return;
712
    }
713

    
714
    /* calculate level shift which scales max coeff to available bits */
715
    sh = MAX_LPC_SHIFT;
716
    while((cmax * (1 << sh) > qmax) && (sh > 0)) {
717
        sh--;
718
    }
719

    
720
    /* since negative shift values are unsupported in decoder, scale down
721
       coefficients instead */
722
    if(sh == 0 && cmax > qmax) {
723
        double scale = ((double)qmax) / cmax;
724
        for(i=0; i<order; i++) {
725
            lpc_in[i] *= scale;
726
        }
727
    }
728

    
729
    /* output quantized coefficients and level shift */
730
    error=0;
731
    for(i=0; i<order; i++) {
732
        error += lpc_in[i] * (1 << sh);
733
        lpc_out[i] = av_clip(lrintf(error), -qmax, qmax);
734
        error -= lpc_out[i];
735
    }
736
    *shift = sh;
737
}
738

    
739
static int estimate_best_order(double *ref, int max_order)
740
{
741
    int i, est;
742

    
743
    est = 1;
744
    for(i=max_order-1; i>=0; i--) {
745
        if(ref[i] > 0.10) {
746
            est = i+1;
747
            break;
748
        }
749
    }
750
    return est;
751
}
752

    
753
/**
754
 * Calculate LPC coefficients for multiple orders
755
 */
756
static int lpc_calc_coefs(FlacEncodeContext *s,
757
                          const int32_t *samples, int blocksize, int max_order,
758
                          int precision, int32_t coefs[][MAX_LPC_ORDER],
759
                          int *shift, int use_lpc, int omethod)
760
{
761
    double autoc[MAX_LPC_ORDER+1];
762
    double ref[MAX_LPC_ORDER];
763
    double lpc[MAX_LPC_ORDER][MAX_LPC_ORDER];
764
    int i, j, pass;
765
    int opt_order;
766

    
767
    assert(max_order >= MIN_LPC_ORDER && max_order <= MAX_LPC_ORDER);
768

    
769
    if(use_lpc == 1){
770
        s->dsp.flac_compute_autocorr(samples, blocksize, max_order, autoc);
771

    
772
        compute_lpc_coefs(autoc, max_order, lpc, ref);
773
    }else{
774
        LLSModel m[2];
775
        double var[MAX_LPC_ORDER+1], weight;
776

    
777
        for(pass=0; pass<use_lpc-1; pass++){
778
            av_init_lls(&m[pass&1], max_order);
779

    
780
            weight=0;
781
            for(i=max_order; i<blocksize; i++){
782
                for(j=0; j<=max_order; j++)
783
                    var[j]= samples[i-j];
784

    
785
                if(pass){
786
                    double eval, inv, rinv;
787
                    eval= av_evaluate_lls(&m[(pass-1)&1], var+1, max_order-1);
788
                    eval= (512>>pass) + fabs(eval - var[0]);
789
                    inv = 1/eval;
790
                    rinv = sqrt(inv);
791
                    for(j=0; j<=max_order; j++)
792
                        var[j] *= rinv;
793
                    weight += inv;
794
                }else
795
                    weight++;
796

    
797
                av_update_lls(&m[pass&1], var, 1.0);
798
            }
799
            av_solve_lls(&m[pass&1], 0.001, 0);
800
        }
801

    
802
        for(i=0; i<max_order; i++){
803
            for(j=0; j<max_order; j++)
804
                lpc[i][j]= m[(pass-1)&1].coeff[i][j];
805
            ref[i]= sqrt(m[(pass-1)&1].variance[i] / weight) * (blocksize - max_order) / 4000;
806
        }
807
        for(i=max_order-1; i>0; i--)
808
            ref[i] = ref[i-1] - ref[i];
809
    }
810
    opt_order = max_order;
811

    
812
    if(omethod == ORDER_METHOD_EST) {
813
        opt_order = estimate_best_order(ref, max_order);
814
        i = opt_order-1;
815
        quantize_lpc_coefs(lpc[i], i+1, precision, coefs[i], &shift[i]);
816
    } else {
817
        for(i=0; i<max_order; i++) {
818
            quantize_lpc_coefs(lpc[i], i+1, precision, coefs[i], &shift[i]);
819
        }
820
    }
821

    
822
    return opt_order;
823
}
824

    
825

    
826
static void encode_residual_verbatim(int32_t *res, int32_t *smp, int n)
827
{
828
    assert(n > 0);
829
    memcpy(res, smp, n * sizeof(int32_t));
830
}
831

    
832
static void encode_residual_fixed(int32_t *res, const int32_t *smp, int n,
833
                                  int order)
834
{
835
    int i;
836

    
837
    for(i=0; i<order; i++) {
838
        res[i] = smp[i];
839
    }
840

    
841
    if(order==0){
842
        for(i=order; i<n; i++)
843
            res[i]= smp[i];
844
    }else if(order==1){
845
        for(i=order; i<n; i++)
846
            res[i]= smp[i] - smp[i-1];
847
    }else if(order==2){
848
        int a = smp[order-1] - smp[order-2];
849
        for(i=order; i<n; i+=2) {
850
            int b = smp[i] - smp[i-1];
851
            res[i]= b - a;
852
            a = smp[i+1] - smp[i];
853
            res[i+1]= a - b;
854
        }
855
    }else if(order==3){
856
        int a = smp[order-1] - smp[order-2];
857
        int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
858
        for(i=order; i<n; i+=2) {
859
            int b = smp[i] - smp[i-1];
860
            int d = b - a;
861
            res[i]= d - c;
862
            a = smp[i+1] - smp[i];
863
            c = a - b;
864
            res[i+1]= c - d;
865
        }
866
    }else{
867
        int a = smp[order-1] - smp[order-2];
868
        int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
869
        int e = smp[order-1] - 3*smp[order-2] + 3*smp[order-3] - smp[order-4];
870
        for(i=order; i<n; i+=2) {
871
            int b = smp[i] - smp[i-1];
872
            int d = b - a;
873
            int f = d - c;
874
            res[i]= f - e;
875
            a = smp[i+1] - smp[i];
876
            c = a - b;
877
            e = c - d;
878
            res[i+1]= e - f;
879
        }
880
    }
881
}
882

    
883
#define LPC1(x) {\
884
    int c = coefs[(x)-1];\
885
    p0 += c*s;\
886
    s = smp[i-(x)+1];\
887
    p1 += c*s;\
888
}
889

    
890
static av_always_inline void encode_residual_lpc_unrolled(
891
    int32_t *res, const int32_t *smp, int n,
892
    int order, const int32_t *coefs, int shift, int big)
893
{
894
    int i;
895
    for(i=order; i<n; i+=2) {
896
        int s = smp[i-order];
897
        int p0 = 0, p1 = 0;
898
        if(big) {
899
            switch(order) {
900
                case 32: LPC1(32)
901
                case 31: LPC1(31)
902
                case 30: LPC1(30)
903
                case 29: LPC1(29)
904
                case 28: LPC1(28)
905
                case 27: LPC1(27)
906
                case 26: LPC1(26)
907
                case 25: LPC1(25)
908
                case 24: LPC1(24)
909
                case 23: LPC1(23)
910
                case 22: LPC1(22)
911
                case 21: LPC1(21)
912
                case 20: LPC1(20)
913
                case 19: LPC1(19)
914
                case 18: LPC1(18)
915
                case 17: LPC1(17)
916
                case 16: LPC1(16)
917
                case 15: LPC1(15)
918
                case 14: LPC1(14)
919
                case 13: LPC1(13)
920
                case 12: LPC1(12)
921
                case 11: LPC1(11)
922
                case 10: LPC1(10)
923
                case  9: LPC1( 9)
924
                         LPC1( 8)
925
                         LPC1( 7)
926
                         LPC1( 6)
927
                         LPC1( 5)
928
                         LPC1( 4)
929
                         LPC1( 3)
930
                         LPC1( 2)
931
                         LPC1( 1)
932
            }
933
        } else {
934
            switch(order) {
935
                case  8: LPC1( 8)
936
                case  7: LPC1( 7)
937
                case  6: LPC1( 6)
938
                case  5: LPC1( 5)
939
                case  4: LPC1( 4)
940
                case  3: LPC1( 3)
941
                case  2: LPC1( 2)
942
                case  1: LPC1( 1)
943
            }
944
        }
945
        res[i  ] = smp[i  ] - (p0 >> shift);
946
        res[i+1] = smp[i+1] - (p1 >> shift);
947
    }
948
}
949

    
950
static void encode_residual_lpc(int32_t *res, const int32_t *smp, int n,
951
                                int order, const int32_t *coefs, int shift)
952
{
953
    int i;
954
    for(i=0; i<order; i++) {
955
        res[i] = smp[i];
956
    }
957
#ifdef CONFIG_SMALL
958
    for(i=order; i<n; i+=2) {
959
        int j;
960
        int s = smp[i];
961
        int p0 = 0, p1 = 0;
962
        for(j=0; j<order; j++) {
963
            int c = coefs[j];
964
            p1 += c*s;
965
            s = smp[i-j-1];
966
            p0 += c*s;
967
        }
968
        res[i  ] = smp[i  ] - (p0 >> shift);
969
        res[i+1] = smp[i+1] - (p1 >> shift);
970
    }
971
#else
972
    switch(order) {
973
        case  1: encode_residual_lpc_unrolled(res, smp, n, 1, coefs, shift, 0); break;
974
        case  2: encode_residual_lpc_unrolled(res, smp, n, 2, coefs, shift, 0); break;
975
        case  3: encode_residual_lpc_unrolled(res, smp, n, 3, coefs, shift, 0); break;
976
        case  4: encode_residual_lpc_unrolled(res, smp, n, 4, coefs, shift, 0); break;
977
        case  5: encode_residual_lpc_unrolled(res, smp, n, 5, coefs, shift, 0); break;
978
        case  6: encode_residual_lpc_unrolled(res, smp, n, 6, coefs, shift, 0); break;
979
        case  7: encode_residual_lpc_unrolled(res, smp, n, 7, coefs, shift, 0); break;
980
        case  8: encode_residual_lpc_unrolled(res, smp, n, 8, coefs, shift, 0); break;
981
        default: encode_residual_lpc_unrolled(res, smp, n, order, coefs, shift, 1); break;
982
    }
983
#endif
984
}
985

    
986
static int encode_residual(FlacEncodeContext *ctx, int ch)
987
{
988
    int i, n;
989
    int min_order, max_order, opt_order, precision, omethod;
990
    int min_porder, max_porder;
991
    FlacFrame *frame;
992
    FlacSubframe *sub;
993
    int32_t coefs[MAX_LPC_ORDER][MAX_LPC_ORDER];
994
    int shift[MAX_LPC_ORDER];
995
    int32_t *res, *smp;
996

    
997
    frame = &ctx->frame;
998
    sub = &frame->subframes[ch];
999
    res = sub->residual;
1000
    smp = sub->samples;
1001
    n = frame->blocksize;
1002

    
1003
    /* CONSTANT */
1004
    for(i=1; i<n; i++) {
1005
        if(smp[i] != smp[0]) break;
1006
    }
1007
    if(i == n) {
1008
        sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
1009
        res[0] = smp[0];
1010
        return sub->obits;
1011
    }
1012

    
1013
    /* VERBATIM */
1014
    if(n < 5) {
1015
        sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
1016
        encode_residual_verbatim(res, smp, n);
1017
        return sub->obits * n;
1018
    }
1019

    
1020
    min_order = ctx->options.min_prediction_order;
1021
    max_order = ctx->options.max_prediction_order;
1022
    min_porder = ctx->options.min_partition_order;
1023
    max_porder = ctx->options.max_partition_order;
1024
    precision = ctx->options.lpc_coeff_precision;
1025
    omethod = ctx->options.prediction_order_method;
1026

    
1027
    /* FIXED */
1028
    if(!ctx->options.use_lpc || max_order == 0 || (n <= max_order)) {
1029
        uint32_t bits[MAX_FIXED_ORDER+1];
1030
        if(max_order > MAX_FIXED_ORDER) max_order = MAX_FIXED_ORDER;
1031
        opt_order = 0;
1032
        bits[0] = UINT32_MAX;
1033
        for(i=min_order; i<=max_order; i++) {
1034
            encode_residual_fixed(res, smp, n, i);
1035
            bits[i] = calc_rice_params_fixed(&sub->rc, min_porder, max_porder, res,
1036
                                             n, i, sub->obits);
1037
            if(bits[i] < bits[opt_order]) {
1038
                opt_order = i;
1039
            }
1040
        }
1041
        sub->order = opt_order;
1042
        sub->type = FLAC_SUBFRAME_FIXED;
1043
        sub->type_code = sub->type | sub->order;
1044
        if(sub->order != max_order) {
1045
            encode_residual_fixed(res, smp, n, sub->order);
1046
            return calc_rice_params_fixed(&sub->rc, min_porder, max_porder, res, n,
1047
                                          sub->order, sub->obits);
1048
        }
1049
        return bits[sub->order];
1050
    }
1051

    
1052
    /* LPC */
1053
    opt_order = lpc_calc_coefs(ctx, smp, n, max_order, precision, coefs, shift, ctx->options.use_lpc, omethod);
1054

    
1055
    if(omethod == ORDER_METHOD_2LEVEL ||
1056
       omethod == ORDER_METHOD_4LEVEL ||
1057
       omethod == ORDER_METHOD_8LEVEL) {
1058
        int levels = 1 << omethod;
1059
        uint32_t bits[levels];
1060
        int order;
1061
        int opt_index = levels-1;
1062
        opt_order = max_order-1;
1063
        bits[opt_index] = UINT32_MAX;
1064
        for(i=levels-1; i>=0; i--) {
1065
            order = min_order + (((max_order-min_order+1) * (i+1)) / levels)-1;
1066
            if(order < 0) order = 0;
1067
            encode_residual_lpc(res, smp, n, order+1, coefs[order], shift[order]);
1068
            bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
1069
                                           res, n, order+1, sub->obits, precision);
1070
            if(bits[i] < bits[opt_index]) {
1071
                opt_index = i;
1072
                opt_order = order;
1073
            }
1074
        }
1075
        opt_order++;
1076
    } else if(omethod == ORDER_METHOD_SEARCH) {
1077
        // brute-force optimal order search
1078
        uint32_t bits[MAX_LPC_ORDER];
1079
        opt_order = 0;
1080
        bits[0] = UINT32_MAX;
1081
        for(i=min_order-1; i<max_order; i++) {
1082
            encode_residual_lpc(res, smp, n, i+1, coefs[i], shift[i]);
1083
            bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
1084
                                           res, n, i+1, sub->obits, precision);
1085
            if(bits[i] < bits[opt_order]) {
1086
                opt_order = i;
1087
            }
1088
        }
1089
        opt_order++;
1090
    } else if(omethod == ORDER_METHOD_LOG) {
1091
        uint32_t bits[MAX_LPC_ORDER];
1092
        int step;
1093

    
1094
        opt_order= min_order - 1 + (max_order-min_order)/3;
1095
        memset(bits, -1, sizeof(bits));
1096

    
1097
        for(step=16 ;step; step>>=1){
1098
            int last= opt_order;
1099
            for(i=last-step; i<=last+step; i+= step){
1100
                if(i<min_order-1 || i>=max_order || bits[i] < UINT32_MAX)
1101
                    continue;
1102
                encode_residual_lpc(res, smp, n, i+1, coefs[i], shift[i]);
1103
                bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
1104
                                            res, n, i+1, sub->obits, precision);
1105
                if(bits[i] < bits[opt_order])
1106
                    opt_order= i;
1107
            }
1108
        }
1109
        opt_order++;
1110
    }
1111

    
1112
    sub->order = opt_order;
1113
    sub->type = FLAC_SUBFRAME_LPC;
1114
    sub->type_code = sub->type | (sub->order-1);
1115
    sub->shift = shift[sub->order-1];
1116
    for(i=0; i<sub->order; i++) {
1117
        sub->coefs[i] = coefs[sub->order-1][i];
1118
    }
1119
    encode_residual_lpc(res, smp, n, sub->order, sub->coefs, sub->shift);
1120
    return calc_rice_params_lpc(&sub->rc, min_porder, max_porder, res, n, sub->order,
1121
                                sub->obits, precision);
1122
}
1123

    
1124
static int encode_residual_v(FlacEncodeContext *ctx, int ch)
1125
{
1126
    int i, n;
1127
    FlacFrame *frame;
1128
    FlacSubframe *sub;
1129
    int32_t *res, *smp;
1130

    
1131
    frame = &ctx->frame;
1132
    sub = &frame->subframes[ch];
1133
    res = sub->residual;
1134
    smp = sub->samples;
1135
    n = frame->blocksize;
1136

    
1137
    /* CONSTANT */
1138
    for(i=1; i<n; i++) {
1139
        if(smp[i] != smp[0]) break;
1140
    }
1141
    if(i == n) {
1142
        sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
1143
        res[0] = smp[0];
1144
        return sub->obits;
1145
    }
1146

    
1147
    /* VERBATIM */
1148
    sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
1149
    encode_residual_verbatim(res, smp, n);
1150
    return sub->obits * n;
1151
}
1152

    
1153
static int estimate_stereo_mode(int32_t *left_ch, int32_t *right_ch, int n)
1154
{
1155
    int i, best;
1156
    int32_t lt, rt;
1157
    uint64_t sum[4];
1158
    uint64_t score[4];
1159
    int k;
1160

    
1161
    /* calculate sum of 2nd order residual for each channel */
1162
    sum[0] = sum[1] = sum[2] = sum[3] = 0;
1163
    for(i=2; i<n; i++) {
1164
        lt = left_ch[i] - 2*left_ch[i-1] + left_ch[i-2];
1165
        rt = right_ch[i] - 2*right_ch[i-1] + right_ch[i-2];
1166
        sum[2] += FFABS((lt + rt) >> 1);
1167
        sum[3] += FFABS(lt - rt);
1168
        sum[0] += FFABS(lt);
1169
        sum[1] += FFABS(rt);
1170
    }
1171
    /* estimate bit counts */
1172
    for(i=0; i<4; i++) {
1173
        k = find_optimal_param(2*sum[i], n);
1174
        sum[i] = rice_encode_count(2*sum[i], n, k);
1175
    }
1176

    
1177
    /* calculate score for each mode */
1178
    score[0] = sum[0] + sum[1];
1179
    score[1] = sum[0] + sum[3];
1180
    score[2] = sum[1] + sum[3];
1181
    score[3] = sum[2] + sum[3];
1182

    
1183
    /* return mode with lowest score */
1184
    best = 0;
1185
    for(i=1; i<4; i++) {
1186
        if(score[i] < score[best]) {
1187
            best = i;
1188
        }
1189
    }
1190
    if(best == 0) {
1191
        return FLAC_CHMODE_LEFT_RIGHT;
1192
    } else if(best == 1) {
1193
        return FLAC_CHMODE_LEFT_SIDE;
1194
    } else if(best == 2) {
1195
        return FLAC_CHMODE_RIGHT_SIDE;
1196
    } else {
1197
        return FLAC_CHMODE_MID_SIDE;
1198
    }
1199
}
1200

    
1201
/**
1202
 * Perform stereo channel decorrelation
1203
 */
1204
static void channel_decorrelation(FlacEncodeContext *ctx)
1205
{
1206
    FlacFrame *frame;
1207
    int32_t *left, *right;
1208
    int i, n;
1209

    
1210
    frame = &ctx->frame;
1211
    n = frame->blocksize;
1212
    left  = frame->subframes[0].samples;
1213
    right = frame->subframes[1].samples;
1214

    
1215
    if(ctx->channels != 2) {
1216
        frame->ch_mode = FLAC_CHMODE_NOT_STEREO;
1217
        return;
1218
    }
1219

    
1220
    frame->ch_mode = estimate_stereo_mode(left, right, n);
1221

    
1222
    /* perform decorrelation and adjust bits-per-sample */
1223
    if(frame->ch_mode == FLAC_CHMODE_LEFT_RIGHT) {
1224
        return;
1225
    }
1226
    if(frame->ch_mode == FLAC_CHMODE_MID_SIDE) {
1227
        int32_t tmp;
1228
        for(i=0; i<n; i++) {
1229
            tmp = left[i];
1230
            left[i] = (tmp + right[i]) >> 1;
1231
            right[i] = tmp - right[i];
1232
        }
1233
        frame->subframes[1].obits++;
1234
    } else if(frame->ch_mode == FLAC_CHMODE_LEFT_SIDE) {
1235
        for(i=0; i<n; i++) {
1236
            right[i] = left[i] - right[i];
1237
        }
1238
        frame->subframes[1].obits++;
1239
    } else {
1240
        for(i=0; i<n; i++) {
1241
            left[i] -= right[i];
1242
        }
1243
        frame->subframes[0].obits++;
1244
    }
1245
}
1246

    
1247
static void put_sbits(PutBitContext *pb, int bits, int32_t val)
1248
{
1249
    assert(bits >= 0 && bits <= 31);
1250

    
1251
    put_bits(pb, bits, val & ((1<<bits)-1));
1252
}
1253

    
1254
static void write_utf8(PutBitContext *pb, uint32_t val)
1255
{
1256
    uint8_t tmp;
1257
    PUT_UTF8(val, tmp, put_bits(pb, 8, tmp);)
1258
}
1259

    
1260
static void output_frame_header(FlacEncodeContext *s)
1261
{
1262
    FlacFrame *frame;
1263
    int crc;
1264

    
1265
    frame = &s->frame;
1266

    
1267
    put_bits(&s->pb, 16, 0xFFF8);
1268
    put_bits(&s->pb, 4, frame->bs_code[0]);
1269
    put_bits(&s->pb, 4, s->sr_code[0]);
1270
    if(frame->ch_mode == FLAC_CHMODE_NOT_STEREO) {
1271
        put_bits(&s->pb, 4, s->ch_code);
1272
    } else {
1273
        put_bits(&s->pb, 4, frame->ch_mode);
1274
    }
1275
    put_bits(&s->pb, 3, 4); /* bits-per-sample code */
1276
    put_bits(&s->pb, 1, 0);
1277
    write_utf8(&s->pb, s->frame_count);
1278
    if(frame->bs_code[0] == 6) {
1279
        put_bits(&s->pb, 8, frame->bs_code[1]);
1280
    } else if(frame->bs_code[0] == 7) {
1281
        put_bits(&s->pb, 16, frame->bs_code[1]);
1282
    }
1283
    if(s->sr_code[0] == 12) {
1284
        put_bits(&s->pb, 8, s->sr_code[1]);
1285
    } else if(s->sr_code[0] > 12) {
1286
        put_bits(&s->pb, 16, s->sr_code[1]);
1287
    }
1288
    flush_put_bits(&s->pb);
1289
    crc = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
1290
                 s->pb.buf, put_bits_count(&s->pb)>>3);
1291
    put_bits(&s->pb, 8, crc);
1292
}
1293

    
1294
static void output_subframe_constant(FlacEncodeContext *s, int ch)
1295
{
1296
    FlacSubframe *sub;
1297
    int32_t res;
1298

    
1299
    sub = &s->frame.subframes[ch];
1300
    res = sub->residual[0];
1301
    put_sbits(&s->pb, sub->obits, res);
1302
}
1303

    
1304
static void output_subframe_verbatim(FlacEncodeContext *s, int ch)
1305
{
1306
    int i;
1307
    FlacFrame *frame;
1308
    FlacSubframe *sub;
1309
    int32_t res;
1310

    
1311
    frame = &s->frame;
1312
    sub = &frame->subframes[ch];
1313

    
1314
    for(i=0; i<frame->blocksize; i++) {
1315
        res = sub->residual[i];
1316
        put_sbits(&s->pb, sub->obits, res);
1317
    }
1318
}
1319

    
1320
static void output_residual(FlacEncodeContext *ctx, int ch)
1321
{
1322
    int i, j, p, n, parts;
1323
    int k, porder, psize, res_cnt;
1324
    FlacFrame *frame;
1325
    FlacSubframe *sub;
1326
    int32_t *res;
1327

    
1328
    frame = &ctx->frame;
1329
    sub = &frame->subframes[ch];
1330
    res = sub->residual;
1331
    n = frame->blocksize;
1332

    
1333
    /* rice-encoded block */
1334
    put_bits(&ctx->pb, 2, 0);
1335

    
1336
    /* partition order */
1337
    porder = sub->rc.porder;
1338
    psize = n >> porder;
1339
    parts = (1 << porder);
1340
    put_bits(&ctx->pb, 4, porder);
1341
    res_cnt = psize - sub->order;
1342

    
1343
    /* residual */
1344
    j = sub->order;
1345
    for(p=0; p<parts; p++) {
1346
        k = sub->rc.params[p];
1347
        put_bits(&ctx->pb, 4, k);
1348
        if(p == 1) res_cnt = psize;
1349
        for(i=0; i<res_cnt && j<n; i++, j++) {
1350
            set_sr_golomb_flac(&ctx->pb, res[j], k, INT32_MAX, 0);
1351
        }
1352
    }
1353
}
1354

    
1355
static void output_subframe_fixed(FlacEncodeContext *ctx, int ch)
1356
{
1357
    int i;
1358
    FlacFrame *frame;
1359
    FlacSubframe *sub;
1360

    
1361
    frame = &ctx->frame;
1362
    sub = &frame->subframes[ch];
1363

    
1364
    /* warm-up samples */
1365
    for(i=0; i<sub->order; i++) {
1366
        put_sbits(&ctx->pb, sub->obits, sub->residual[i]);
1367
    }
1368

    
1369
    /* residual */
1370
    output_residual(ctx, ch);
1371
}
1372

    
1373
static void output_subframe_lpc(FlacEncodeContext *ctx, int ch)
1374
{
1375
    int i, cbits;
1376
    FlacFrame *frame;
1377
    FlacSubframe *sub;
1378

    
1379
    frame = &ctx->frame;
1380
    sub = &frame->subframes[ch];
1381

    
1382
    /* warm-up samples */
1383
    for(i=0; i<sub->order; i++) {
1384
        put_sbits(&ctx->pb, sub->obits, sub->residual[i]);
1385
    }
1386

    
1387
    /* LPC coefficients */
1388
    cbits = ctx->options.lpc_coeff_precision;
1389
    put_bits(&ctx->pb, 4, cbits-1);
1390
    put_sbits(&ctx->pb, 5, sub->shift);
1391
    for(i=0; i<sub->order; i++) {
1392
        put_sbits(&ctx->pb, cbits, sub->coefs[i]);
1393
    }
1394

    
1395
    /* residual */
1396
    output_residual(ctx, ch);
1397
}
1398

    
1399
static void output_subframes(FlacEncodeContext *s)
1400
{
1401
    FlacFrame *frame;
1402
    FlacSubframe *sub;
1403
    int ch;
1404

    
1405
    frame = &s->frame;
1406

    
1407
    for(ch=0; ch<s->channels; ch++) {
1408
        sub = &frame->subframes[ch];
1409

    
1410
        /* subframe header */
1411
        put_bits(&s->pb, 1, 0);
1412
        put_bits(&s->pb, 6, sub->type_code);
1413
        put_bits(&s->pb, 1, 0); /* no wasted bits */
1414

    
1415
        /* subframe */
1416
        if(sub->type == FLAC_SUBFRAME_CONSTANT) {
1417
            output_subframe_constant(s, ch);
1418
        } else if(sub->type == FLAC_SUBFRAME_VERBATIM) {
1419
            output_subframe_verbatim(s, ch);
1420
        } else if(sub->type == FLAC_SUBFRAME_FIXED) {
1421
            output_subframe_fixed(s, ch);
1422
        } else if(sub->type == FLAC_SUBFRAME_LPC) {
1423
            output_subframe_lpc(s, ch);
1424
        }
1425
    }
1426
}
1427

    
1428
static void output_frame_footer(FlacEncodeContext *s)
1429
{
1430
    int crc;
1431
    flush_put_bits(&s->pb);
1432
    crc = bswap_16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
1433
                          s->pb.buf, put_bits_count(&s->pb)>>3));
1434
    put_bits(&s->pb, 16, crc);
1435
    flush_put_bits(&s->pb);
1436
}
1437

    
1438
static int flac_encode_frame(AVCodecContext *avctx, uint8_t *frame,
1439
                             int buf_size, void *data)
1440
{
1441
    int ch;
1442
    FlacEncodeContext *s;
1443
    int16_t *samples = data;
1444
    int out_bytes;
1445

    
1446
    s = avctx->priv_data;
1447

    
1448
    s->blocksize = avctx->frame_size;
1449
    init_frame(s);
1450

    
1451
    copy_samples(s, samples);
1452

    
1453
    channel_decorrelation(s);
1454

    
1455
    for(ch=0; ch<s->channels; ch++) {
1456
        encode_residual(s, ch);
1457
    }
1458
    init_put_bits(&s->pb, frame, buf_size);
1459
    output_frame_header(s);
1460
    output_subframes(s);
1461
    output_frame_footer(s);
1462
    out_bytes = put_bits_count(&s->pb) >> 3;
1463

    
1464
    if(out_bytes > s->max_framesize || out_bytes >= buf_size) {
1465
        /* frame too large. use verbatim mode */
1466
        for(ch=0; ch<s->channels; ch++) {
1467
            encode_residual_v(s, ch);
1468
        }
1469
        init_put_bits(&s->pb, frame, buf_size);
1470
        output_frame_header(s);
1471
        output_subframes(s);
1472
        output_frame_footer(s);
1473
        out_bytes = put_bits_count(&s->pb) >> 3;
1474

    
1475
        if(out_bytes > s->max_framesize || out_bytes >= buf_size) {
1476
            /* still too large. must be an error. */
1477
            av_log(avctx, AV_LOG_ERROR, "error encoding frame\n");
1478
            return -1;
1479
        }
1480
    }
1481

    
1482
    s->frame_count++;
1483
    return out_bytes;
1484
}
1485

    
1486
static int flac_encode_close(AVCodecContext *avctx)
1487
{
1488
    av_freep(&avctx->extradata);
1489
    avctx->extradata_size = 0;
1490
    av_freep(&avctx->coded_frame);
1491
    return 0;
1492
}
1493

    
1494
AVCodec flac_encoder = {
1495
    "flac",
1496
    CODEC_TYPE_AUDIO,
1497
    CODEC_ID_FLAC,
1498
    sizeof(FlacEncodeContext),
1499
    flac_encode_init,
1500
    flac_encode_frame,
1501
    flac_encode_close,
1502
    NULL,
1503
    .capabilities = CODEC_CAP_SMALL_LAST_FRAME,
1504
};