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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
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 * 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
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
21

    
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#include "libavutil/crc.h"
23
#include "libavutil/lls.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"
29

    
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#define FLAC_MAX_CH  8
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#define FLAC_MIN_BLOCKSIZE  16
32
#define FLAC_MAX_BLOCKSIZE  65535
33

    
34
#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
38

    
39
#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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#define FLAC_STREAMINFO_SIZE  34
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47
#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
53

    
54
typedef struct CompressionOptions {
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    int compression_level;
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    int block_time_ms;
57
    int use_lpc;
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    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;
64
} CompressionOptions;
65

    
66
typedef struct RiceContext {
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    int porder;
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    int params[MAX_PARTITIONS];
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} RiceContext;
70

    
71
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];
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} FlacSubframe;
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83
typedef struct FlacFrame {
84
    FlacSubframe subframes[FLAC_MAX_CH];
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    int blocksize;
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    int bs_code[2];
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    uint8_t crc8;
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    int ch_mode;
89
} FlacFrame;
90

    
91
typedef struct FlacEncodeContext {
92
    PutBitContext pb;
93
    int channels;
94
    int ch_code;
95
    int samplerate;
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    int sr_code[2];
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    int max_framesize;
98
    uint32_t frame_count;
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    FlacFrame frame;
100
    CompressionOptions options;
101
    AVCodecContext *avctx;
102
    DSPContext dsp;
103
} FlacEncodeContext;
104

    
105
static const int flac_samplerates[16] = {
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    0, 0, 0, 0,
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    8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
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    0, 0, 0, 0
109
};
110

    
111
static const int flac_blocksizes[16] = {
112
    0,
113
    192,
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    576, 1152, 2304, 4608,
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    0, 0,
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    256, 512, 1024, 2048, 4096, 8192, 16384, 32768
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};
118

    
119
/**
120
 * Writes streaminfo metadata block to byte array
121
 */
122
static void write_streaminfo(FlacEncodeContext *s, uint8_t *header)
123
{
124
    PutBitContext pb;
125

    
126
    memset(header, 0, FLAC_STREAMINFO_SIZE);
127
    init_put_bits(&pb, header, FLAC_STREAMINFO_SIZE);
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    /* streaminfo metadata block */
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    put_bits(&pb, 16, s->avctx->frame_size);
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    put_bits(&pb, 16, s->avctx->frame_size);
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    put_bits(&pb, 24, 0);
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    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);
138
    /* total samples = 0 */
139
    /* MD5 signature = 0 */
140
}
141

    
142
/**
143
 * Sets blocksize based on samplerate
144
 * Chooses the closest predefined blocksize >= BLOCK_TIME_MS milliseconds
145
 */
146
static int select_blocksize(int samplerate, int block_time_ms)
147
{
148
    int i;
149
    int target;
150
    int blocksize;
151

    
152
    assert(samplerate > 0);
153
    blocksize = flac_blocksizes[1];
154
    target = (samplerate * block_time_ms) / 1000;
155
    for(i=0; i<16; i++) {
156
        if(target >= flac_blocksizes[i] && flac_blocksizes[i] > blocksize) {
157
            blocksize = flac_blocksizes[i];
158
        }
159
    }
160
    return blocksize;
161
}
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163
static av_cold int flac_encode_init(AVCodecContext *avctx)
164
{
165
    int freq = avctx->sample_rate;
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    int channels = avctx->channels;
167
    FlacEncodeContext *s = avctx->priv_data;
168
    int i, level;
169
    uint8_t *streaminfo;
170

    
171
    s->avctx = avctx;
172

    
173
    dsputil_init(&s->dsp, avctx);
174

    
175
    if(avctx->sample_fmt != SAMPLE_FMT_S16) {
176
        return -1;
177
    }
178

    
179
    if(channels < 1 || channels > FLAC_MAX_CH) {
180
        return -1;
181
    }
182
    s->channels = channels;
183
    s->ch_code = s->channels-1;
184

    
185
    /* find samplerate in table */
186
    if(freq < 1)
187
        return -1;
188
    for(i=4; i<12; i++) {
189
        if(freq == flac_samplerates[i]) {
190
            s->samplerate = flac_samplerates[i];
191
            s->sr_code[0] = i;
192
            s->sr_code[1] = 0;
193
            break;
194
        }
195
    }
196
    /* if not in table, samplerate is non-standard */
197
    if(i == 12) {
198
        if(freq % 1000 == 0 && freq < 255000) {
199
            s->sr_code[0] = 12;
200
            s->sr_code[1] = freq / 1000;
201
        } else if(freq % 10 == 0 && freq < 655350) {
202
            s->sr_code[0] = 14;
203
            s->sr_code[1] = freq / 10;
204
        } else if(freq < 65535) {
205
            s->sr_code[0] = 13;
206
            s->sr_code[1] = freq;
207
        } else {
208
            return -1;
209
        }
210
        s->samplerate = freq;
211
    }
212

    
213
    /* set compression option defaults based on avctx->compression_level */
214
    if(avctx->compression_level < 0) {
215
        s->options.compression_level = 5;
216
    } else {
217
        s->options.compression_level = avctx->compression_level;
218
    }
219
    av_log(avctx, AV_LOG_DEBUG, " compression: %d\n", s->options.compression_level);
220

    
221
    level= s->options.compression_level;
222
    if(level > 12) {
223
        av_log(avctx, AV_LOG_ERROR, "invalid compression level: %d\n",
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               s->options.compression_level);
225
        return -1;
226
    }
227

    
228
    s->options.block_time_ms       = ((int[]){ 27, 27, 27,105,105,105,105,105,105,105,105,105,105})[level];
229
    s->options.use_lpc             = ((int[]){  0,  0,  0,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1})[level];
230
    s->options.min_prediction_order= ((int[]){  2,  0,  0,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1})[level];
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    s->options.max_prediction_order= ((int[]){  3,  4,  4,  6,  8,  8,  8,  8, 12, 12, 12, 32, 32})[level];
232
    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,
236
                                                   ORDER_METHOD_SEARCH})[level];
237
    s->options.min_partition_order = ((int[]){  2,  2,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0})[level];
238
    s->options.max_partition_order = ((int[]){  2,  2,  3,  3,  3,  8,  8,  8,  8,  8,  8,  8,  8})[level];
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240
    /* set compression option overrides from AVCodecContext */
241
    if(avctx->use_lpc >= 0) {
242
        s->options.use_lpc = av_clip(avctx->use_lpc, 0, 11);
243
    }
244
    if(s->options.use_lpc == 1)
245
        av_log(avctx, AV_LOG_DEBUG, " use lpc: Levinson-Durbin recursion with Welch window\n");
246
    else if(s->options.use_lpc > 1)
247
        av_log(avctx, AV_LOG_DEBUG, " use lpc: Cholesky factorization\n");
248

    
249
    if(avctx->min_prediction_order >= 0) {
250
        if(s->options.use_lpc) {
251
            if(avctx->min_prediction_order < MIN_LPC_ORDER ||
252
                    avctx->min_prediction_order > MAX_LPC_ORDER) {
253
                av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
254
                       avctx->min_prediction_order);
255
                return -1;
256
            }
257
        } else {
258
            if(avctx->min_prediction_order > MAX_FIXED_ORDER) {
259
                av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
260
                       avctx->min_prediction_order);
261
                return -1;
262
            }
263
        }
264
        s->options.min_prediction_order = avctx->min_prediction_order;
265
    }
266
    if(avctx->max_prediction_order >= 0) {
267
        if(s->options.use_lpc) {
268
            if(avctx->max_prediction_order < MIN_LPC_ORDER ||
269
                    avctx->max_prediction_order > MAX_LPC_ORDER) {
270
                av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
271
                       avctx->max_prediction_order);
272
                return -1;
273
            }
274
        } else {
275
            if(avctx->max_prediction_order > MAX_FIXED_ORDER) {
276
                av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
277
                       avctx->max_prediction_order);
278
                return -1;
279
            }
280
        }
281
        s->options.max_prediction_order = avctx->max_prediction_order;
282
    }
283
    if(s->options.max_prediction_order < s->options.min_prediction_order) {
284
        av_log(avctx, AV_LOG_ERROR, "invalid prediction orders: min=%d max=%d\n",
285
               s->options.min_prediction_order, s->options.max_prediction_order);
286
        return -1;
287
    }
288
    av_log(avctx, AV_LOG_DEBUG, " prediction order: %d, %d\n",
289
           s->options.min_prediction_order, s->options.max_prediction_order);
290

    
291
    if(avctx->prediction_order_method >= 0) {
292
        if(avctx->prediction_order_method > ORDER_METHOD_LOG) {
293
            av_log(avctx, AV_LOG_ERROR, "invalid prediction order method: %d\n",
294
                   avctx->prediction_order_method);
295
            return -1;
296
        }
297
        s->options.prediction_order_method = avctx->prediction_order_method;
298
    }
299
    switch(s->options.prediction_order_method) {
300
        case ORDER_METHOD_EST:    av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
301
                                         "estimate"); break;
302
        case ORDER_METHOD_2LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
303
                                         "2-level"); break;
304
        case ORDER_METHOD_4LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
305
                                         "4-level"); break;
306
        case ORDER_METHOD_8LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
307
                                         "8-level"); break;
308
        case ORDER_METHOD_SEARCH: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
309
                                         "full search"); break;
310
        case ORDER_METHOD_LOG:    av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
311
                                         "log search"); break;
312
    }
313

    
314
    if(avctx->min_partition_order >= 0) {
315
        if(avctx->min_partition_order > MAX_PARTITION_ORDER) {
316
            av_log(avctx, AV_LOG_ERROR, "invalid min partition order: %d\n",
317
                   avctx->min_partition_order);
318
            return -1;
319
        }
320
        s->options.min_partition_order = avctx->min_partition_order;
321
    }
322
    if(avctx->max_partition_order >= 0) {
323
        if(avctx->max_partition_order > MAX_PARTITION_ORDER) {
324
            av_log(avctx, AV_LOG_ERROR, "invalid max partition order: %d\n",
325
                   avctx->max_partition_order);
326
            return -1;
327
        }
328
        s->options.max_partition_order = avctx->max_partition_order;
329
    }
330
    if(s->options.max_partition_order < s->options.min_partition_order) {
331
        av_log(avctx, AV_LOG_ERROR, "invalid partition orders: min=%d max=%d\n",
332
               s->options.min_partition_order, s->options.max_partition_order);
333
        return -1;
334
    }
335
    av_log(avctx, AV_LOG_DEBUG, " partition order: %d, %d\n",
336
           s->options.min_partition_order, s->options.max_partition_order);
337

    
338
    if(avctx->frame_size > 0) {
339
        if(avctx->frame_size < FLAC_MIN_BLOCKSIZE ||
340
                avctx->frame_size > FLAC_MAX_BLOCKSIZE) {
341
            av_log(avctx, AV_LOG_ERROR, "invalid block size: %d\n",
342
                   avctx->frame_size);
343
            return -1;
344
        }
345
    } else {
346
        s->avctx->frame_size = select_blocksize(s->samplerate, s->options.block_time_ms);
347
    }
348
    av_log(avctx, AV_LOG_DEBUG, " block size: %d\n", s->avctx->frame_size);
349

    
350
    /* set LPC precision */
351
    if(avctx->lpc_coeff_precision > 0) {
352
        if(avctx->lpc_coeff_precision > MAX_LPC_PRECISION) {
353
            av_log(avctx, AV_LOG_ERROR, "invalid lpc coeff precision: %d\n",
354
                   avctx->lpc_coeff_precision);
355
            return -1;
356
        }
357
        s->options.lpc_coeff_precision = avctx->lpc_coeff_precision;
358
    } else {
359
        /* default LPC precision */
360
        s->options.lpc_coeff_precision = 15;
361
    }
362
    av_log(avctx, AV_LOG_DEBUG, " lpc precision: %d\n",
363
           s->options.lpc_coeff_precision);
364

    
365
    /* set maximum encoded frame size in verbatim mode */
366
    if(s->channels == 2) {
367
        s->max_framesize = 14 + ((s->avctx->frame_size * 33 + 7) >> 3);
368
    } else {
369
        s->max_framesize = 14 + (s->avctx->frame_size * s->channels * 2);
370
    }
371

    
372
    streaminfo = av_malloc(FLAC_STREAMINFO_SIZE);
373
    write_streaminfo(s, streaminfo);
374
    avctx->extradata = streaminfo;
375
    avctx->extradata_size = FLAC_STREAMINFO_SIZE;
376

    
377
    s->frame_count = 0;
378

    
379
    avctx->coded_frame = avcodec_alloc_frame();
380
    avctx->coded_frame->key_frame = 1;
381

    
382
    return 0;
383
}
384

    
385
static void init_frame(FlacEncodeContext *s)
386
{
387
    int i, ch;
388
    FlacFrame *frame;
389

    
390
    frame = &s->frame;
391

    
392
    for(i=0; i<16; i++) {
393
        if(s->avctx->frame_size == flac_blocksizes[i]) {
394
            frame->blocksize = flac_blocksizes[i];
395
            frame->bs_code[0] = i;
396
            frame->bs_code[1] = 0;
397
            break;
398
        }
399
    }
400
    if(i == 16) {
401
        frame->blocksize = s->avctx->frame_size;
402
        if(frame->blocksize <= 256) {
403
            frame->bs_code[0] = 6;
404
            frame->bs_code[1] = frame->blocksize-1;
405
        } else {
406
            frame->bs_code[0] = 7;
407
            frame->bs_code[1] = frame->blocksize-1;
408
        }
409
    }
410

    
411
    for(ch=0; ch<s->channels; ch++) {
412
        frame->subframes[ch].obits = 16;
413
    }
414
}
415

    
416
/**
417
 * Copy channel-interleaved input samples into separate subframes
418
 */
419
static void copy_samples(FlacEncodeContext *s, int16_t *samples)
420
{
421
    int i, j, ch;
422
    FlacFrame *frame;
423

    
424
    frame = &s->frame;
425
    for(i=0,j=0; i<frame->blocksize; i++) {
426
        for(ch=0; ch<s->channels; ch++,j++) {
427
            frame->subframes[ch].samples[i] = samples[j];
428
        }
429
    }
430
}
431

    
432

    
433
#define rice_encode_count(sum, n, k) (((n)*((k)+1))+((sum-(n>>1))>>(k)))
434

    
435
/**
436
 * Solve for d/dk(rice_encode_count) = n-((sum-(n>>1))>>(k+1)) = 0
437
 */
438
static int find_optimal_param(uint32_t sum, int n)
439
{
440
    int k;
441
    uint32_t sum2;
442

    
443
    if(sum <= n>>1)
444
        return 0;
445
    sum2 = sum-(n>>1);
446
    k = av_log2(n<256 ? FASTDIV(sum2,n) : sum2/n);
447
    return FFMIN(k, MAX_RICE_PARAM);
448
}
449

    
450
static uint32_t calc_optimal_rice_params(RiceContext *rc, int porder,
451
                                         uint32_t *sums, int n, int pred_order)
452
{
453
    int i;
454
    int k, cnt, part;
455
    uint32_t all_bits;
456

    
457
    part = (1 << porder);
458
    all_bits = 4 * part;
459

    
460
    cnt = (n >> porder) - pred_order;
461
    for(i=0; i<part; i++) {
462
        k = find_optimal_param(sums[i], cnt);
463
        rc->params[i] = k;
464
        all_bits += rice_encode_count(sums[i], cnt, k);
465
        cnt = n >> porder;
466
    }
467

    
468
    rc->porder = porder;
469

    
470
    return all_bits;
471
}
472

    
473
static void calc_sums(int pmin, int pmax, uint32_t *data, int n, int pred_order,
474
                      uint32_t sums[][MAX_PARTITIONS])
475
{
476
    int i, j;
477
    int parts;
478
    uint32_t *res, *res_end;
479

    
480
    /* sums for highest level */
481
    parts = (1 << pmax);
482
    res = &data[pred_order];
483
    res_end = &data[n >> pmax];
484
    for(i=0; i<parts; i++) {
485
        uint32_t sum = 0;
486
        while(res < res_end){
487
            sum += *(res++);
488
        }
489
        sums[pmax][i] = sum;
490
        res_end+= n >> pmax;
491
    }
492
    /* sums for lower levels */
493
    for(i=pmax-1; i>=pmin; i--) {
494
        parts = (1 << i);
495
        for(j=0; j<parts; j++) {
496
            sums[i][j] = sums[i+1][2*j] + sums[i+1][2*j+1];
497
        }
498
    }
499
}
500

    
501
static uint32_t calc_rice_params(RiceContext *rc, int pmin, int pmax,
502
                                 int32_t *data, int n, int pred_order)
503
{
504
    int i;
505
    uint32_t bits[MAX_PARTITION_ORDER+1];
506
    int opt_porder;
507
    RiceContext tmp_rc;
508
    uint32_t *udata;
509
    uint32_t sums[MAX_PARTITION_ORDER+1][MAX_PARTITIONS];
510

    
511
    assert(pmin >= 0 && pmin <= MAX_PARTITION_ORDER);
512
    assert(pmax >= 0 && pmax <= MAX_PARTITION_ORDER);
513
    assert(pmin <= pmax);
514

    
515
    udata = av_malloc(n * sizeof(uint32_t));
516
    for(i=0; i<n; i++) {
517
        udata[i] = (2*data[i]) ^ (data[i]>>31);
518
    }
519

    
520
    calc_sums(pmin, pmax, udata, n, pred_order, sums);
521

    
522
    opt_porder = pmin;
523
    bits[pmin] = UINT32_MAX;
524
    for(i=pmin; i<=pmax; i++) {
525
        bits[i] = calc_optimal_rice_params(&tmp_rc, i, sums[i], n, pred_order);
526
        if(bits[i] <= bits[opt_porder]) {
527
            opt_porder = i;
528
            *rc= tmp_rc;
529
        }
530
    }
531

    
532
    av_freep(&udata);
533
    return bits[opt_porder];
534
}
535

    
536
static int get_max_p_order(int max_porder, int n, int order)
537
{
538
    int porder = FFMIN(max_porder, av_log2(n^(n-1)));
539
    if(order > 0)
540
        porder = FFMIN(porder, av_log2(n/order));
541
    return porder;
542
}
543

    
544
static uint32_t calc_rice_params_fixed(RiceContext *rc, int pmin, int pmax,
545
                                       int32_t *data, int n, int pred_order,
546
                                       int bps)
547
{
548
    uint32_t bits;
549
    pmin = get_max_p_order(pmin, n, pred_order);
550
    pmax = get_max_p_order(pmax, n, pred_order);
551
    bits = pred_order*bps + 6;
552
    bits += calc_rice_params(rc, pmin, pmax, data, n, pred_order);
553
    return bits;
554
}
555

    
556
static uint32_t calc_rice_params_lpc(RiceContext *rc, int pmin, int pmax,
557
                                     int32_t *data, int n, int pred_order,
558
                                     int bps, int precision)
559
{
560
    uint32_t bits;
561
    pmin = get_max_p_order(pmin, n, pred_order);
562
    pmax = get_max_p_order(pmax, n, pred_order);
563
    bits = pred_order*bps + 4 + 5 + pred_order*precision + 6;
564
    bits += calc_rice_params(rc, pmin, pmax, data, n, pred_order);
565
    return bits;
566
}
567

    
568
/**
569
 * Apply Welch window function to audio block
570
 */
571
static void apply_welch_window(const int32_t *data, int len, double *w_data)
572
{
573
    int i, n2;
574
    double w;
575
    double c;
576

    
577
    assert(!(len&1)); //the optimization in r11881 does not support odd len
578
                      //if someone wants odd len extend the change in r11881
579

    
580
    n2 = (len >> 1);
581
    c = 2.0 / (len - 1.0);
582

    
583
    w_data+=n2;
584
      data+=n2;
585
    for(i=0; i<n2; i++) {
586
        w = c - n2 + i;
587
        w = 1.0 - (w * w);
588
        w_data[-i-1] = data[-i-1] * w;
589
        w_data[+i  ] = data[+i  ] * w;
590
    }
591
}
592

    
593
/**
594
 * Calculates autocorrelation data from audio samples
595
 * A Welch window function is applied before calculation.
596
 */
597
void ff_flac_compute_autocorr(const int32_t *data, int len, int lag,
598
                              double *autoc)
599
{
600
    int i, j;
601
    double tmp[len + lag + 1];
602
    double *data1= tmp + lag;
603

    
604
    apply_welch_window(data, len, data1);
605

    
606
    for(j=0; j<lag; j++)
607
        data1[j-lag]= 0.0;
608
    data1[len] = 0.0;
609

    
610
    for(j=0; j<lag; j+=2){
611
        double sum0 = 1.0, sum1 = 1.0;
612
        for(i=0; i<len; i++){
613
            sum0 += data1[i] * data1[i-j];
614
            sum1 += data1[i] * data1[i-j-1];
615
        }
616
        autoc[j  ] = sum0;
617
        autoc[j+1] = sum1;
618
    }
619

    
620
    if(j==lag){
621
        double sum = 1.0;
622
        for(i=0; i<len; i+=2){
623
            sum += data1[i  ] * data1[i-j  ]
624
                 + data1[i+1] * data1[i-j+1];
625
        }
626
        autoc[j] = sum;
627
    }
628
}
629

    
630

    
631
static void encode_residual_verbatim(int32_t *res, int32_t *smp, int n)
632
{
633
    assert(n > 0);
634
    memcpy(res, smp, n * sizeof(int32_t));
635
}
636

    
637
static void encode_residual_fixed(int32_t *res, const int32_t *smp, int n,
638
                                  int order)
639
{
640
    int i;
641

    
642
    for(i=0; i<order; i++) {
643
        res[i] = smp[i];
644
    }
645

    
646
    if(order==0){
647
        for(i=order; i<n; i++)
648
            res[i]= smp[i];
649
    }else if(order==1){
650
        for(i=order; i<n; i++)
651
            res[i]= smp[i] - smp[i-1];
652
    }else if(order==2){
653
        int a = smp[order-1] - smp[order-2];
654
        for(i=order; i<n; i+=2) {
655
            int b = smp[i] - smp[i-1];
656
            res[i]= b - a;
657
            a = smp[i+1] - smp[i];
658
            res[i+1]= a - b;
659
        }
660
    }else if(order==3){
661
        int a = smp[order-1] - smp[order-2];
662
        int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
663
        for(i=order; i<n; i+=2) {
664
            int b = smp[i] - smp[i-1];
665
            int d = b - a;
666
            res[i]= d - c;
667
            a = smp[i+1] - smp[i];
668
            c = a - b;
669
            res[i+1]= c - d;
670
        }
671
    }else{
672
        int a = smp[order-1] - smp[order-2];
673
        int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
674
        int e = smp[order-1] - 3*smp[order-2] + 3*smp[order-3] - smp[order-4];
675
        for(i=order; i<n; i+=2) {
676
            int b = smp[i] - smp[i-1];
677
            int d = b - a;
678
            int f = d - c;
679
            res[i]= f - e;
680
            a = smp[i+1] - smp[i];
681
            c = a - b;
682
            e = c - d;
683
            res[i+1]= e - f;
684
        }
685
    }
686
}
687

    
688
#define LPC1(x) {\
689
    int c = coefs[(x)-1];\
690
    p0 += c*s;\
691
    s = smp[i-(x)+1];\
692
    p1 += c*s;\
693
}
694

    
695
static av_always_inline void encode_residual_lpc_unrolled(
696
    int32_t *res, const int32_t *smp, int n,
697
    int order, const int32_t *coefs, int shift, int big)
698
{
699
    int i;
700
    for(i=order; i<n; i+=2) {
701
        int s = smp[i-order];
702
        int p0 = 0, p1 = 0;
703
        if(big) {
704
            switch(order) {
705
                case 32: LPC1(32)
706
                case 31: LPC1(31)
707
                case 30: LPC1(30)
708
                case 29: LPC1(29)
709
                case 28: LPC1(28)
710
                case 27: LPC1(27)
711
                case 26: LPC1(26)
712
                case 25: LPC1(25)
713
                case 24: LPC1(24)
714
                case 23: LPC1(23)
715
                case 22: LPC1(22)
716
                case 21: LPC1(21)
717
                case 20: LPC1(20)
718
                case 19: LPC1(19)
719
                case 18: LPC1(18)
720
                case 17: LPC1(17)
721
                case 16: LPC1(16)
722
                case 15: LPC1(15)
723
                case 14: LPC1(14)
724
                case 13: LPC1(13)
725
                case 12: LPC1(12)
726
                case 11: LPC1(11)
727
                case 10: LPC1(10)
728
                case  9: LPC1( 9)
729
                         LPC1( 8)
730
                         LPC1( 7)
731
                         LPC1( 6)
732
                         LPC1( 5)
733
                         LPC1( 4)
734
                         LPC1( 3)
735
                         LPC1( 2)
736
                         LPC1( 1)
737
            }
738
        } else {
739
            switch(order) {
740
                case  8: LPC1( 8)
741
                case  7: LPC1( 7)
742
                case  6: LPC1( 6)
743
                case  5: LPC1( 5)
744
                case  4: LPC1( 4)
745
                case  3: LPC1( 3)
746
                case  2: LPC1( 2)
747
                case  1: LPC1( 1)
748
            }
749
        }
750
        res[i  ] = smp[i  ] - (p0 >> shift);
751
        res[i+1] = smp[i+1] - (p1 >> shift);
752
    }
753
}
754

    
755
static void encode_residual_lpc(int32_t *res, const int32_t *smp, int n,
756
                                int order, const int32_t *coefs, int shift)
757
{
758
    int i;
759
    for(i=0; i<order; i++) {
760
        res[i] = smp[i];
761
    }
762
#ifdef CONFIG_SMALL
763
    for(i=order; i<n; i+=2) {
764
        int j;
765
        int s = smp[i];
766
        int p0 = 0, p1 = 0;
767
        for(j=0; j<order; j++) {
768
            int c = coefs[j];
769
            p1 += c*s;
770
            s = smp[i-j-1];
771
            p0 += c*s;
772
        }
773
        res[i  ] = smp[i  ] - (p0 >> shift);
774
        res[i+1] = smp[i+1] - (p1 >> shift);
775
    }
776
#else
777
    switch(order) {
778
        case  1: encode_residual_lpc_unrolled(res, smp, n, 1, coefs, shift, 0); break;
779
        case  2: encode_residual_lpc_unrolled(res, smp, n, 2, coefs, shift, 0); break;
780
        case  3: encode_residual_lpc_unrolled(res, smp, n, 3, coefs, shift, 0); break;
781
        case  4: encode_residual_lpc_unrolled(res, smp, n, 4, coefs, shift, 0); break;
782
        case  5: encode_residual_lpc_unrolled(res, smp, n, 5, coefs, shift, 0); break;
783
        case  6: encode_residual_lpc_unrolled(res, smp, n, 6, coefs, shift, 0); break;
784
        case  7: encode_residual_lpc_unrolled(res, smp, n, 7, coefs, shift, 0); break;
785
        case  8: encode_residual_lpc_unrolled(res, smp, n, 8, coefs, shift, 0); break;
786
        default: encode_residual_lpc_unrolled(res, smp, n, order, coefs, shift, 1); break;
787
    }
788
#endif
789
}
790

    
791
static int encode_residual(FlacEncodeContext *ctx, int ch)
792
{
793
    int i, n;
794
    int min_order, max_order, opt_order, precision, omethod;
795
    int min_porder, max_porder;
796
    FlacFrame *frame;
797
    FlacSubframe *sub;
798
    int32_t coefs[MAX_LPC_ORDER][MAX_LPC_ORDER];
799
    int shift[MAX_LPC_ORDER];
800
    int32_t *res, *smp;
801

    
802
    frame = &ctx->frame;
803
    sub = &frame->subframes[ch];
804
    res = sub->residual;
805
    smp = sub->samples;
806
    n = frame->blocksize;
807

    
808
    /* CONSTANT */
809
    for(i=1; i<n; i++) {
810
        if(smp[i] != smp[0]) break;
811
    }
812
    if(i == n) {
813
        sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
814
        res[0] = smp[0];
815
        return sub->obits;
816
    }
817

    
818
    /* VERBATIM */
819
    if(n < 5) {
820
        sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
821
        encode_residual_verbatim(res, smp, n);
822
        return sub->obits * n;
823
    }
824

    
825
    min_order = ctx->options.min_prediction_order;
826
    max_order = ctx->options.max_prediction_order;
827
    min_porder = ctx->options.min_partition_order;
828
    max_porder = ctx->options.max_partition_order;
829
    precision = ctx->options.lpc_coeff_precision;
830
    omethod = ctx->options.prediction_order_method;
831

    
832
    /* FIXED */
833
    if(!ctx->options.use_lpc || max_order == 0 || (n <= max_order)) {
834
        uint32_t bits[MAX_FIXED_ORDER+1];
835
        if(max_order > MAX_FIXED_ORDER) max_order = MAX_FIXED_ORDER;
836
        opt_order = 0;
837
        bits[0] = UINT32_MAX;
838
        for(i=min_order; i<=max_order; i++) {
839
            encode_residual_fixed(res, smp, n, i);
840
            bits[i] = calc_rice_params_fixed(&sub->rc, min_porder, max_porder, res,
841
                                             n, i, sub->obits);
842
            if(bits[i] < bits[opt_order]) {
843
                opt_order = i;
844
            }
845
        }
846
        sub->order = opt_order;
847
        sub->type = FLAC_SUBFRAME_FIXED;
848
        sub->type_code = sub->type | sub->order;
849
        if(sub->order != max_order) {
850
            encode_residual_fixed(res, smp, n, sub->order);
851
            return calc_rice_params_fixed(&sub->rc, min_porder, max_porder, res, n,
852
                                          sub->order, sub->obits);
853
        }
854
        return bits[sub->order];
855
    }
856

    
857
    /* LPC */
858
    opt_order = ff_lpc_calc_coefs(&ctx->dsp, smp, n, min_order, max_order,
859
                                  precision, coefs, shift, ctx->options.use_lpc,
860
                                  omethod, MAX_LPC_SHIFT, 0);
861

    
862
    if(omethod == ORDER_METHOD_2LEVEL ||
863
       omethod == ORDER_METHOD_4LEVEL ||
864
       omethod == ORDER_METHOD_8LEVEL) {
865
        int levels = 1 << omethod;
866
        uint32_t bits[levels];
867
        int order;
868
        int opt_index = levels-1;
869
        opt_order = max_order-1;
870
        bits[opt_index] = UINT32_MAX;
871
        for(i=levels-1; i>=0; i--) {
872
            order = min_order + (((max_order-min_order+1) * (i+1)) / levels)-1;
873
            if(order < 0) order = 0;
874
            encode_residual_lpc(res, smp, n, order+1, coefs[order], shift[order]);
875
            bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
876
                                           res, n, order+1, sub->obits, precision);
877
            if(bits[i] < bits[opt_index]) {
878
                opt_index = i;
879
                opt_order = order;
880
            }
881
        }
882
        opt_order++;
883
    } else if(omethod == ORDER_METHOD_SEARCH) {
884
        // brute-force optimal order search
885
        uint32_t bits[MAX_LPC_ORDER];
886
        opt_order = 0;
887
        bits[0] = UINT32_MAX;
888
        for(i=min_order-1; i<max_order; i++) {
889
            encode_residual_lpc(res, smp, n, i+1, coefs[i], shift[i]);
890
            bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
891
                                           res, n, i+1, sub->obits, precision);
892
            if(bits[i] < bits[opt_order]) {
893
                opt_order = i;
894
            }
895
        }
896
        opt_order++;
897
    } else if(omethod == ORDER_METHOD_LOG) {
898
        uint32_t bits[MAX_LPC_ORDER];
899
        int step;
900

    
901
        opt_order= min_order - 1 + (max_order-min_order)/3;
902
        memset(bits, -1, sizeof(bits));
903

    
904
        for(step=16 ;step; step>>=1){
905
            int last= opt_order;
906
            for(i=last-step; i<=last+step; i+= step){
907
                if(i<min_order-1 || i>=max_order || bits[i] < UINT32_MAX)
908
                    continue;
909
                encode_residual_lpc(res, smp, n, i+1, coefs[i], shift[i]);
910
                bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
911
                                            res, n, i+1, sub->obits, precision);
912
                if(bits[i] < bits[opt_order])
913
                    opt_order= i;
914
            }
915
        }
916
        opt_order++;
917
    }
918

    
919
    sub->order = opt_order;
920
    sub->type = FLAC_SUBFRAME_LPC;
921
    sub->type_code = sub->type | (sub->order-1);
922
    sub->shift = shift[sub->order-1];
923
    for(i=0; i<sub->order; i++) {
924
        sub->coefs[i] = coefs[sub->order-1][i];
925
    }
926
    encode_residual_lpc(res, smp, n, sub->order, sub->coefs, sub->shift);
927
    return calc_rice_params_lpc(&sub->rc, min_porder, max_porder, res, n, sub->order,
928
                                sub->obits, precision);
929
}
930

    
931
static int encode_residual_v(FlacEncodeContext *ctx, int ch)
932
{
933
    int i, n;
934
    FlacFrame *frame;
935
    FlacSubframe *sub;
936
    int32_t *res, *smp;
937

    
938
    frame = &ctx->frame;
939
    sub = &frame->subframes[ch];
940
    res = sub->residual;
941
    smp = sub->samples;
942
    n = frame->blocksize;
943

    
944
    /* CONSTANT */
945
    for(i=1; i<n; i++) {
946
        if(smp[i] != smp[0]) break;
947
    }
948
    if(i == n) {
949
        sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
950
        res[0] = smp[0];
951
        return sub->obits;
952
    }
953

    
954
    /* VERBATIM */
955
    sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
956
    encode_residual_verbatim(res, smp, n);
957
    return sub->obits * n;
958
}
959

    
960
static int estimate_stereo_mode(int32_t *left_ch, int32_t *right_ch, int n)
961
{
962
    int i, best;
963
    int32_t lt, rt;
964
    uint64_t sum[4];
965
    uint64_t score[4];
966
    int k;
967

    
968
    /* calculate sum of 2nd order residual for each channel */
969
    sum[0] = sum[1] = sum[2] = sum[3] = 0;
970
    for(i=2; i<n; i++) {
971
        lt = left_ch[i] - 2*left_ch[i-1] + left_ch[i-2];
972
        rt = right_ch[i] - 2*right_ch[i-1] + right_ch[i-2];
973
        sum[2] += FFABS((lt + rt) >> 1);
974
        sum[3] += FFABS(lt - rt);
975
        sum[0] += FFABS(lt);
976
        sum[1] += FFABS(rt);
977
    }
978
    /* estimate bit counts */
979
    for(i=0; i<4; i++) {
980
        k = find_optimal_param(2*sum[i], n);
981
        sum[i] = rice_encode_count(2*sum[i], n, k);
982
    }
983

    
984
    /* calculate score for each mode */
985
    score[0] = sum[0] + sum[1];
986
    score[1] = sum[0] + sum[3];
987
    score[2] = sum[1] + sum[3];
988
    score[3] = sum[2] + sum[3];
989

    
990
    /* return mode with lowest score */
991
    best = 0;
992
    for(i=1; i<4; i++) {
993
        if(score[i] < score[best]) {
994
            best = i;
995
        }
996
    }
997
    if(best == 0) {
998
        return FLAC_CHMODE_LEFT_RIGHT;
999
    } else if(best == 1) {
1000
        return FLAC_CHMODE_LEFT_SIDE;
1001
    } else if(best == 2) {
1002
        return FLAC_CHMODE_RIGHT_SIDE;
1003
    } else {
1004
        return FLAC_CHMODE_MID_SIDE;
1005
    }
1006
}
1007

    
1008
/**
1009
 * Perform stereo channel decorrelation
1010
 */
1011
static void channel_decorrelation(FlacEncodeContext *ctx)
1012
{
1013
    FlacFrame *frame;
1014
    int32_t *left, *right;
1015
    int i, n;
1016

    
1017
    frame = &ctx->frame;
1018
    n = frame->blocksize;
1019
    left  = frame->subframes[0].samples;
1020
    right = frame->subframes[1].samples;
1021

    
1022
    if(ctx->channels != 2) {
1023
        frame->ch_mode = FLAC_CHMODE_NOT_STEREO;
1024
        return;
1025
    }
1026

    
1027
    frame->ch_mode = estimate_stereo_mode(left, right, n);
1028

    
1029
    /* perform decorrelation and adjust bits-per-sample */
1030
    if(frame->ch_mode == FLAC_CHMODE_LEFT_RIGHT) {
1031
        return;
1032
    }
1033
    if(frame->ch_mode == FLAC_CHMODE_MID_SIDE) {
1034
        int32_t tmp;
1035
        for(i=0; i<n; i++) {
1036
            tmp = left[i];
1037
            left[i] = (tmp + right[i]) >> 1;
1038
            right[i] = tmp - right[i];
1039
        }
1040
        frame->subframes[1].obits++;
1041
    } else if(frame->ch_mode == FLAC_CHMODE_LEFT_SIDE) {
1042
        for(i=0; i<n; i++) {
1043
            right[i] = left[i] - right[i];
1044
        }
1045
        frame->subframes[1].obits++;
1046
    } else {
1047
        for(i=0; i<n; i++) {
1048
            left[i] -= right[i];
1049
        }
1050
        frame->subframes[0].obits++;
1051
    }
1052
}
1053

    
1054
static void write_utf8(PutBitContext *pb, uint32_t val)
1055
{
1056
    uint8_t tmp;
1057
    PUT_UTF8(val, tmp, put_bits(pb, 8, tmp);)
1058
}
1059

    
1060
static void output_frame_header(FlacEncodeContext *s)
1061
{
1062
    FlacFrame *frame;
1063
    int crc;
1064

    
1065
    frame = &s->frame;
1066

    
1067
    put_bits(&s->pb, 16, 0xFFF8);
1068
    put_bits(&s->pb, 4, frame->bs_code[0]);
1069
    put_bits(&s->pb, 4, s->sr_code[0]);
1070
    if(frame->ch_mode == FLAC_CHMODE_NOT_STEREO) {
1071
        put_bits(&s->pb, 4, s->ch_code);
1072
    } else {
1073
        put_bits(&s->pb, 4, frame->ch_mode);
1074
    }
1075
    put_bits(&s->pb, 3, 4); /* bits-per-sample code */
1076
    put_bits(&s->pb, 1, 0);
1077
    write_utf8(&s->pb, s->frame_count);
1078
    if(frame->bs_code[0] == 6) {
1079
        put_bits(&s->pb, 8, frame->bs_code[1]);
1080
    } else if(frame->bs_code[0] == 7) {
1081
        put_bits(&s->pb, 16, frame->bs_code[1]);
1082
    }
1083
    if(s->sr_code[0] == 12) {
1084
        put_bits(&s->pb, 8, s->sr_code[1]);
1085
    } else if(s->sr_code[0] > 12) {
1086
        put_bits(&s->pb, 16, s->sr_code[1]);
1087
    }
1088
    flush_put_bits(&s->pb);
1089
    crc = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
1090
                 s->pb.buf, put_bits_count(&s->pb)>>3);
1091
    put_bits(&s->pb, 8, crc);
1092
}
1093

    
1094
static void output_subframe_constant(FlacEncodeContext *s, int ch)
1095
{
1096
    FlacSubframe *sub;
1097
    int32_t res;
1098

    
1099
    sub = &s->frame.subframes[ch];
1100
    res = sub->residual[0];
1101
    put_sbits(&s->pb, sub->obits, res);
1102
}
1103

    
1104
static void output_subframe_verbatim(FlacEncodeContext *s, int ch)
1105
{
1106
    int i;
1107
    FlacFrame *frame;
1108
    FlacSubframe *sub;
1109
    int32_t res;
1110

    
1111
    frame = &s->frame;
1112
    sub = &frame->subframes[ch];
1113

    
1114
    for(i=0; i<frame->blocksize; i++) {
1115
        res = sub->residual[i];
1116
        put_sbits(&s->pb, sub->obits, res);
1117
    }
1118
}
1119

    
1120
static void output_residual(FlacEncodeContext *ctx, int ch)
1121
{
1122
    int i, j, p, n, parts;
1123
    int k, porder, psize, res_cnt;
1124
    FlacFrame *frame;
1125
    FlacSubframe *sub;
1126
    int32_t *res;
1127

    
1128
    frame = &ctx->frame;
1129
    sub = &frame->subframes[ch];
1130
    res = sub->residual;
1131
    n = frame->blocksize;
1132

    
1133
    /* rice-encoded block */
1134
    put_bits(&ctx->pb, 2, 0);
1135

    
1136
    /* partition order */
1137
    porder = sub->rc.porder;
1138
    psize = n >> porder;
1139
    parts = (1 << porder);
1140
    put_bits(&ctx->pb, 4, porder);
1141
    res_cnt = psize - sub->order;
1142

    
1143
    /* residual */
1144
    j = sub->order;
1145
    for(p=0; p<parts; p++) {
1146
        k = sub->rc.params[p];
1147
        put_bits(&ctx->pb, 4, k);
1148
        if(p == 1) res_cnt = psize;
1149
        for(i=0; i<res_cnt && j<n; i++, j++) {
1150
            set_sr_golomb_flac(&ctx->pb, res[j], k, INT32_MAX, 0);
1151
        }
1152
    }
1153
}
1154

    
1155
static void output_subframe_fixed(FlacEncodeContext *ctx, int ch)
1156
{
1157
    int i;
1158
    FlacFrame *frame;
1159
    FlacSubframe *sub;
1160

    
1161
    frame = &ctx->frame;
1162
    sub = &frame->subframes[ch];
1163

    
1164
    /* warm-up samples */
1165
    for(i=0; i<sub->order; i++) {
1166
        put_sbits(&ctx->pb, sub->obits, sub->residual[i]);
1167
    }
1168

    
1169
    /* residual */
1170
    output_residual(ctx, ch);
1171
}
1172

    
1173
static void output_subframe_lpc(FlacEncodeContext *ctx, int ch)
1174
{
1175
    int i, cbits;
1176
    FlacFrame *frame;
1177
    FlacSubframe *sub;
1178

    
1179
    frame = &ctx->frame;
1180
    sub = &frame->subframes[ch];
1181

    
1182
    /* warm-up samples */
1183
    for(i=0; i<sub->order; i++) {
1184
        put_sbits(&ctx->pb, sub->obits, sub->residual[i]);
1185
    }
1186

    
1187
    /* LPC coefficients */
1188
    cbits = ctx->options.lpc_coeff_precision;
1189
    put_bits(&ctx->pb, 4, cbits-1);
1190
    put_sbits(&ctx->pb, 5, sub->shift);
1191
    for(i=0; i<sub->order; i++) {
1192
        put_sbits(&ctx->pb, cbits, sub->coefs[i]);
1193
    }
1194

    
1195
    /* residual */
1196
    output_residual(ctx, ch);
1197
}
1198

    
1199
static void output_subframes(FlacEncodeContext *s)
1200
{
1201
    FlacFrame *frame;
1202
    FlacSubframe *sub;
1203
    int ch;
1204

    
1205
    frame = &s->frame;
1206

    
1207
    for(ch=0; ch<s->channels; ch++) {
1208
        sub = &frame->subframes[ch];
1209

    
1210
        /* subframe header */
1211
        put_bits(&s->pb, 1, 0);
1212
        put_bits(&s->pb, 6, sub->type_code);
1213
        put_bits(&s->pb, 1, 0); /* no wasted bits */
1214

    
1215
        /* subframe */
1216
        if(sub->type == FLAC_SUBFRAME_CONSTANT) {
1217
            output_subframe_constant(s, ch);
1218
        } else if(sub->type == FLAC_SUBFRAME_VERBATIM) {
1219
            output_subframe_verbatim(s, ch);
1220
        } else if(sub->type == FLAC_SUBFRAME_FIXED) {
1221
            output_subframe_fixed(s, ch);
1222
        } else if(sub->type == FLAC_SUBFRAME_LPC) {
1223
            output_subframe_lpc(s, ch);
1224
        }
1225
    }
1226
}
1227

    
1228
static void output_frame_footer(FlacEncodeContext *s)
1229
{
1230
    int crc;
1231
    flush_put_bits(&s->pb);
1232
    crc = bswap_16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
1233
                          s->pb.buf, put_bits_count(&s->pb)>>3));
1234
    put_bits(&s->pb, 16, crc);
1235
    flush_put_bits(&s->pb);
1236
}
1237

    
1238
static int flac_encode_frame(AVCodecContext *avctx, uint8_t *frame,
1239
                             int buf_size, void *data)
1240
{
1241
    int ch;
1242
    FlacEncodeContext *s;
1243
    int16_t *samples = data;
1244
    int out_bytes;
1245

    
1246
    s = avctx->priv_data;
1247

    
1248
    init_frame(s);
1249

    
1250
    copy_samples(s, samples);
1251

    
1252
    channel_decorrelation(s);
1253

    
1254
    for(ch=0; ch<s->channels; ch++) {
1255
        encode_residual(s, ch);
1256
    }
1257
    init_put_bits(&s->pb, frame, buf_size);
1258
    output_frame_header(s);
1259
    output_subframes(s);
1260
    output_frame_footer(s);
1261
    out_bytes = put_bits_count(&s->pb) >> 3;
1262

    
1263
    if(out_bytes > s->max_framesize || out_bytes >= buf_size) {
1264
        /* frame too large. use verbatim mode */
1265
        for(ch=0; ch<s->channels; ch++) {
1266
            encode_residual_v(s, ch);
1267
        }
1268
        init_put_bits(&s->pb, frame, buf_size);
1269
        output_frame_header(s);
1270
        output_subframes(s);
1271
        output_frame_footer(s);
1272
        out_bytes = put_bits_count(&s->pb) >> 3;
1273

    
1274
        if(out_bytes > s->max_framesize || out_bytes >= buf_size) {
1275
            /* still too large. must be an error. */
1276
            av_log(avctx, AV_LOG_ERROR, "error encoding frame\n");
1277
            return -1;
1278
        }
1279
    }
1280

    
1281
    s->frame_count++;
1282
    return out_bytes;
1283
}
1284

    
1285
static av_cold int flac_encode_close(AVCodecContext *avctx)
1286
{
1287
    av_freep(&avctx->extradata);
1288
    avctx->extradata_size = 0;
1289
    av_freep(&avctx->coded_frame);
1290
    return 0;
1291
}
1292

    
1293
AVCodec flac_encoder = {
1294
    "flac",
1295
    CODEC_TYPE_AUDIO,
1296
    CODEC_ID_FLAC,
1297
    sizeof(FlacEncodeContext),
1298
    flac_encode_init,
1299
    flac_encode_frame,
1300
    flac_encode_close,
1301
    NULL,
1302
    .capabilities = CODEC_CAP_SMALL_LAST_FRAME,
1303
    .sample_fmts = (enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
1304
    .long_name = NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),
1305
};