3 * Copyright (c) 2006 Justin Ruggles <justin.ruggles@gmail.com>
5 * This file is part of FFmpeg.
7 * 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.
12 * 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "libavutil/crc.h"
23 #include "libavutil/lls.h"
24 #include "libavutil/md5.h"
26 #include "bitstream.h"
33 #define FLAC_SUBFRAME_CONSTANT 0
34 #define FLAC_SUBFRAME_VERBATIM 1
35 #define FLAC_SUBFRAME_FIXED 8
36 #define FLAC_SUBFRAME_LPC 32
38 #define MAX_FIXED_ORDER 4
39 #define MAX_PARTITION_ORDER 8
40 #define MAX_PARTITIONS (1 << MAX_PARTITION_ORDER)
41 #define MAX_LPC_PRECISION 15
42 #define MAX_LPC_SHIFT 15
43 #define MAX_RICE_PARAM 14
45 typedef struct CompressionOptions {
46 int compression_level;
49 int lpc_coeff_precision;
50 int min_prediction_order;
51 int max_prediction_order;
52 int prediction_order_method;
53 int min_partition_order;
54 int max_partition_order;
57 typedef struct RiceContext {
59 int params[MAX_PARTITIONS];
62 typedef struct FlacSubframe {
67 int32_t coefs[MAX_LPC_ORDER];
70 int32_t samples[FLAC_MAX_BLOCKSIZE];
71 int32_t residual[FLAC_MAX_BLOCKSIZE+1];
74 typedef struct FlacFrame {
75 FlacSubframe subframes[FLAC_MAX_CHANNELS];
82 typedef struct FlacEncodeContext {
89 int max_encoded_framesize;
91 uint64_t sample_count;
94 CompressionOptions options;
95 AVCodecContext *avctx;
101 * Writes streaminfo metadata block to byte array
103 static void write_streaminfo(FlacEncodeContext *s, uint8_t *header)
107 memset(header, 0, FLAC_STREAMINFO_SIZE);
108 init_put_bits(&pb, header, FLAC_STREAMINFO_SIZE);
110 /* streaminfo metadata block */
111 put_bits(&pb, 16, s->avctx->frame_size);
112 put_bits(&pb, 16, s->avctx->frame_size);
113 put_bits(&pb, 24, s->min_framesize);
114 put_bits(&pb, 24, s->max_framesize);
115 put_bits(&pb, 20, s->samplerate);
116 put_bits(&pb, 3, s->channels-1);
117 put_bits(&pb, 5, 15); /* bits per sample - 1 */
118 /* write 36-bit sample count in 2 put_bits() calls */
119 put_bits(&pb, 24, (s->sample_count & 0xFFFFFF000LL) >> 12);
120 put_bits(&pb, 12, s->sample_count & 0x000000FFFLL);
122 memcpy(&header[18], s->md5sum, 16);
126 * Sets blocksize based on samplerate
127 * Chooses the closest predefined blocksize >= BLOCK_TIME_MS milliseconds
129 static int select_blocksize(int samplerate, int block_time_ms)
135 assert(samplerate > 0);
136 blocksize = ff_flac_blocksize_table[1];
137 target = (samplerate * block_time_ms) / 1000;
138 for(i=0; i<16; i++) {
139 if(target >= ff_flac_blocksize_table[i] && ff_flac_blocksize_table[i] > blocksize) {
140 blocksize = ff_flac_blocksize_table[i];
146 static av_cold int flac_encode_init(AVCodecContext *avctx)
148 int freq = avctx->sample_rate;
149 int channels = avctx->channels;
150 FlacEncodeContext *s = avctx->priv_data;
156 dsputil_init(&s->dsp, avctx);
158 if(avctx->sample_fmt != SAMPLE_FMT_S16) {
162 if(channels < 1 || channels > FLAC_MAX_CHANNELS) {
165 s->channels = channels;
167 /* find samplerate in table */
170 for(i=4; i<12; i++) {
171 if(freq == ff_flac_sample_rate_table[i]) {
172 s->samplerate = ff_flac_sample_rate_table[i];
178 /* if not in table, samplerate is non-standard */
180 if(freq % 1000 == 0 && freq < 255000) {
182 s->sr_code[1] = freq / 1000;
183 } else if(freq % 10 == 0 && freq < 655350) {
185 s->sr_code[1] = freq / 10;
186 } else if(freq < 65535) {
188 s->sr_code[1] = freq;
192 s->samplerate = freq;
195 /* set compression option defaults based on avctx->compression_level */
196 if(avctx->compression_level < 0) {
197 s->options.compression_level = 5;
199 s->options.compression_level = avctx->compression_level;
201 av_log(avctx, AV_LOG_DEBUG, " compression: %d\n", s->options.compression_level);
203 level= s->options.compression_level;
205 av_log(avctx, AV_LOG_ERROR, "invalid compression level: %d\n",
206 s->options.compression_level);
210 s->options.block_time_ms = ((int[]){ 27, 27, 27,105,105,105,105,105,105,105,105,105,105})[level];
211 s->options.use_lpc = ((int[]){ 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1})[level];
212 s->options.min_prediction_order= ((int[]){ 2, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1})[level];
213 s->options.max_prediction_order= ((int[]){ 3, 4, 4, 6, 8, 8, 8, 8, 12, 12, 12, 32, 32})[level];
214 s->options.prediction_order_method = ((int[]){ ORDER_METHOD_EST, ORDER_METHOD_EST, ORDER_METHOD_EST,
215 ORDER_METHOD_EST, ORDER_METHOD_EST, ORDER_METHOD_EST,
216 ORDER_METHOD_4LEVEL, ORDER_METHOD_LOG, ORDER_METHOD_4LEVEL,
217 ORDER_METHOD_LOG, ORDER_METHOD_SEARCH, ORDER_METHOD_LOG,
218 ORDER_METHOD_SEARCH})[level];
219 s->options.min_partition_order = ((int[]){ 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0})[level];
220 s->options.max_partition_order = ((int[]){ 2, 2, 3, 3, 3, 8, 8, 8, 8, 8, 8, 8, 8})[level];
222 /* set compression option overrides from AVCodecContext */
223 if(avctx->use_lpc >= 0) {
224 s->options.use_lpc = av_clip(avctx->use_lpc, 0, 11);
226 if(s->options.use_lpc == 1)
227 av_log(avctx, AV_LOG_DEBUG, " use lpc: Levinson-Durbin recursion with Welch window\n");
228 else if(s->options.use_lpc > 1)
229 av_log(avctx, AV_LOG_DEBUG, " use lpc: Cholesky factorization\n");
231 if(avctx->min_prediction_order >= 0) {
232 if(s->options.use_lpc) {
233 if(avctx->min_prediction_order < MIN_LPC_ORDER ||
234 avctx->min_prediction_order > MAX_LPC_ORDER) {
235 av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
236 avctx->min_prediction_order);
240 if(avctx->min_prediction_order > MAX_FIXED_ORDER) {
241 av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
242 avctx->min_prediction_order);
246 s->options.min_prediction_order = avctx->min_prediction_order;
248 if(avctx->max_prediction_order >= 0) {
249 if(s->options.use_lpc) {
250 if(avctx->max_prediction_order < MIN_LPC_ORDER ||
251 avctx->max_prediction_order > MAX_LPC_ORDER) {
252 av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
253 avctx->max_prediction_order);
257 if(avctx->max_prediction_order > MAX_FIXED_ORDER) {
258 av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
259 avctx->max_prediction_order);
263 s->options.max_prediction_order = avctx->max_prediction_order;
265 if(s->options.max_prediction_order < s->options.min_prediction_order) {
266 av_log(avctx, AV_LOG_ERROR, "invalid prediction orders: min=%d max=%d\n",
267 s->options.min_prediction_order, s->options.max_prediction_order);
270 av_log(avctx, AV_LOG_DEBUG, " prediction order: %d, %d\n",
271 s->options.min_prediction_order, s->options.max_prediction_order);
273 if(avctx->prediction_order_method >= 0) {
274 if(avctx->prediction_order_method > ORDER_METHOD_LOG) {
275 av_log(avctx, AV_LOG_ERROR, "invalid prediction order method: %d\n",
276 avctx->prediction_order_method);
279 s->options.prediction_order_method = avctx->prediction_order_method;
281 switch(s->options.prediction_order_method) {
282 case ORDER_METHOD_EST: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
284 case ORDER_METHOD_2LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
286 case ORDER_METHOD_4LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
288 case ORDER_METHOD_8LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
290 case ORDER_METHOD_SEARCH: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
291 "full search"); break;
292 case ORDER_METHOD_LOG: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
293 "log search"); break;
296 if(avctx->min_partition_order >= 0) {
297 if(avctx->min_partition_order > MAX_PARTITION_ORDER) {
298 av_log(avctx, AV_LOG_ERROR, "invalid min partition order: %d\n",
299 avctx->min_partition_order);
302 s->options.min_partition_order = avctx->min_partition_order;
304 if(avctx->max_partition_order >= 0) {
305 if(avctx->max_partition_order > MAX_PARTITION_ORDER) {
306 av_log(avctx, AV_LOG_ERROR, "invalid max partition order: %d\n",
307 avctx->max_partition_order);
310 s->options.max_partition_order = avctx->max_partition_order;
312 if(s->options.max_partition_order < s->options.min_partition_order) {
313 av_log(avctx, AV_LOG_ERROR, "invalid partition orders: min=%d max=%d\n",
314 s->options.min_partition_order, s->options.max_partition_order);
317 av_log(avctx, AV_LOG_DEBUG, " partition order: %d, %d\n",
318 s->options.min_partition_order, s->options.max_partition_order);
320 if(avctx->frame_size > 0) {
321 if(avctx->frame_size < FLAC_MIN_BLOCKSIZE ||
322 avctx->frame_size > FLAC_MAX_BLOCKSIZE) {
323 av_log(avctx, AV_LOG_ERROR, "invalid block size: %d\n",
328 s->avctx->frame_size = select_blocksize(s->samplerate, s->options.block_time_ms);
330 av_log(avctx, AV_LOG_DEBUG, " block size: %d\n", s->avctx->frame_size);
332 /* set LPC precision */
333 if(avctx->lpc_coeff_precision > 0) {
334 if(avctx->lpc_coeff_precision > MAX_LPC_PRECISION) {
335 av_log(avctx, AV_LOG_ERROR, "invalid lpc coeff precision: %d\n",
336 avctx->lpc_coeff_precision);
339 s->options.lpc_coeff_precision = avctx->lpc_coeff_precision;
341 /* default LPC precision */
342 s->options.lpc_coeff_precision = 15;
344 av_log(avctx, AV_LOG_DEBUG, " lpc precision: %d\n",
345 s->options.lpc_coeff_precision);
347 /* set maximum encoded frame size in verbatim mode */
348 s->max_framesize = ff_flac_get_max_frame_size(s->avctx->frame_size,
351 /* initialize MD5 context */
352 s->md5ctx = av_malloc(av_md5_size);
354 return AVERROR_NOMEM;
355 av_md5_init(s->md5ctx);
357 streaminfo = av_malloc(FLAC_STREAMINFO_SIZE);
358 write_streaminfo(s, streaminfo);
359 avctx->extradata = streaminfo;
360 avctx->extradata_size = FLAC_STREAMINFO_SIZE;
363 s->min_framesize = s->max_framesize;
365 avctx->coded_frame = avcodec_alloc_frame();
366 avctx->coded_frame->key_frame = 1;
371 static void init_frame(FlacEncodeContext *s)
378 for(i=0; i<16; i++) {
379 if(s->avctx->frame_size == ff_flac_blocksize_table[i]) {
380 frame->blocksize = ff_flac_blocksize_table[i];
381 frame->bs_code[0] = i;
382 frame->bs_code[1] = 0;
387 frame->blocksize = s->avctx->frame_size;
388 if(frame->blocksize <= 256) {
389 frame->bs_code[0] = 6;
390 frame->bs_code[1] = frame->blocksize-1;
392 frame->bs_code[0] = 7;
393 frame->bs_code[1] = frame->blocksize-1;
397 for(ch=0; ch<s->channels; ch++) {
398 frame->subframes[ch].obits = 16;
403 * Copy channel-interleaved input samples into separate subframes
405 static void copy_samples(FlacEncodeContext *s, int16_t *samples)
411 for(i=0,j=0; i<frame->blocksize; i++) {
412 for(ch=0; ch<s->channels; ch++,j++) {
413 frame->subframes[ch].samples[i] = samples[j];
419 #define rice_encode_count(sum, n, k) (((n)*((k)+1))+((sum-(n>>1))>>(k)))
422 * Solve for d/dk(rice_encode_count) = n-((sum-(n>>1))>>(k+1)) = 0
424 static int find_optimal_param(uint32_t sum, int n)
432 k = av_log2(n<256 ? FASTDIV(sum2,n) : sum2/n);
433 return FFMIN(k, MAX_RICE_PARAM);
436 static uint32_t calc_optimal_rice_params(RiceContext *rc, int porder,
437 uint32_t *sums, int n, int pred_order)
443 part = (1 << porder);
446 cnt = (n >> porder) - pred_order;
447 for(i=0; i<part; i++) {
448 k = find_optimal_param(sums[i], cnt);
450 all_bits += rice_encode_count(sums[i], cnt, k);
459 static void calc_sums(int pmin, int pmax, uint32_t *data, int n, int pred_order,
460 uint32_t sums[][MAX_PARTITIONS])
464 uint32_t *res, *res_end;
466 /* sums for highest level */
468 res = &data[pred_order];
469 res_end = &data[n >> pmax];
470 for(i=0; i<parts; i++) {
472 while(res < res_end){
478 /* sums for lower levels */
479 for(i=pmax-1; i>=pmin; i--) {
481 for(j=0; j<parts; j++) {
482 sums[i][j] = sums[i+1][2*j] + sums[i+1][2*j+1];
487 static uint32_t calc_rice_params(RiceContext *rc, int pmin, int pmax,
488 int32_t *data, int n, int pred_order)
491 uint32_t bits[MAX_PARTITION_ORDER+1];
495 uint32_t sums[MAX_PARTITION_ORDER+1][MAX_PARTITIONS];
497 assert(pmin >= 0 && pmin <= MAX_PARTITION_ORDER);
498 assert(pmax >= 0 && pmax <= MAX_PARTITION_ORDER);
499 assert(pmin <= pmax);
501 udata = av_malloc(n * sizeof(uint32_t));
503 udata[i] = (2*data[i]) ^ (data[i]>>31);
506 calc_sums(pmin, pmax, udata, n, pred_order, sums);
509 bits[pmin] = UINT32_MAX;
510 for(i=pmin; i<=pmax; i++) {
511 bits[i] = calc_optimal_rice_params(&tmp_rc, i, sums[i], n, pred_order);
512 if(bits[i] <= bits[opt_porder]) {
519 return bits[opt_porder];
522 static int get_max_p_order(int max_porder, int n, int order)
524 int porder = FFMIN(max_porder, av_log2(n^(n-1)));
526 porder = FFMIN(porder, av_log2(n/order));
530 static uint32_t calc_rice_params_fixed(RiceContext *rc, int pmin, int pmax,
531 int32_t *data, int n, int pred_order,
535 pmin = get_max_p_order(pmin, n, pred_order);
536 pmax = get_max_p_order(pmax, n, pred_order);
537 bits = pred_order*bps + 6;
538 bits += calc_rice_params(rc, pmin, pmax, data, n, pred_order);
542 static uint32_t calc_rice_params_lpc(RiceContext *rc, int pmin, int pmax,
543 int32_t *data, int n, int pred_order,
544 int bps, int precision)
547 pmin = get_max_p_order(pmin, n, pred_order);
548 pmax = get_max_p_order(pmax, n, pred_order);
549 bits = pred_order*bps + 4 + 5 + pred_order*precision + 6;
550 bits += calc_rice_params(rc, pmin, pmax, data, n, pred_order);
555 * Apply Welch window function to audio block
557 static void apply_welch_window(const int32_t *data, int len, double *w_data)
563 assert(!(len&1)); //the optimization in r11881 does not support odd len
564 //if someone wants odd len extend the change in r11881
567 c = 2.0 / (len - 1.0);
571 for(i=0; i<n2; i++) {
574 w_data[-i-1] = data[-i-1] * w;
575 w_data[+i ] = data[+i ] * w;
580 * Calculates autocorrelation data from audio samples
581 * A Welch window function is applied before calculation.
583 void ff_flac_compute_autocorr(const int32_t *data, int len, int lag,
587 double tmp[len + lag + 1];
588 double *data1= tmp + lag;
590 apply_welch_window(data, len, data1);
596 for(j=0; j<lag; j+=2){
597 double sum0 = 1.0, sum1 = 1.0;
598 for(i=0; i<len; i++){
599 sum0 += data1[i] * data1[i-j];
600 sum1 += data1[i] * data1[i-j-1];
608 for(i=0; i<len; i+=2){
609 sum += data1[i ] * data1[i-j ]
610 + data1[i+1] * data1[i-j+1];
617 static void encode_residual_verbatim(int32_t *res, int32_t *smp, int n)
620 memcpy(res, smp, n * sizeof(int32_t));
623 static void encode_residual_fixed(int32_t *res, const int32_t *smp, int n,
628 for(i=0; i<order; i++) {
633 for(i=order; i<n; i++)
636 for(i=order; i<n; i++)
637 res[i]= smp[i] - smp[i-1];
639 int a = smp[order-1] - smp[order-2];
640 for(i=order; i<n; i+=2) {
641 int b = smp[i] - smp[i-1];
643 a = smp[i+1] - smp[i];
647 int a = smp[order-1] - smp[order-2];
648 int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
649 for(i=order; i<n; i+=2) {
650 int b = smp[i] - smp[i-1];
653 a = smp[i+1] - smp[i];
658 int a = smp[order-1] - smp[order-2];
659 int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
660 int e = smp[order-1] - 3*smp[order-2] + 3*smp[order-3] - smp[order-4];
661 for(i=order; i<n; i+=2) {
662 int b = smp[i] - smp[i-1];
666 a = smp[i+1] - smp[i];
675 int c = coefs[(x)-1];\
681 static av_always_inline void encode_residual_lpc_unrolled(
682 int32_t *res, const int32_t *smp, int n,
683 int order, const int32_t *coefs, int shift, int big)
686 for(i=order; i<n; i+=2) {
687 int s = smp[i-order];
736 res[i ] = smp[i ] - (p0 >> shift);
737 res[i+1] = smp[i+1] - (p1 >> shift);
741 static void encode_residual_lpc(int32_t *res, const int32_t *smp, int n,
742 int order, const int32_t *coefs, int shift)
745 for(i=0; i<order; i++) {
749 for(i=order; i<n; i+=2) {
753 for(j=0; j<order; j++) {
759 res[i ] = smp[i ] - (p0 >> shift);
760 res[i+1] = smp[i+1] - (p1 >> shift);
764 case 1: encode_residual_lpc_unrolled(res, smp, n, 1, coefs, shift, 0); break;
765 case 2: encode_residual_lpc_unrolled(res, smp, n, 2, coefs, shift, 0); break;
766 case 3: encode_residual_lpc_unrolled(res, smp, n, 3, coefs, shift, 0); break;
767 case 4: encode_residual_lpc_unrolled(res, smp, n, 4, coefs, shift, 0); break;
768 case 5: encode_residual_lpc_unrolled(res, smp, n, 5, coefs, shift, 0); break;
769 case 6: encode_residual_lpc_unrolled(res, smp, n, 6, coefs, shift, 0); break;
770 case 7: encode_residual_lpc_unrolled(res, smp, n, 7, coefs, shift, 0); break;
771 case 8: encode_residual_lpc_unrolled(res, smp, n, 8, coefs, shift, 0); break;
772 default: encode_residual_lpc_unrolled(res, smp, n, order, coefs, shift, 1); break;
777 static int encode_residual(FlacEncodeContext *ctx, int ch)
780 int min_order, max_order, opt_order, precision, omethod;
781 int min_porder, max_porder;
784 int32_t coefs[MAX_LPC_ORDER][MAX_LPC_ORDER];
785 int shift[MAX_LPC_ORDER];
789 sub = &frame->subframes[ch];
792 n = frame->blocksize;
796 if(smp[i] != smp[0]) break;
799 sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
806 sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
807 encode_residual_verbatim(res, smp, n);
808 return sub->obits * n;
811 min_order = ctx->options.min_prediction_order;
812 max_order = ctx->options.max_prediction_order;
813 min_porder = ctx->options.min_partition_order;
814 max_porder = ctx->options.max_partition_order;
815 precision = ctx->options.lpc_coeff_precision;
816 omethod = ctx->options.prediction_order_method;
819 if(!ctx->options.use_lpc || max_order == 0 || (n <= max_order)) {
820 uint32_t bits[MAX_FIXED_ORDER+1];
821 if(max_order > MAX_FIXED_ORDER) max_order = MAX_FIXED_ORDER;
823 bits[0] = UINT32_MAX;
824 for(i=min_order; i<=max_order; i++) {
825 encode_residual_fixed(res, smp, n, i);
826 bits[i] = calc_rice_params_fixed(&sub->rc, min_porder, max_porder, res,
828 if(bits[i] < bits[opt_order]) {
832 sub->order = opt_order;
833 sub->type = FLAC_SUBFRAME_FIXED;
834 sub->type_code = sub->type | sub->order;
835 if(sub->order != max_order) {
836 encode_residual_fixed(res, smp, n, sub->order);
837 return calc_rice_params_fixed(&sub->rc, min_porder, max_porder, res, n,
838 sub->order, sub->obits);
840 return bits[sub->order];
844 opt_order = ff_lpc_calc_coefs(&ctx->dsp, smp, n, min_order, max_order,
845 precision, coefs, shift, ctx->options.use_lpc,
846 omethod, MAX_LPC_SHIFT, 0);
848 if(omethod == ORDER_METHOD_2LEVEL ||
849 omethod == ORDER_METHOD_4LEVEL ||
850 omethod == ORDER_METHOD_8LEVEL) {
851 int levels = 1 << omethod;
852 uint32_t bits[levels];
854 int opt_index = levels-1;
855 opt_order = max_order-1;
856 bits[opt_index] = UINT32_MAX;
857 for(i=levels-1; i>=0; i--) {
858 order = min_order + (((max_order-min_order+1) * (i+1)) / levels)-1;
859 if(order < 0) order = 0;
860 encode_residual_lpc(res, smp, n, order+1, coefs[order], shift[order]);
861 bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
862 res, n, order+1, sub->obits, precision);
863 if(bits[i] < bits[opt_index]) {
869 } else if(omethod == ORDER_METHOD_SEARCH) {
870 // brute-force optimal order search
871 uint32_t bits[MAX_LPC_ORDER];
873 bits[0] = UINT32_MAX;
874 for(i=min_order-1; i<max_order; i++) {
875 encode_residual_lpc(res, smp, n, i+1, coefs[i], shift[i]);
876 bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
877 res, n, i+1, sub->obits, precision);
878 if(bits[i] < bits[opt_order]) {
883 } else if(omethod == ORDER_METHOD_LOG) {
884 uint32_t bits[MAX_LPC_ORDER];
887 opt_order= min_order - 1 + (max_order-min_order)/3;
888 memset(bits, -1, sizeof(bits));
890 for(step=16 ;step; step>>=1){
892 for(i=last-step; i<=last+step; i+= step){
893 if(i<min_order-1 || i>=max_order || bits[i] < UINT32_MAX)
895 encode_residual_lpc(res, smp, n, i+1, coefs[i], shift[i]);
896 bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
897 res, n, i+1, sub->obits, precision);
898 if(bits[i] < bits[opt_order])
905 sub->order = opt_order;
906 sub->type = FLAC_SUBFRAME_LPC;
907 sub->type_code = sub->type | (sub->order-1);
908 sub->shift = shift[sub->order-1];
909 for(i=0; i<sub->order; i++) {
910 sub->coefs[i] = coefs[sub->order-1][i];
912 encode_residual_lpc(res, smp, n, sub->order, sub->coefs, sub->shift);
913 return calc_rice_params_lpc(&sub->rc, min_porder, max_porder, res, n, sub->order,
914 sub->obits, precision);
917 static int encode_residual_v(FlacEncodeContext *ctx, int ch)
925 sub = &frame->subframes[ch];
928 n = frame->blocksize;
932 if(smp[i] != smp[0]) break;
935 sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
941 sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
942 encode_residual_verbatim(res, smp, n);
943 return sub->obits * n;
946 static int estimate_stereo_mode(int32_t *left_ch, int32_t *right_ch, int n)
954 /* calculate sum of 2nd order residual for each channel */
955 sum[0] = sum[1] = sum[2] = sum[3] = 0;
957 lt = left_ch[i] - 2*left_ch[i-1] + left_ch[i-2];
958 rt = right_ch[i] - 2*right_ch[i-1] + right_ch[i-2];
959 sum[2] += FFABS((lt + rt) >> 1);
960 sum[3] += FFABS(lt - rt);
964 /* estimate bit counts */
966 k = find_optimal_param(2*sum[i], n);
967 sum[i] = rice_encode_count(2*sum[i], n, k);
970 /* calculate score for each mode */
971 score[0] = sum[0] + sum[1];
972 score[1] = sum[0] + sum[3];
973 score[2] = sum[1] + sum[3];
974 score[3] = sum[2] + sum[3];
976 /* return mode with lowest score */
979 if(score[i] < score[best]) {
984 return FLAC_CHMODE_INDEPENDENT;
985 } else if(best == 1) {
986 return FLAC_CHMODE_LEFT_SIDE;
987 } else if(best == 2) {
988 return FLAC_CHMODE_RIGHT_SIDE;
990 return FLAC_CHMODE_MID_SIDE;
995 * Perform stereo channel decorrelation
997 static void channel_decorrelation(FlacEncodeContext *ctx)
1000 int32_t *left, *right;
1003 frame = &ctx->frame;
1004 n = frame->blocksize;
1005 left = frame->subframes[0].samples;
1006 right = frame->subframes[1].samples;
1008 if(ctx->channels != 2) {
1009 frame->ch_mode = FLAC_CHMODE_INDEPENDENT;
1013 frame->ch_mode = estimate_stereo_mode(left, right, n);
1015 /* perform decorrelation and adjust bits-per-sample */
1016 if(frame->ch_mode == FLAC_CHMODE_INDEPENDENT) {
1019 if(frame->ch_mode == FLAC_CHMODE_MID_SIDE) {
1021 for(i=0; i<n; i++) {
1023 left[i] = (tmp + right[i]) >> 1;
1024 right[i] = tmp - right[i];
1026 frame->subframes[1].obits++;
1027 } else if(frame->ch_mode == FLAC_CHMODE_LEFT_SIDE) {
1028 for(i=0; i<n; i++) {
1029 right[i] = left[i] - right[i];
1031 frame->subframes[1].obits++;
1033 for(i=0; i<n; i++) {
1034 left[i] -= right[i];
1036 frame->subframes[0].obits++;
1040 static void write_utf8(PutBitContext *pb, uint32_t val)
1043 PUT_UTF8(val, tmp, put_bits(pb, 8, tmp);)
1046 static void output_frame_header(FlacEncodeContext *s)
1053 put_bits(&s->pb, 16, 0xFFF8);
1054 put_bits(&s->pb, 4, frame->bs_code[0]);
1055 put_bits(&s->pb, 4, s->sr_code[0]);
1056 if(frame->ch_mode == FLAC_CHMODE_INDEPENDENT) {
1057 put_bits(&s->pb, 4, s->channels-1);
1059 put_bits(&s->pb, 4, frame->ch_mode);
1061 put_bits(&s->pb, 3, 4); /* bits-per-sample code */
1062 put_bits(&s->pb, 1, 0);
1063 write_utf8(&s->pb, s->frame_count);
1064 if(frame->bs_code[0] == 6) {
1065 put_bits(&s->pb, 8, frame->bs_code[1]);
1066 } else if(frame->bs_code[0] == 7) {
1067 put_bits(&s->pb, 16, frame->bs_code[1]);
1069 if(s->sr_code[0] == 12) {
1070 put_bits(&s->pb, 8, s->sr_code[1]);
1071 } else if(s->sr_code[0] > 12) {
1072 put_bits(&s->pb, 16, s->sr_code[1]);
1074 flush_put_bits(&s->pb);
1075 crc = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
1076 s->pb.buf, put_bits_count(&s->pb)>>3);
1077 put_bits(&s->pb, 8, crc);
1080 static void output_subframe_constant(FlacEncodeContext *s, int ch)
1085 sub = &s->frame.subframes[ch];
1086 res = sub->residual[0];
1087 put_sbits(&s->pb, sub->obits, res);
1090 static void output_subframe_verbatim(FlacEncodeContext *s, int ch)
1098 sub = &frame->subframes[ch];
1100 for(i=0; i<frame->blocksize; i++) {
1101 res = sub->residual[i];
1102 put_sbits(&s->pb, sub->obits, res);
1106 static void output_residual(FlacEncodeContext *ctx, int ch)
1108 int i, j, p, n, parts;
1109 int k, porder, psize, res_cnt;
1114 frame = &ctx->frame;
1115 sub = &frame->subframes[ch];
1116 res = sub->residual;
1117 n = frame->blocksize;
1119 /* rice-encoded block */
1120 put_bits(&ctx->pb, 2, 0);
1122 /* partition order */
1123 porder = sub->rc.porder;
1124 psize = n >> porder;
1125 parts = (1 << porder);
1126 put_bits(&ctx->pb, 4, porder);
1127 res_cnt = psize - sub->order;
1131 for(p=0; p<parts; p++) {
1132 k = sub->rc.params[p];
1133 put_bits(&ctx->pb, 4, k);
1134 if(p == 1) res_cnt = psize;
1135 for(i=0; i<res_cnt && j<n; i++, j++) {
1136 set_sr_golomb_flac(&ctx->pb, res[j], k, INT32_MAX, 0);
1141 static void output_subframe_fixed(FlacEncodeContext *ctx, int ch)
1147 frame = &ctx->frame;
1148 sub = &frame->subframes[ch];
1150 /* warm-up samples */
1151 for(i=0; i<sub->order; i++) {
1152 put_sbits(&ctx->pb, sub->obits, sub->residual[i]);
1156 output_residual(ctx, ch);
1159 static void output_subframe_lpc(FlacEncodeContext *ctx, int ch)
1165 frame = &ctx->frame;
1166 sub = &frame->subframes[ch];
1168 /* warm-up samples */
1169 for(i=0; i<sub->order; i++) {
1170 put_sbits(&ctx->pb, sub->obits, sub->residual[i]);
1173 /* LPC coefficients */
1174 cbits = ctx->options.lpc_coeff_precision;
1175 put_bits(&ctx->pb, 4, cbits-1);
1176 put_sbits(&ctx->pb, 5, sub->shift);
1177 for(i=0; i<sub->order; i++) {
1178 put_sbits(&ctx->pb, cbits, sub->coefs[i]);
1182 output_residual(ctx, ch);
1185 static void output_subframes(FlacEncodeContext *s)
1193 for(ch=0; ch<s->channels; ch++) {
1194 sub = &frame->subframes[ch];
1196 /* subframe header */
1197 put_bits(&s->pb, 1, 0);
1198 put_bits(&s->pb, 6, sub->type_code);
1199 put_bits(&s->pb, 1, 0); /* no wasted bits */
1202 if(sub->type == FLAC_SUBFRAME_CONSTANT) {
1203 output_subframe_constant(s, ch);
1204 } else if(sub->type == FLAC_SUBFRAME_VERBATIM) {
1205 output_subframe_verbatim(s, ch);
1206 } else if(sub->type == FLAC_SUBFRAME_FIXED) {
1207 output_subframe_fixed(s, ch);
1208 } else if(sub->type == FLAC_SUBFRAME_LPC) {
1209 output_subframe_lpc(s, ch);
1214 static void output_frame_footer(FlacEncodeContext *s)
1217 flush_put_bits(&s->pb);
1218 crc = bswap_16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
1219 s->pb.buf, put_bits_count(&s->pb)>>3));
1220 put_bits(&s->pb, 16, crc);
1221 flush_put_bits(&s->pb);
1224 static void update_md5_sum(FlacEncodeContext *s, int16_t *samples)
1226 #ifdef WORDS_BIGENDIAN
1228 for(i = 0; i < s->frame.blocksize*s->channels; i++) {
1229 int16_t smp = le2me_16(samples[i]);
1230 av_md5_update(s->md5ctx, (uint8_t *)&smp, 2);
1233 av_md5_update(s->md5ctx, (uint8_t *)samples, s->frame.blocksize*s->channels*2);
1237 static int flac_encode_frame(AVCodecContext *avctx, uint8_t *frame,
1238 int buf_size, void *data)
1241 FlacEncodeContext *s;
1242 int16_t *samples = data;
1246 s = avctx->priv_data;
1248 if(buf_size < s->max_framesize*2) {
1249 av_log(avctx, AV_LOG_ERROR, "output buffer too small\n");
1253 /* when the last block is reached, update the header in extradata */
1255 s->max_framesize = s->max_encoded_framesize;
1256 av_md5_final(s->md5ctx, s->md5sum);
1257 write_streaminfo(s, avctx->extradata);
1263 copy_samples(s, samples);
1265 channel_decorrelation(s);
1267 for(ch=0; ch<s->channels; ch++) {
1268 encode_residual(s, ch);
1272 init_put_bits(&s->pb, frame, buf_size);
1273 output_frame_header(s);
1274 output_subframes(s);
1275 output_frame_footer(s);
1276 out_bytes = put_bits_count(&s->pb) >> 3;
1278 if(out_bytes > s->max_framesize) {
1280 /* still too large. must be an error. */
1281 av_log(avctx, AV_LOG_ERROR, "error encoding frame\n");
1285 /* frame too large. use verbatim mode */
1286 for(ch=0; ch<s->channels; ch++) {
1287 encode_residual_v(s, ch);
1294 s->sample_count += avctx->frame_size;
1295 update_md5_sum(s, samples);
1296 if (out_bytes > s->max_encoded_framesize)
1297 s->max_encoded_framesize = out_bytes;
1298 if (out_bytes < s->min_framesize)
1299 s->min_framesize = out_bytes;
1304 static av_cold int flac_encode_close(AVCodecContext *avctx)
1306 if (avctx->priv_data) {
1307 FlacEncodeContext *s = avctx->priv_data;
1308 av_freep(&s->md5ctx);
1310 av_freep(&avctx->extradata);
1311 avctx->extradata_size = 0;
1312 av_freep(&avctx->coded_frame);
1316 AVCodec flac_encoder = {
1320 sizeof(FlacEncodeContext),
1325 .capabilities = CODEC_CAP_SMALL_LAST_FRAME | CODEC_CAP_DELAY,
1326 .sample_fmts = (enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
1327 .long_name = NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),