mirror of
https://github.com/FFmpeg/FFmpeg.git
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1e5707b7b8
Originally committed as revision 5593 to svn://svn.ffmpeg.org/ffmpeg/trunk
1268 lines
35 KiB
C
1268 lines
35 KiB
C
/**
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* FLAC audio encoder
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* Copyright (c) 2006 Justin Ruggles <jruggle@earthlink.net>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; 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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*/
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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 "golomb.h"
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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
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#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
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#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 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 FLAC_STREAMINFO_SIZE 34
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#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
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typedef struct CompressionOptions {
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int compression_level;
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int block_time_ms;
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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;
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} CompressionOptions;
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typedef struct RiceContext {
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int porder;
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int params[MAX_PARTITIONS];
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} RiceContext;
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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];
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} FlacSubframe;
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typedef struct FlacFrame {
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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;
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} FlacFrame;
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typedef struct FlacEncodeContext {
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PutBitContext pb;
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int channels;
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int ch_code;
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int samplerate;
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int sr_code[2];
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int blocksize;
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int max_framesize;
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uint32_t frame_count;
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FlacFrame frame;
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CompressionOptions options;
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AVCodecContext *avctx;
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} FlacEncodeContext;
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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
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};
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static const int flac_blocksizes[16] = {
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0,
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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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};
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/**
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* Writes streaminfo metadata block to byte array
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*/
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static void write_streaminfo(FlacEncodeContext *s, uint8_t *header)
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{
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PutBitContext pb;
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memset(header, 0, FLAC_STREAMINFO_SIZE);
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init_put_bits(&pb, header, FLAC_STREAMINFO_SIZE);
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/* streaminfo metadata block */
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put_bits(&pb, 16, s->blocksize);
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put_bits(&pb, 16, s->blocksize);
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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);
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/* total samples = 0 */
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/* MD5 signature = 0 */
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}
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/**
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* Sets blocksize based on samplerate
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* Chooses the closest predefined blocksize >= BLOCK_TIME_MS milliseconds
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*/
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static int select_blocksize(int samplerate, int block_time_ms)
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{
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int i;
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int target;
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int blocksize;
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assert(samplerate > 0);
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blocksize = flac_blocksizes[1];
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target = (samplerate * block_time_ms) / 1000;
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for(i=0; i<16; i++) {
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if(target >= flac_blocksizes[i] && flac_blocksizes[i] > blocksize) {
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blocksize = flac_blocksizes[i];
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}
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}
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return blocksize;
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}
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static int flac_encode_init(AVCodecContext *avctx)
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{
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int freq = avctx->sample_rate;
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int channels = avctx->channels;
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FlacEncodeContext *s = avctx->priv_data;
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int i, level;
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uint8_t *streaminfo;
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s->avctx = avctx;
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if(avctx->sample_fmt != SAMPLE_FMT_S16) {
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return -1;
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}
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if(channels < 1 || channels > FLAC_MAX_CH) {
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return -1;
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}
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s->channels = channels;
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s->ch_code = s->channels-1;
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/* find samplerate in table */
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if(freq < 1)
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return -1;
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for(i=4; i<12; i++) {
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if(freq == flac_samplerates[i]) {
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s->samplerate = flac_samplerates[i];
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s->sr_code[0] = i;
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s->sr_code[1] = 0;
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break;
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}
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}
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/* if not in table, samplerate is non-standard */
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if(i == 12) {
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if(freq % 1000 == 0 && freq < 255000) {
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s->sr_code[0] = 12;
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s->sr_code[1] = freq / 1000;
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} else if(freq % 10 == 0 && freq < 655350) {
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s->sr_code[0] = 14;
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s->sr_code[1] = freq / 10;
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} else if(freq < 65535) {
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s->sr_code[0] = 13;
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s->sr_code[1] = freq;
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} else {
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return -1;
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}
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s->samplerate = freq;
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}
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/* set compression option defaults based on avctx->compression_level */
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if(avctx->compression_level < 0) {
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s->options.compression_level = 5;
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} else {
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s->options.compression_level = avctx->compression_level;
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}
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av_log(avctx, AV_LOG_DEBUG, " compression: %d\n", s->options.compression_level);
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level= s->options.compression_level;
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if(level > 5) {
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av_log(avctx, AV_LOG_ERROR, "invalid compression level: %d\n",
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s->options.compression_level);
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return -1;
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}
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s->options.block_time_ms = ((int[]){ 27, 27, 27,105,105,105})[level];
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s->options.use_lpc = ((int[]){ 0, 0, 0, 1, 1, 1})[level];
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s->options.min_prediction_order= ((int[]){ 2, 0, 0, 1, 1, 1})[level];
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s->options.max_prediction_order= ((int[]){ 3, 4, 4, 6, 8, 8})[level];
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s->options.prediction_order_method = ORDER_METHOD_EST;
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s->options.min_partition_order = ((int[]){ 2, 2, 0, 0, 0, 0})[level];
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s->options.max_partition_order = ((int[]){ 2, 2, 3, 3, 3, 8})[level];
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/* set compression option overrides from AVCodecContext */
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if(avctx->use_lpc >= 0) {
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s->options.use_lpc = !!avctx->use_lpc;
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}
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av_log(avctx, AV_LOG_DEBUG, " use lpc: %s\n",
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s->options.use_lpc? "yes" : "no");
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if(avctx->min_prediction_order >= 0) {
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if(s->options.use_lpc) {
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if(avctx->min_prediction_order < MIN_LPC_ORDER ||
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avctx->min_prediction_order > MAX_LPC_ORDER) {
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av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
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avctx->min_prediction_order);
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return -1;
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}
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} else {
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if(avctx->min_prediction_order > MAX_FIXED_ORDER) {
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av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
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avctx->min_prediction_order);
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return -1;
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}
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}
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s->options.min_prediction_order = avctx->min_prediction_order;
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}
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if(avctx->max_prediction_order >= 0) {
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if(s->options.use_lpc) {
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if(avctx->max_prediction_order < MIN_LPC_ORDER ||
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avctx->max_prediction_order > MAX_LPC_ORDER) {
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av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
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avctx->max_prediction_order);
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return -1;
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}
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} else {
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if(avctx->max_prediction_order > MAX_FIXED_ORDER) {
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av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
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avctx->max_prediction_order);
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return -1;
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}
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}
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s->options.max_prediction_order = avctx->max_prediction_order;
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}
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if(s->options.max_prediction_order < s->options.min_prediction_order) {
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av_log(avctx, AV_LOG_ERROR, "invalid prediction orders: min=%d max=%d\n",
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s->options.min_prediction_order, s->options.max_prediction_order);
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return -1;
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}
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av_log(avctx, AV_LOG_DEBUG, " prediction order: %d, %d\n",
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s->options.min_prediction_order, s->options.max_prediction_order);
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if(avctx->prediction_order_method >= 0) {
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if(avctx->prediction_order_method > ORDER_METHOD_SEARCH) {
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av_log(avctx, AV_LOG_ERROR, "invalid prediction order method: %d\n",
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avctx->prediction_order_method);
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return -1;
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}
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s->options.prediction_order_method = avctx->prediction_order_method;
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}
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switch(avctx->prediction_order_method) {
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case ORDER_METHOD_EST: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
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"estimate"); break;
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case ORDER_METHOD_2LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
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"2-level"); break;
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case ORDER_METHOD_4LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
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"4-level"); break;
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case ORDER_METHOD_8LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
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"8-level"); break;
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case ORDER_METHOD_SEARCH: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
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"full search"); break;
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}
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if(avctx->min_partition_order >= 0) {
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if(avctx->min_partition_order > MAX_PARTITION_ORDER) {
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av_log(avctx, AV_LOG_ERROR, "invalid min partition order: %d\n",
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avctx->min_partition_order);
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return -1;
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}
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s->options.min_partition_order = avctx->min_partition_order;
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}
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if(avctx->max_partition_order >= 0) {
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if(avctx->max_partition_order > MAX_PARTITION_ORDER) {
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av_log(avctx, AV_LOG_ERROR, "invalid max partition order: %d\n",
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avctx->max_partition_order);
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return -1;
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}
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s->options.max_partition_order = avctx->max_partition_order;
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}
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if(s->options.max_partition_order < s->options.min_partition_order) {
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av_log(avctx, AV_LOG_ERROR, "invalid partition orders: min=%d max=%d\n",
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s->options.min_partition_order, s->options.max_partition_order);
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return -1;
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}
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av_log(avctx, AV_LOG_DEBUG, " partition order: %d, %d\n",
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s->options.min_partition_order, s->options.max_partition_order);
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if(avctx->frame_size > 0) {
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if(avctx->frame_size < FLAC_MIN_BLOCKSIZE ||
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avctx->frame_size > FLAC_MIN_BLOCKSIZE) {
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av_log(avctx, AV_LOG_ERROR, "invalid block size: %d\n",
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avctx->frame_size);
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return -1;
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}
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s->blocksize = avctx->frame_size;
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} else {
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s->blocksize = select_blocksize(s->samplerate, s->options.block_time_ms);
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avctx->frame_size = s->blocksize;
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}
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av_log(avctx, AV_LOG_DEBUG, " block size: %d\n", s->blocksize);
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/* set LPC precision */
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if(avctx->lpc_coeff_precision > 0) {
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if(avctx->lpc_coeff_precision > MAX_LPC_PRECISION) {
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av_log(avctx, AV_LOG_ERROR, "invalid lpc coeff precision: %d\n",
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avctx->lpc_coeff_precision);
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return -1;
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}
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s->options.lpc_coeff_precision = avctx->lpc_coeff_precision;
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} else {
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/* select LPC precision based on block size */
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if( s->blocksize <= 192) s->options.lpc_coeff_precision = 7;
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else if(s->blocksize <= 384) s->options.lpc_coeff_precision = 8;
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else if(s->blocksize <= 576) s->options.lpc_coeff_precision = 9;
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else if(s->blocksize <= 1152) s->options.lpc_coeff_precision = 10;
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else if(s->blocksize <= 2304) s->options.lpc_coeff_precision = 11;
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else if(s->blocksize <= 4608) s->options.lpc_coeff_precision = 12;
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else if(s->blocksize <= 8192) s->options.lpc_coeff_precision = 13;
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else if(s->blocksize <= 16384) s->options.lpc_coeff_precision = 14;
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else s->options.lpc_coeff_precision = 15;
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}
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av_log(avctx, AV_LOG_DEBUG, " lpc precision: %d\n",
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s->options.lpc_coeff_precision);
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/* set maximum encoded frame size in verbatim mode */
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if(s->channels == 2) {
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s->max_framesize = 14 + ((s->blocksize * 33 + 7) >> 3);
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} else {
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s->max_framesize = 14 + (s->blocksize * s->channels * 2);
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}
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streaminfo = av_malloc(FLAC_STREAMINFO_SIZE);
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write_streaminfo(s, streaminfo);
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avctx->extradata = streaminfo;
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avctx->extradata_size = FLAC_STREAMINFO_SIZE;
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s->frame_count = 0;
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avctx->coded_frame = avcodec_alloc_frame();
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avctx->coded_frame->key_frame = 1;
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return 0;
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}
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static void init_frame(FlacEncodeContext *s)
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{
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int i, ch;
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FlacFrame *frame;
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frame = &s->frame;
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for(i=0; i<16; i++) {
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if(s->blocksize == flac_blocksizes[i]) {
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frame->blocksize = flac_blocksizes[i];
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frame->bs_code[0] = i;
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frame->bs_code[1] = 0;
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break;
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}
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}
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if(i == 16) {
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frame->blocksize = s->blocksize;
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if(frame->blocksize <= 256) {
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frame->bs_code[0] = 6;
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frame->bs_code[1] = frame->blocksize-1;
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} else {
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frame->bs_code[0] = 7;
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frame->bs_code[1] = frame->blocksize-1;
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}
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}
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for(ch=0; ch<s->channels; ch++) {
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frame->subframes[ch].obits = 16;
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}
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}
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/**
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* Copy channel-interleaved input samples into separate subframes
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*/
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static void copy_samples(FlacEncodeContext *s, int16_t *samples)
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{
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int i, j, ch;
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FlacFrame *frame;
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frame = &s->frame;
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for(i=0,j=0; i<frame->blocksize; i++) {
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for(ch=0; ch<s->channels; ch++,j++) {
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frame->subframes[ch].samples[i] = samples[j];
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}
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}
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}
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#define rice_encode_count(sum, n, k) (((n)*((k)+1))+((sum-(n>>1))>>(k)))
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static int find_optimal_param(uint32_t sum, int n)
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{
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int k, k_opt;
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uint32_t nbits[MAX_RICE_PARAM+1];
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k_opt = 0;
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nbits[0] = UINT32_MAX;
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for(k=0; k<=MAX_RICE_PARAM; k++) {
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nbits[k] = rice_encode_count(sum, n, k);
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if(nbits[k] < nbits[k_opt]) {
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k_opt = k;
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}
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}
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return k_opt;
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}
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static uint32_t calc_optimal_rice_params(RiceContext *rc, int porder,
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uint32_t *sums, int n, int pred_order)
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{
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int i;
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int k, cnt, part;
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uint32_t all_bits;
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part = (1 << porder);
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all_bits = 0;
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cnt = (n >> porder) - pred_order;
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for(i=0; i<part; i++) {
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if(i == 1) cnt = (n >> porder);
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k = find_optimal_param(sums[i], cnt);
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rc->params[i] = k;
|
|
all_bits += rice_encode_count(sums[i], cnt, k);
|
|
}
|
|
all_bits += (4 * part);
|
|
|
|
rc->porder = porder;
|
|
|
|
return all_bits;
|
|
}
|
|
|
|
static void calc_sums(int pmin, int pmax, uint32_t *data, int n, int pred_order,
|
|
uint32_t sums[][MAX_PARTITIONS])
|
|
{
|
|
int i, j;
|
|
int parts;
|
|
uint32_t *res, *res_end;
|
|
|
|
/* sums for highest level */
|
|
parts = (1 << pmax);
|
|
res = &data[pred_order];
|
|
res_end = &data[n >> pmax];
|
|
for(i=0; i<parts; i++) {
|
|
sums[pmax][i] = 0;
|
|
while(res < res_end){
|
|
sums[pmax][i] += *(res++);
|
|
}
|
|
res_end+= n >> pmax;
|
|
}
|
|
/* sums for lower levels */
|
|
for(i=pmax-1; i>=pmin; i--) {
|
|
parts = (1 << i);
|
|
for(j=0; j<parts; j++) {
|
|
sums[i][j] = sums[i+1][2*j] + sums[i+1][2*j+1];
|
|
}
|
|
}
|
|
}
|
|
|
|
static uint32_t calc_rice_params(RiceContext *rc, int pmin, int pmax,
|
|
int32_t *data, int n, int pred_order)
|
|
{
|
|
int i;
|
|
uint32_t bits[MAX_PARTITION_ORDER+1];
|
|
int opt_porder;
|
|
RiceContext tmp_rc;
|
|
uint32_t *udata;
|
|
uint32_t sums[MAX_PARTITION_ORDER+1][MAX_PARTITIONS];
|
|
|
|
assert(pmin >= 0 && pmin <= MAX_PARTITION_ORDER);
|
|
assert(pmax >= 0 && pmax <= MAX_PARTITION_ORDER);
|
|
assert(pmin <= pmax);
|
|
|
|
udata = av_malloc(n * sizeof(uint32_t));
|
|
for(i=0; i<n; i++) {
|
|
udata[i] = (2*data[i]) ^ (data[i]>>31);
|
|
}
|
|
|
|
calc_sums(pmin, pmax, udata, n, pred_order, sums);
|
|
|
|
opt_porder = pmin;
|
|
bits[pmin] = UINT32_MAX;
|
|
for(i=pmin; i<=pmax; i++) {
|
|
bits[i] = calc_optimal_rice_params(&tmp_rc, i, sums[i], n, pred_order);
|
|
if(bits[i] <= bits[opt_porder]) {
|
|
opt_porder = i;
|
|
*rc= tmp_rc;
|
|
}
|
|
}
|
|
|
|
av_freep(&udata);
|
|
return bits[opt_porder];
|
|
}
|
|
|
|
static int get_max_p_order(int max_porder, int n, int order)
|
|
{
|
|
int porder = FFMIN(max_porder, av_log2(n^(n-1)));
|
|
if(order > 0)
|
|
porder = FFMIN(porder, av_log2(n/order));
|
|
return porder;
|
|
}
|
|
|
|
static uint32_t calc_rice_params_fixed(RiceContext *rc, int pmin, int pmax,
|
|
int32_t *data, int n, int pred_order,
|
|
int bps)
|
|
{
|
|
uint32_t bits;
|
|
pmin = get_max_p_order(pmin, n, pred_order);
|
|
pmax = get_max_p_order(pmax, n, pred_order);
|
|
bits = pred_order*bps + 6;
|
|
bits += calc_rice_params(rc, pmin, pmax, data, n, pred_order);
|
|
return bits;
|
|
}
|
|
|
|
static uint32_t calc_rice_params_lpc(RiceContext *rc, int pmin, int pmax,
|
|
int32_t *data, int n, int pred_order,
|
|
int bps, int precision)
|
|
{
|
|
uint32_t bits;
|
|
pmin = get_max_p_order(pmin, n, pred_order);
|
|
pmax = get_max_p_order(pmax, n, pred_order);
|
|
bits = pred_order*bps + 4 + 5 + pred_order*precision + 6;
|
|
bits += calc_rice_params(rc, pmin, pmax, data, n, pred_order);
|
|
return bits;
|
|
}
|
|
|
|
/**
|
|
* Apply Welch window function to audio block
|
|
*/
|
|
static void apply_welch_window(const int32_t *data, int len, double *w_data)
|
|
{
|
|
int i, n2;
|
|
double w;
|
|
double c;
|
|
|
|
n2 = (len >> 1);
|
|
c = 2.0 / (len - 1.0);
|
|
for(i=0; i<n2; i++) {
|
|
w = c - i - 1.0;
|
|
w = 1.0 - (w * w);
|
|
w_data[i] = data[i] * w;
|
|
w_data[len-1-i] = data[len-1-i] * w;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Calculates autocorrelation data from audio samples
|
|
* A Welch window function is applied before calculation.
|
|
*/
|
|
static void compute_autocorr(const int32_t *data, int len, int lag,
|
|
double *autoc)
|
|
{
|
|
int i, lag_ptr;
|
|
double tmp[len + lag];
|
|
double *data1= tmp + lag;
|
|
|
|
apply_welch_window(data, len, data1);
|
|
|
|
for(i=0; i<lag; i++){
|
|
autoc[i] = 1.0;
|
|
data1[i-lag]= 0.0;
|
|
}
|
|
|
|
for(i=0; i<len; i++){
|
|
for(lag_ptr= i-lag; lag_ptr<=i; lag_ptr++){
|
|
autoc[i-lag_ptr] += data1[i] * data1[lag_ptr];
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Levinson-Durbin recursion.
|
|
* Produces LPC coefficients from autocorrelation data.
|
|
*/
|
|
static void compute_lpc_coefs(const double *autoc, int max_order,
|
|
double lpc[][MAX_LPC_ORDER], double *ref)
|
|
{
|
|
int i, j, i2;
|
|
double r, err, tmp;
|
|
double lpc_tmp[MAX_LPC_ORDER];
|
|
|
|
for(i=0; i<max_order; i++) lpc_tmp[i] = 0;
|
|
err = autoc[0];
|
|
|
|
for(i=0; i<max_order; i++) {
|
|
r = -autoc[i+1];
|
|
for(j=0; j<i; j++) {
|
|
r -= lpc_tmp[j] * autoc[i-j];
|
|
}
|
|
r /= err;
|
|
ref[i] = fabs(r);
|
|
|
|
err *= 1.0 - (r * r);
|
|
|
|
i2 = (i >> 1);
|
|
lpc_tmp[i] = r;
|
|
for(j=0; j<i2; j++) {
|
|
tmp = lpc_tmp[j];
|
|
lpc_tmp[j] += r * lpc_tmp[i-1-j];
|
|
lpc_tmp[i-1-j] += r * tmp;
|
|
}
|
|
if(i & 1) {
|
|
lpc_tmp[j] += lpc_tmp[j] * r;
|
|
}
|
|
|
|
for(j=0; j<=i; j++) {
|
|
lpc[i][j] = -lpc_tmp[j];
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Quantize LPC coefficients
|
|
*/
|
|
static void quantize_lpc_coefs(double *lpc_in, int order, int precision,
|
|
int32_t *lpc_out, int *shift)
|
|
{
|
|
int i;
|
|
double cmax;
|
|
int32_t qmax;
|
|
int sh;
|
|
|
|
/* define maximum levels */
|
|
qmax = (1 << (precision - 1)) - 1;
|
|
|
|
/* find maximum coefficient value */
|
|
cmax = 0.0;
|
|
for(i=0; i<order; i++) {
|
|
cmax= FFMAX(cmax, fabs(lpc_in[i]));
|
|
}
|
|
|
|
/* if maximum value quantizes to zero, return all zeros */
|
|
if(cmax * (1 << MAX_LPC_SHIFT) < 1.0) {
|
|
*shift = 0;
|
|
memset(lpc_out, 0, sizeof(int32_t) * order);
|
|
return;
|
|
}
|
|
|
|
/* calculate level shift which scales max coeff to available bits */
|
|
sh = MAX_LPC_SHIFT;
|
|
while((cmax * (1 << sh) > qmax) && (sh > 0)) {
|
|
sh--;
|
|
}
|
|
|
|
/* since negative shift values are unsupported in decoder, scale down
|
|
coefficients instead */
|
|
if(sh == 0 && cmax > qmax) {
|
|
double scale = ((double)qmax) / cmax;
|
|
for(i=0; i<order; i++) {
|
|
lpc_in[i] *= scale;
|
|
}
|
|
}
|
|
|
|
/* output quantized coefficients and level shift */
|
|
for(i=0; i<order; i++) {
|
|
lpc_out[i] = (int32_t)(lpc_in[i] * (1 << sh));
|
|
}
|
|
*shift = sh;
|
|
}
|
|
|
|
static int estimate_best_order(double *ref, int max_order)
|
|
{
|
|
int i, est;
|
|
|
|
est = 1;
|
|
for(i=max_order-1; i>=0; i--) {
|
|
if(ref[i] > 0.10) {
|
|
est = i+1;
|
|
break;
|
|
}
|
|
}
|
|
return est;
|
|
}
|
|
|
|
/**
|
|
* Calculate LPC coefficients for multiple orders
|
|
*/
|
|
static int lpc_calc_coefs(const int32_t *samples, int blocksize, int max_order,
|
|
int precision, int32_t coefs[][MAX_LPC_ORDER],
|
|
int *shift)
|
|
{
|
|
double autoc[MAX_LPC_ORDER+1];
|
|
double ref[MAX_LPC_ORDER];
|
|
double lpc[MAX_LPC_ORDER][MAX_LPC_ORDER];
|
|
int i;
|
|
int opt_order;
|
|
|
|
assert(max_order >= MIN_LPC_ORDER && max_order <= MAX_LPC_ORDER);
|
|
|
|
compute_autocorr(samples, blocksize, max_order+1, autoc);
|
|
|
|
compute_lpc_coefs(autoc, max_order, lpc, ref);
|
|
|
|
opt_order = estimate_best_order(ref, max_order);
|
|
|
|
i = opt_order-1;
|
|
quantize_lpc_coefs(lpc[i], i+1, precision, coefs[i], &shift[i]);
|
|
|
|
return opt_order;
|
|
}
|
|
|
|
|
|
static void encode_residual_verbatim(int32_t *res, int32_t *smp, int n)
|
|
{
|
|
assert(n > 0);
|
|
memcpy(res, smp, n * sizeof(int32_t));
|
|
}
|
|
|
|
static void encode_residual_fixed(int32_t *res, const int32_t *smp, int n,
|
|
int order)
|
|
{
|
|
int i;
|
|
|
|
for(i=0; i<order; i++) {
|
|
res[i] = smp[i];
|
|
}
|
|
|
|
if(order==0){
|
|
for(i=order; i<n; i++)
|
|
res[i]= smp[i];
|
|
}else if(order==1){
|
|
for(i=order; i<n; i++)
|
|
res[i]= smp[i] - smp[i-1];
|
|
}else if(order==2){
|
|
for(i=order; i<n; i++)
|
|
res[i]= smp[i] - 2*smp[i-1] + smp[i-2];
|
|
}else if(order==3){
|
|
for(i=order; i<n; i++)
|
|
res[i]= smp[i] - 3*smp[i-1] + 3*smp[i-2] - smp[i-3];
|
|
}else{
|
|
for(i=order; i<n; i++)
|
|
res[i]= smp[i] - 4*smp[i-1] + 6*smp[i-2] - 4*smp[i-3] + smp[i-4];
|
|
}
|
|
}
|
|
|
|
static void encode_residual_lpc(int32_t *res, const int32_t *smp, int n,
|
|
int order, const int32_t *coefs, int shift)
|
|
{
|
|
int i, j;
|
|
int32_t pred;
|
|
|
|
for(i=0; i<order; i++) {
|
|
res[i] = smp[i];
|
|
}
|
|
for(i=order; i<n; i++) {
|
|
pred = 0;
|
|
for(j=0; j<order; j++) {
|
|
pred += coefs[j] * smp[i-j-1];
|
|
}
|
|
res[i] = smp[i] - (pred >> shift);
|
|
}
|
|
}
|
|
|
|
static int encode_residual(FlacEncodeContext *ctx, int ch)
|
|
{
|
|
int i, n;
|
|
int min_order, max_order, opt_order, precision;
|
|
int min_porder, max_porder;
|
|
FlacFrame *frame;
|
|
FlacSubframe *sub;
|
|
int32_t coefs[MAX_LPC_ORDER][MAX_LPC_ORDER];
|
|
int shift[MAX_LPC_ORDER];
|
|
int32_t *res, *smp;
|
|
|
|
frame = &ctx->frame;
|
|
sub = &frame->subframes[ch];
|
|
res = sub->residual;
|
|
smp = sub->samples;
|
|
n = frame->blocksize;
|
|
|
|
/* CONSTANT */
|
|
for(i=1; i<n; i++) {
|
|
if(smp[i] != smp[0]) break;
|
|
}
|
|
if(i == n) {
|
|
sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
|
|
res[0] = smp[0];
|
|
return sub->obits;
|
|
}
|
|
|
|
/* VERBATIM */
|
|
if(n < 5) {
|
|
sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
|
|
encode_residual_verbatim(res, smp, n);
|
|
return sub->obits * n;
|
|
}
|
|
|
|
min_order = ctx->options.min_prediction_order;
|
|
max_order = ctx->options.max_prediction_order;
|
|
min_porder = ctx->options.min_partition_order;
|
|
max_porder = ctx->options.max_partition_order;
|
|
precision = ctx->options.lpc_coeff_precision;
|
|
|
|
/* FIXED */
|
|
if(!ctx->options.use_lpc || max_order == 0 || (n <= max_order)) {
|
|
uint32_t bits[MAX_FIXED_ORDER+1];
|
|
if(max_order > MAX_FIXED_ORDER) max_order = MAX_FIXED_ORDER;
|
|
opt_order = 0;
|
|
bits[0] = UINT32_MAX;
|
|
for(i=min_order; i<=max_order; i++) {
|
|
encode_residual_fixed(res, smp, n, i);
|
|
bits[i] = calc_rice_params_fixed(&sub->rc, min_porder, max_porder, res,
|
|
n, i, sub->obits);
|
|
if(bits[i] < bits[opt_order]) {
|
|
opt_order = i;
|
|
}
|
|
}
|
|
sub->order = opt_order;
|
|
sub->type = FLAC_SUBFRAME_FIXED;
|
|
sub->type_code = sub->type | sub->order;
|
|
if(sub->order != max_order) {
|
|
encode_residual_fixed(res, smp, n, sub->order);
|
|
return calc_rice_params_fixed(&sub->rc, min_porder, max_porder, res, n,
|
|
sub->order, sub->obits);
|
|
}
|
|
return bits[sub->order];
|
|
}
|
|
|
|
/* LPC */
|
|
sub->order = lpc_calc_coefs(smp, n, max_order, precision, coefs, shift);
|
|
sub->type = FLAC_SUBFRAME_LPC;
|
|
sub->type_code = sub->type | (sub->order-1);
|
|
sub->shift = shift[sub->order-1];
|
|
for(i=0; i<sub->order; i++) {
|
|
sub->coefs[i] = coefs[sub->order-1][i];
|
|
}
|
|
encode_residual_lpc(res, smp, n, sub->order, sub->coefs, sub->shift);
|
|
return calc_rice_params_lpc(&sub->rc, min_porder, max_porder, res, n, sub->order,
|
|
sub->obits, precision);
|
|
}
|
|
|
|
static int encode_residual_v(FlacEncodeContext *ctx, int ch)
|
|
{
|
|
int i, n;
|
|
FlacFrame *frame;
|
|
FlacSubframe *sub;
|
|
int32_t *res, *smp;
|
|
|
|
frame = &ctx->frame;
|
|
sub = &frame->subframes[ch];
|
|
res = sub->residual;
|
|
smp = sub->samples;
|
|
n = frame->blocksize;
|
|
|
|
/* CONSTANT */
|
|
for(i=1; i<n; i++) {
|
|
if(smp[i] != smp[0]) break;
|
|
}
|
|
if(i == n) {
|
|
sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
|
|
res[0] = smp[0];
|
|
return sub->obits;
|
|
}
|
|
|
|
/* VERBATIM */
|
|
sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
|
|
encode_residual_verbatim(res, smp, n);
|
|
return sub->obits * n;
|
|
}
|
|
|
|
static int estimate_stereo_mode(int32_t *left_ch, int32_t *right_ch, int n)
|
|
{
|
|
int i, best;
|
|
int32_t lt, rt;
|
|
uint64_t sum[4];
|
|
uint64_t score[4];
|
|
int k;
|
|
|
|
/* calculate sum of 2nd order residual for each channel */
|
|
sum[0] = sum[1] = sum[2] = sum[3] = 0;
|
|
for(i=2; i<n; i++) {
|
|
lt = left_ch[i] - 2*left_ch[i-1] + left_ch[i-2];
|
|
rt = right_ch[i] - 2*right_ch[i-1] + right_ch[i-2];
|
|
sum[2] += ABS((lt + rt) >> 1);
|
|
sum[3] += ABS(lt - rt);
|
|
sum[0] += ABS(lt);
|
|
sum[1] += ABS(rt);
|
|
}
|
|
/* estimate bit counts */
|
|
for(i=0; i<4; i++) {
|
|
k = find_optimal_param(2*sum[i], n);
|
|
sum[i] = rice_encode_count(2*sum[i], n, k);
|
|
}
|
|
|
|
/* calculate score for each mode */
|
|
score[0] = sum[0] + sum[1];
|
|
score[1] = sum[0] + sum[3];
|
|
score[2] = sum[1] + sum[3];
|
|
score[3] = sum[2] + sum[3];
|
|
|
|
/* return mode with lowest score */
|
|
best = 0;
|
|
for(i=1; i<4; i++) {
|
|
if(score[i] < score[best]) {
|
|
best = i;
|
|
}
|
|
}
|
|
if(best == 0) {
|
|
return FLAC_CHMODE_LEFT_RIGHT;
|
|
} else if(best == 1) {
|
|
return FLAC_CHMODE_LEFT_SIDE;
|
|
} else if(best == 2) {
|
|
return FLAC_CHMODE_RIGHT_SIDE;
|
|
} else {
|
|
return FLAC_CHMODE_MID_SIDE;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Perform stereo channel decorrelation
|
|
*/
|
|
static void channel_decorrelation(FlacEncodeContext *ctx)
|
|
{
|
|
FlacFrame *frame;
|
|
int32_t *left, *right;
|
|
int i, n;
|
|
|
|
frame = &ctx->frame;
|
|
n = frame->blocksize;
|
|
left = frame->subframes[0].samples;
|
|
right = frame->subframes[1].samples;
|
|
|
|
if(ctx->channels != 2) {
|
|
frame->ch_mode = FLAC_CHMODE_NOT_STEREO;
|
|
return;
|
|
}
|
|
|
|
frame->ch_mode = estimate_stereo_mode(left, right, n);
|
|
|
|
/* perform decorrelation and adjust bits-per-sample */
|
|
if(frame->ch_mode == FLAC_CHMODE_LEFT_RIGHT) {
|
|
return;
|
|
}
|
|
if(frame->ch_mode == FLAC_CHMODE_MID_SIDE) {
|
|
int32_t tmp;
|
|
for(i=0; i<n; i++) {
|
|
tmp = left[i];
|
|
left[i] = (tmp + right[i]) >> 1;
|
|
right[i] = tmp - right[i];
|
|
}
|
|
frame->subframes[1].obits++;
|
|
} else if(frame->ch_mode == FLAC_CHMODE_LEFT_SIDE) {
|
|
for(i=0; i<n; i++) {
|
|
right[i] = left[i] - right[i];
|
|
}
|
|
frame->subframes[1].obits++;
|
|
} else {
|
|
for(i=0; i<n; i++) {
|
|
left[i] -= right[i];
|
|
}
|
|
frame->subframes[0].obits++;
|
|
}
|
|
}
|
|
|
|
static void put_sbits(PutBitContext *pb, int bits, int32_t val)
|
|
{
|
|
assert(bits >= 0 && bits <= 31);
|
|
|
|
put_bits(pb, bits, val & ((1<<bits)-1));
|
|
}
|
|
|
|
static void write_utf8(PutBitContext *pb, uint32_t val)
|
|
{
|
|
int bytes, shift;
|
|
|
|
if(val < 0x80){
|
|
put_bits(pb, 8, val);
|
|
return;
|
|
}
|
|
|
|
bytes= (av_log2(val)+4) / 5;
|
|
shift = (bytes - 1) * 6;
|
|
put_bits(pb, 8, (256 - (256>>bytes)) | (val >> shift));
|
|
while(shift >= 6){
|
|
shift -= 6;
|
|
put_bits(pb, 8, 0x80 | ((val >> shift) & 0x3F));
|
|
}
|
|
}
|
|
|
|
static void output_frame_header(FlacEncodeContext *s)
|
|
{
|
|
FlacFrame *frame;
|
|
int crc;
|
|
|
|
frame = &s->frame;
|
|
|
|
put_bits(&s->pb, 16, 0xFFF8);
|
|
put_bits(&s->pb, 4, frame->bs_code[0]);
|
|
put_bits(&s->pb, 4, s->sr_code[0]);
|
|
if(frame->ch_mode == FLAC_CHMODE_NOT_STEREO) {
|
|
put_bits(&s->pb, 4, s->ch_code);
|
|
} else {
|
|
put_bits(&s->pb, 4, frame->ch_mode);
|
|
}
|
|
put_bits(&s->pb, 3, 4); /* bits-per-sample code */
|
|
put_bits(&s->pb, 1, 0);
|
|
write_utf8(&s->pb, s->frame_count);
|
|
if(frame->bs_code[0] == 6) {
|
|
put_bits(&s->pb, 8, frame->bs_code[1]);
|
|
} else if(frame->bs_code[0] == 7) {
|
|
put_bits(&s->pb, 16, frame->bs_code[1]);
|
|
}
|
|
if(s->sr_code[0] == 12) {
|
|
put_bits(&s->pb, 8, s->sr_code[1]);
|
|
} else if(s->sr_code[0] > 12) {
|
|
put_bits(&s->pb, 16, s->sr_code[1]);
|
|
}
|
|
flush_put_bits(&s->pb);
|
|
crc = av_crc(av_crc07, 0, s->pb.buf, put_bits_count(&s->pb)>>3);
|
|
put_bits(&s->pb, 8, crc);
|
|
}
|
|
|
|
static void output_subframe_constant(FlacEncodeContext *s, int ch)
|
|
{
|
|
FlacSubframe *sub;
|
|
int32_t res;
|
|
|
|
sub = &s->frame.subframes[ch];
|
|
res = sub->residual[0];
|
|
put_sbits(&s->pb, sub->obits, res);
|
|
}
|
|
|
|
static void output_subframe_verbatim(FlacEncodeContext *s, int ch)
|
|
{
|
|
int i;
|
|
FlacFrame *frame;
|
|
FlacSubframe *sub;
|
|
int32_t res;
|
|
|
|
frame = &s->frame;
|
|
sub = &frame->subframes[ch];
|
|
|
|
for(i=0; i<frame->blocksize; i++) {
|
|
res = sub->residual[i];
|
|
put_sbits(&s->pb, sub->obits, res);
|
|
}
|
|
}
|
|
|
|
static void output_residual(FlacEncodeContext *ctx, int ch)
|
|
{
|
|
int i, j, p, n, parts;
|
|
int k, porder, psize, res_cnt;
|
|
FlacFrame *frame;
|
|
FlacSubframe *sub;
|
|
int32_t *res;
|
|
|
|
frame = &ctx->frame;
|
|
sub = &frame->subframes[ch];
|
|
res = sub->residual;
|
|
n = frame->blocksize;
|
|
|
|
/* rice-encoded block */
|
|
put_bits(&ctx->pb, 2, 0);
|
|
|
|
/* partition order */
|
|
porder = sub->rc.porder;
|
|
psize = n >> porder;
|
|
parts = (1 << porder);
|
|
put_bits(&ctx->pb, 4, porder);
|
|
res_cnt = psize - sub->order;
|
|
|
|
/* residual */
|
|
j = sub->order;
|
|
for(p=0; p<parts; p++) {
|
|
k = sub->rc.params[p];
|
|
put_bits(&ctx->pb, 4, k);
|
|
if(p == 1) res_cnt = psize;
|
|
for(i=0; i<res_cnt && j<n; i++, j++) {
|
|
set_sr_golomb_flac(&ctx->pb, res[j], k, INT32_MAX, 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void output_subframe_fixed(FlacEncodeContext *ctx, int ch)
|
|
{
|
|
int i;
|
|
FlacFrame *frame;
|
|
FlacSubframe *sub;
|
|
|
|
frame = &ctx->frame;
|
|
sub = &frame->subframes[ch];
|
|
|
|
/* warm-up samples */
|
|
for(i=0; i<sub->order; i++) {
|
|
put_sbits(&ctx->pb, sub->obits, sub->residual[i]);
|
|
}
|
|
|
|
/* residual */
|
|
output_residual(ctx, ch);
|
|
}
|
|
|
|
static void output_subframe_lpc(FlacEncodeContext *ctx, int ch)
|
|
{
|
|
int i, cbits;
|
|
FlacFrame *frame;
|
|
FlacSubframe *sub;
|
|
|
|
frame = &ctx->frame;
|
|
sub = &frame->subframes[ch];
|
|
|
|
/* warm-up samples */
|
|
for(i=0; i<sub->order; i++) {
|
|
put_sbits(&ctx->pb, sub->obits, sub->residual[i]);
|
|
}
|
|
|
|
/* LPC coefficients */
|
|
cbits = ctx->options.lpc_coeff_precision;
|
|
put_bits(&ctx->pb, 4, cbits-1);
|
|
put_sbits(&ctx->pb, 5, sub->shift);
|
|
for(i=0; i<sub->order; i++) {
|
|
put_sbits(&ctx->pb, cbits, sub->coefs[i]);
|
|
}
|
|
|
|
/* residual */
|
|
output_residual(ctx, ch);
|
|
}
|
|
|
|
static void output_subframes(FlacEncodeContext *s)
|
|
{
|
|
FlacFrame *frame;
|
|
FlacSubframe *sub;
|
|
int ch;
|
|
|
|
frame = &s->frame;
|
|
|
|
for(ch=0; ch<s->channels; ch++) {
|
|
sub = &frame->subframes[ch];
|
|
|
|
/* subframe header */
|
|
put_bits(&s->pb, 1, 0);
|
|
put_bits(&s->pb, 6, sub->type_code);
|
|
put_bits(&s->pb, 1, 0); /* no wasted bits */
|
|
|
|
/* subframe */
|
|
if(sub->type == FLAC_SUBFRAME_CONSTANT) {
|
|
output_subframe_constant(s, ch);
|
|
} else if(sub->type == FLAC_SUBFRAME_VERBATIM) {
|
|
output_subframe_verbatim(s, ch);
|
|
} else if(sub->type == FLAC_SUBFRAME_FIXED) {
|
|
output_subframe_fixed(s, ch);
|
|
} else if(sub->type == FLAC_SUBFRAME_LPC) {
|
|
output_subframe_lpc(s, ch);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void output_frame_footer(FlacEncodeContext *s)
|
|
{
|
|
int crc;
|
|
flush_put_bits(&s->pb);
|
|
crc = bswap_16(av_crc(av_crc8005, 0, s->pb.buf, put_bits_count(&s->pb)>>3));
|
|
put_bits(&s->pb, 16, crc);
|
|
flush_put_bits(&s->pb);
|
|
}
|
|
|
|
static int flac_encode_frame(AVCodecContext *avctx, uint8_t *frame,
|
|
int buf_size, void *data)
|
|
{
|
|
int ch;
|
|
FlacEncodeContext *s;
|
|
int16_t *samples = data;
|
|
int out_bytes;
|
|
|
|
s = avctx->priv_data;
|
|
|
|
s->blocksize = avctx->frame_size;
|
|
init_frame(s);
|
|
|
|
copy_samples(s, samples);
|
|
|
|
channel_decorrelation(s);
|
|
|
|
for(ch=0; ch<s->channels; ch++) {
|
|
encode_residual(s, ch);
|
|
}
|
|
init_put_bits(&s->pb, frame, buf_size);
|
|
output_frame_header(s);
|
|
output_subframes(s);
|
|
output_frame_footer(s);
|
|
out_bytes = put_bits_count(&s->pb) >> 3;
|
|
|
|
if(out_bytes > s->max_framesize || out_bytes >= buf_size) {
|
|
/* frame too large. use verbatim mode */
|
|
for(ch=0; ch<s->channels; ch++) {
|
|
encode_residual_v(s, ch);
|
|
}
|
|
init_put_bits(&s->pb, frame, buf_size);
|
|
output_frame_header(s);
|
|
output_subframes(s);
|
|
output_frame_footer(s);
|
|
out_bytes = put_bits_count(&s->pb) >> 3;
|
|
|
|
if(out_bytes > s->max_framesize || out_bytes >= buf_size) {
|
|
/* still too large. must be an error. */
|
|
av_log(avctx, AV_LOG_ERROR, "error encoding frame\n");
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
s->frame_count++;
|
|
return out_bytes;
|
|
}
|
|
|
|
static int flac_encode_close(AVCodecContext *avctx)
|
|
{
|
|
av_freep(&avctx->extradata);
|
|
avctx->extradata_size = 0;
|
|
av_freep(&avctx->coded_frame);
|
|
return 0;
|
|
}
|
|
|
|
AVCodec flac_encoder = {
|
|
"flac",
|
|
CODEC_TYPE_AUDIO,
|
|
CODEC_ID_FLAC,
|
|
sizeof(FlacEncodeContext),
|
|
flac_encode_init,
|
|
flac_encode_frame,
|
|
flac_encode_close,
|
|
NULL,
|
|
.capabilities = CODEC_CAP_SMALL_LAST_FRAME,
|
|
};
|