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FFmpeg/libavcodec/flacenc.c
Justin Ruggles fde82ca7e4 Move autocorrelation function from flacenc.c to lpc.c. Also rename the 
corresponding dsputil functions and remove their dependency on the FLAC
encoder.
Fixes Issue1486.

Originally committed as revision 20266 to svn://svn.ffmpeg.org/ffmpeg/trunk
2009-10-17 21:00:39 +00:00

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/**
* FLAC audio encoder
* Copyright (c) 2006 Justin Ruggles <justin.ruggles@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/crc.h"
#include "libavutil/md5.h"
#include "avcodec.h"
#include "get_bits.h"
#include "dsputil.h"
#include "golomb.h"
#include "lpc.h"
#include "flac.h"
#include "flacdata.h"
#define FLAC_SUBFRAME_CONSTANT 0
#define FLAC_SUBFRAME_VERBATIM 1
#define FLAC_SUBFRAME_FIXED 8
#define FLAC_SUBFRAME_LPC 32
#define MAX_FIXED_ORDER 4
#define MAX_PARTITION_ORDER 8
#define MAX_PARTITIONS (1 << MAX_PARTITION_ORDER)
#define MAX_LPC_PRECISION 15
#define MAX_LPC_SHIFT 15
#define MAX_RICE_PARAM 14
typedef struct CompressionOptions {
int compression_level;
int block_time_ms;
int use_lpc;
int lpc_coeff_precision;
int min_prediction_order;
int max_prediction_order;
int prediction_order_method;
int min_partition_order;
int max_partition_order;
} CompressionOptions;
typedef struct RiceContext {
int porder;
int params[MAX_PARTITIONS];
} RiceContext;
typedef struct FlacSubframe {
int type;
int type_code;
int obits;
int order;
int32_t coefs[MAX_LPC_ORDER];
int shift;
RiceContext rc;
int32_t samples[FLAC_MAX_BLOCKSIZE];
int32_t residual[FLAC_MAX_BLOCKSIZE+1];
} FlacSubframe;
typedef struct FlacFrame {
FlacSubframe subframes[FLAC_MAX_CHANNELS];
int blocksize;
int bs_code[2];
uint8_t crc8;
int ch_mode;
} FlacFrame;
typedef struct FlacEncodeContext {
PutBitContext pb;
int channels;
int samplerate;
int sr_code[2];
int max_blocksize;
int min_framesize;
int max_framesize;
int max_encoded_framesize;
uint32_t frame_count;
uint64_t sample_count;
uint8_t md5sum[16];
FlacFrame frame;
CompressionOptions options;
AVCodecContext *avctx;
DSPContext dsp;
struct AVMD5 *md5ctx;
} FlacEncodeContext;
/**
* Writes streaminfo metadata block to byte array
*/
static void write_streaminfo(FlacEncodeContext *s, uint8_t *header)
{
PutBitContext pb;
memset(header, 0, FLAC_STREAMINFO_SIZE);
init_put_bits(&pb, header, FLAC_STREAMINFO_SIZE);
/* streaminfo metadata block */
put_bits(&pb, 16, s->max_blocksize);
put_bits(&pb, 16, s->max_blocksize);
put_bits(&pb, 24, s->min_framesize);
put_bits(&pb, 24, s->max_framesize);
put_bits(&pb, 20, s->samplerate);
put_bits(&pb, 3, s->channels-1);
put_bits(&pb, 5, 15); /* bits per sample - 1 */
/* write 36-bit sample count in 2 put_bits() calls */
put_bits(&pb, 24, (s->sample_count & 0xFFFFFF000LL) >> 12);
put_bits(&pb, 12, s->sample_count & 0x000000FFFLL);
flush_put_bits(&pb);
memcpy(&header[18], s->md5sum, 16);
}
/**
* Sets blocksize based on samplerate
* Chooses the closest predefined blocksize >= BLOCK_TIME_MS milliseconds
*/
static int select_blocksize(int samplerate, int block_time_ms)
{
int i;
int target;
int blocksize;
assert(samplerate > 0);
blocksize = ff_flac_blocksize_table[1];
target = (samplerate * block_time_ms) / 1000;
for(i=0; i<16; i++) {
if(target >= ff_flac_blocksize_table[i] && ff_flac_blocksize_table[i] > blocksize) {
blocksize = ff_flac_blocksize_table[i];
}
}
return blocksize;
}
static av_cold int flac_encode_init(AVCodecContext *avctx)
{
int freq = avctx->sample_rate;
int channels = avctx->channels;
FlacEncodeContext *s = avctx->priv_data;
int i, level;
uint8_t *streaminfo;
s->avctx = avctx;
dsputil_init(&s->dsp, avctx);
if(avctx->sample_fmt != SAMPLE_FMT_S16) {
return -1;
}
if(channels < 1 || channels > FLAC_MAX_CHANNELS) {
return -1;
}
s->channels = channels;
/* find samplerate in table */
if(freq < 1)
return -1;
for(i=4; i<12; i++) {
if(freq == ff_flac_sample_rate_table[i]) {
s->samplerate = ff_flac_sample_rate_table[i];
s->sr_code[0] = i;
s->sr_code[1] = 0;
break;
}
}
/* if not in table, samplerate is non-standard */
if(i == 12) {
if(freq % 1000 == 0 && freq < 255000) {
s->sr_code[0] = 12;
s->sr_code[1] = freq / 1000;
} else if(freq % 10 == 0 && freq < 655350) {
s->sr_code[0] = 14;
s->sr_code[1] = freq / 10;
} else if(freq < 65535) {
s->sr_code[0] = 13;
s->sr_code[1] = freq;
} else {
return -1;
}
s->samplerate = freq;
}
/* set compression option defaults based on avctx->compression_level */
if(avctx->compression_level < 0) {
s->options.compression_level = 5;
} else {
s->options.compression_level = avctx->compression_level;
}
av_log(avctx, AV_LOG_DEBUG, " compression: %d\n", s->options.compression_level);
level= s->options.compression_level;
if(level > 12) {
av_log(avctx, AV_LOG_ERROR, "invalid compression level: %d\n",
s->options.compression_level);
return -1;
}
s->options.block_time_ms = ((int[]){ 27, 27, 27,105,105,105,105,105,105,105,105,105,105})[level];
s->options.use_lpc = ((int[]){ 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1})[level];
s->options.min_prediction_order= ((int[]){ 2, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1})[level];
s->options.max_prediction_order= ((int[]){ 3, 4, 4, 6, 8, 8, 8, 8, 12, 12, 12, 32, 32})[level];
s->options.prediction_order_method = ((int[]){ ORDER_METHOD_EST, ORDER_METHOD_EST, ORDER_METHOD_EST,
ORDER_METHOD_EST, ORDER_METHOD_EST, ORDER_METHOD_EST,
ORDER_METHOD_4LEVEL, ORDER_METHOD_LOG, ORDER_METHOD_4LEVEL,
ORDER_METHOD_LOG, ORDER_METHOD_SEARCH, ORDER_METHOD_LOG,
ORDER_METHOD_SEARCH})[level];
s->options.min_partition_order = ((int[]){ 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0})[level];
s->options.max_partition_order = ((int[]){ 2, 2, 3, 3, 3, 8, 8, 8, 8, 8, 8, 8, 8})[level];
/* set compression option overrides from AVCodecContext */
if(avctx->use_lpc >= 0) {
s->options.use_lpc = av_clip(avctx->use_lpc, 0, 11);
}
if(s->options.use_lpc == 1)
av_log(avctx, AV_LOG_DEBUG, " use lpc: Levinson-Durbin recursion with Welch window\n");
else if(s->options.use_lpc > 1)
av_log(avctx, AV_LOG_DEBUG, " use lpc: Cholesky factorization\n");
if(avctx->min_prediction_order >= 0) {
if(s->options.use_lpc) {
if(avctx->min_prediction_order < MIN_LPC_ORDER ||
avctx->min_prediction_order > MAX_LPC_ORDER) {
av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
avctx->min_prediction_order);
return -1;
}
} else {
if(avctx->min_prediction_order > MAX_FIXED_ORDER) {
av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
avctx->min_prediction_order);
return -1;
}
}
s->options.min_prediction_order = avctx->min_prediction_order;
}
if(avctx->max_prediction_order >= 0) {
if(s->options.use_lpc) {
if(avctx->max_prediction_order < MIN_LPC_ORDER ||
avctx->max_prediction_order > MAX_LPC_ORDER) {
av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
avctx->max_prediction_order);
return -1;
}
} else {
if(avctx->max_prediction_order > MAX_FIXED_ORDER) {
av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
avctx->max_prediction_order);
return -1;
}
}
s->options.max_prediction_order = avctx->max_prediction_order;
}
if(s->options.max_prediction_order < s->options.min_prediction_order) {
av_log(avctx, AV_LOG_ERROR, "invalid prediction orders: min=%d max=%d\n",
s->options.min_prediction_order, s->options.max_prediction_order);
return -1;
}
av_log(avctx, AV_LOG_DEBUG, " prediction order: %d, %d\n",
s->options.min_prediction_order, s->options.max_prediction_order);
if(avctx->prediction_order_method >= 0) {
if(avctx->prediction_order_method > ORDER_METHOD_LOG) {
av_log(avctx, AV_LOG_ERROR, "invalid prediction order method: %d\n",
avctx->prediction_order_method);
return -1;
}
s->options.prediction_order_method = avctx->prediction_order_method;
}
switch(s->options.prediction_order_method) {
case ORDER_METHOD_EST: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
"estimate"); break;
case ORDER_METHOD_2LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
"2-level"); break;
case ORDER_METHOD_4LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
"4-level"); break;
case ORDER_METHOD_8LEVEL: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
"8-level"); break;
case ORDER_METHOD_SEARCH: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
"full search"); break;
case ORDER_METHOD_LOG: av_log(avctx, AV_LOG_DEBUG, " order method: %s\n",
"log search"); break;
}
if(avctx->min_partition_order >= 0) {
if(avctx->min_partition_order > MAX_PARTITION_ORDER) {
av_log(avctx, AV_LOG_ERROR, "invalid min partition order: %d\n",
avctx->min_partition_order);
return -1;
}
s->options.min_partition_order = avctx->min_partition_order;
}
if(avctx->max_partition_order >= 0) {
if(avctx->max_partition_order > MAX_PARTITION_ORDER) {
av_log(avctx, AV_LOG_ERROR, "invalid max partition order: %d\n",
avctx->max_partition_order);
return -1;
}
s->options.max_partition_order = avctx->max_partition_order;
}
if(s->options.max_partition_order < s->options.min_partition_order) {
av_log(avctx, AV_LOG_ERROR, "invalid partition orders: min=%d max=%d\n",
s->options.min_partition_order, s->options.max_partition_order);
return -1;
}
av_log(avctx, AV_LOG_DEBUG, " partition order: %d, %d\n",
s->options.min_partition_order, s->options.max_partition_order);
if(avctx->frame_size > 0) {
if(avctx->frame_size < FLAC_MIN_BLOCKSIZE ||
avctx->frame_size > FLAC_MAX_BLOCKSIZE) {
av_log(avctx, AV_LOG_ERROR, "invalid block size: %d\n",
avctx->frame_size);
return -1;
}
} else {
s->avctx->frame_size = select_blocksize(s->samplerate, s->options.block_time_ms);
}
s->max_blocksize = s->avctx->frame_size;
av_log(avctx, AV_LOG_DEBUG, " block size: %d\n", s->avctx->frame_size);
/* set LPC precision */
if(avctx->lpc_coeff_precision > 0) {
if(avctx->lpc_coeff_precision > MAX_LPC_PRECISION) {
av_log(avctx, AV_LOG_ERROR, "invalid lpc coeff precision: %d\n",
avctx->lpc_coeff_precision);
return -1;
}
s->options.lpc_coeff_precision = avctx->lpc_coeff_precision;
} else {
/* default LPC precision */
s->options.lpc_coeff_precision = 15;
}
av_log(avctx, AV_LOG_DEBUG, " lpc precision: %d\n",
s->options.lpc_coeff_precision);
/* set maximum encoded frame size in verbatim mode */
s->max_framesize = ff_flac_get_max_frame_size(s->avctx->frame_size,
s->channels, 16);
/* initialize MD5 context */
s->md5ctx = av_malloc(av_md5_size);
if(!s->md5ctx)
return AVERROR_NOMEM;
av_md5_init(s->md5ctx);
streaminfo = av_malloc(FLAC_STREAMINFO_SIZE);
write_streaminfo(s, streaminfo);
avctx->extradata = streaminfo;
avctx->extradata_size = FLAC_STREAMINFO_SIZE;
s->frame_count = 0;
s->min_framesize = s->max_framesize;
avctx->coded_frame = avcodec_alloc_frame();
avctx->coded_frame->key_frame = 1;
return 0;
}
static void init_frame(FlacEncodeContext *s)
{
int i, ch;
FlacFrame *frame;
frame = &s->frame;
for(i=0; i<16; i++) {
if(s->avctx->frame_size == ff_flac_blocksize_table[i]) {
frame->blocksize = ff_flac_blocksize_table[i];
frame->bs_code[0] = i;
frame->bs_code[1] = 0;
break;
}
}
if(i == 16) {
frame->blocksize = s->avctx->frame_size;
if(frame->blocksize <= 256) {
frame->bs_code[0] = 6;
frame->bs_code[1] = frame->blocksize-1;
} else {
frame->bs_code[0] = 7;
frame->bs_code[1] = frame->blocksize-1;
}
}
for(ch=0; ch<s->channels; ch++) {
frame->subframes[ch].obits = 16;
}
}
/**
* Copy channel-interleaved input samples into separate subframes
*/
static void copy_samples(FlacEncodeContext *s, int16_t *samples)
{
int i, j, ch;
FlacFrame *frame;
frame = &s->frame;
for(i=0,j=0; i<frame->blocksize; i++) {
for(ch=0; ch<s->channels; ch++,j++) {
frame->subframes[ch].samples[i] = samples[j];
}
}
}
#define rice_encode_count(sum, n, k) (((n)*((k)+1))+((sum-(n>>1))>>(k)))
/**
* Solve for d/dk(rice_encode_count) = n-((sum-(n>>1))>>(k+1)) = 0
*/
static int find_optimal_param(uint32_t sum, int n)
{
int k;
uint32_t sum2;
if(sum <= n>>1)
return 0;
sum2 = sum-(n>>1);
k = av_log2(n<256 ? FASTDIV(sum2,n) : sum2/n);
return FFMIN(k, MAX_RICE_PARAM);
}
static uint32_t calc_optimal_rice_params(RiceContext *rc, int porder,
uint32_t *sums, int n, int pred_order)
{
int i;
int k, cnt, part;
uint32_t all_bits;
part = (1 << porder);
all_bits = 4 * part;
cnt = (n >> porder) - pred_order;
for(i=0; i<part; i++) {
k = find_optimal_param(sums[i], cnt);
rc->params[i] = k;
all_bits += rice_encode_count(sums[i], cnt, k);
cnt = n >> porder;
}
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++) {
uint32_t sum = 0;
while(res < res_end){
sum += *(res++);
}
sums[pmax][i] = sum;
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;
}
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){
int a = smp[order-1] - smp[order-2];
for(i=order; i<n; i+=2) {
int b = smp[i] - smp[i-1];
res[i]= b - a;
a = smp[i+1] - smp[i];
res[i+1]= a - b;
}
}else if(order==3){
int a = smp[order-1] - smp[order-2];
int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
for(i=order; i<n; i+=2) {
int b = smp[i] - smp[i-1];
int d = b - a;
res[i]= d - c;
a = smp[i+1] - smp[i];
c = a - b;
res[i+1]= c - d;
}
}else{
int a = smp[order-1] - smp[order-2];
int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
int e = smp[order-1] - 3*smp[order-2] + 3*smp[order-3] - smp[order-4];
for(i=order; i<n; i+=2) {
int b = smp[i] - smp[i-1];
int d = b - a;
int f = d - c;
res[i]= f - e;
a = smp[i+1] - smp[i];
c = a - b;
e = c - d;
res[i+1]= e - f;
}
}
}
#define LPC1(x) {\
int c = coefs[(x)-1];\
p0 += c*s;\
s = smp[i-(x)+1];\
p1 += c*s;\
}
static av_always_inline void encode_residual_lpc_unrolled(
int32_t *res, const int32_t *smp, int n,
int order, const int32_t *coefs, int shift, int big)
{
int i;
for(i=order; i<n; i+=2) {
int s = smp[i-order];
int p0 = 0, p1 = 0;
if(big) {
switch(order) {
case 32: LPC1(32)
case 31: LPC1(31)
case 30: LPC1(30)
case 29: LPC1(29)
case 28: LPC1(28)
case 27: LPC1(27)
case 26: LPC1(26)
case 25: LPC1(25)
case 24: LPC1(24)
case 23: LPC1(23)
case 22: LPC1(22)
case 21: LPC1(21)
case 20: LPC1(20)
case 19: LPC1(19)
case 18: LPC1(18)
case 17: LPC1(17)
case 16: LPC1(16)
case 15: LPC1(15)
case 14: LPC1(14)
case 13: LPC1(13)
case 12: LPC1(12)
case 11: LPC1(11)
case 10: LPC1(10)
case 9: LPC1( 9)
LPC1( 8)
LPC1( 7)
LPC1( 6)
LPC1( 5)
LPC1( 4)
LPC1( 3)
LPC1( 2)
LPC1( 1)
}
} else {
switch(order) {
case 8: LPC1( 8)
case 7: LPC1( 7)
case 6: LPC1( 6)
case 5: LPC1( 5)
case 4: LPC1( 4)
case 3: LPC1( 3)
case 2: LPC1( 2)
case 1: LPC1( 1)
}
}
res[i ] = smp[i ] - (p0 >> shift);
res[i+1] = smp[i+1] - (p1 >> shift);
}
}
static void encode_residual_lpc(int32_t *res, const int32_t *smp, int n,
int order, const int32_t *coefs, int shift)
{
int i;
for(i=0; i<order; i++) {
res[i] = smp[i];
}
#if CONFIG_SMALL
for(i=order; i<n; i+=2) {
int j;
int s = smp[i];
int p0 = 0, p1 = 0;
for(j=0; j<order; j++) {
int c = coefs[j];
p1 += c*s;
s = smp[i-j-1];
p0 += c*s;
}
res[i ] = smp[i ] - (p0 >> shift);
res[i+1] = smp[i+1] - (p1 >> shift);
}
#else
switch(order) {
case 1: encode_residual_lpc_unrolled(res, smp, n, 1, coefs, shift, 0); break;
case 2: encode_residual_lpc_unrolled(res, smp, n, 2, coefs, shift, 0); break;
case 3: encode_residual_lpc_unrolled(res, smp, n, 3, coefs, shift, 0); break;
case 4: encode_residual_lpc_unrolled(res, smp, n, 4, coefs, shift, 0); break;
case 5: encode_residual_lpc_unrolled(res, smp, n, 5, coefs, shift, 0); break;
case 6: encode_residual_lpc_unrolled(res, smp, n, 6, coefs, shift, 0); break;
case 7: encode_residual_lpc_unrolled(res, smp, n, 7, coefs, shift, 0); break;
case 8: encode_residual_lpc_unrolled(res, smp, n, 8, coefs, shift, 0); break;
default: encode_residual_lpc_unrolled(res, smp, n, order, coefs, shift, 1); break;
}
#endif
}
static int encode_residual(FlacEncodeContext *ctx, int ch)
{
int i, n;
int min_order, max_order, opt_order, precision, omethod;
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;
omethod = ctx->options.prediction_order_method;
/* 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 */
opt_order = ff_lpc_calc_coefs(&ctx->dsp, smp, n, min_order, max_order,
precision, coefs, shift, ctx->options.use_lpc,
omethod, MAX_LPC_SHIFT, 0);
if(omethod == ORDER_METHOD_2LEVEL ||
omethod == ORDER_METHOD_4LEVEL ||
omethod == ORDER_METHOD_8LEVEL) {
int levels = 1 << omethod;
uint32_t bits[levels];
int order;
int opt_index = levels-1;
opt_order = max_order-1;
bits[opt_index] = UINT32_MAX;
for(i=levels-1; i>=0; i--) {
order = min_order + (((max_order-min_order+1) * (i+1)) / levels)-1;
if(order < 0) order = 0;
encode_residual_lpc(res, smp, n, order+1, coefs[order], shift[order]);
bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
res, n, order+1, sub->obits, precision);
if(bits[i] < bits[opt_index]) {
opt_index = i;
opt_order = order;
}
}
opt_order++;
} else if(omethod == ORDER_METHOD_SEARCH) {
// brute-force optimal order search
uint32_t bits[MAX_LPC_ORDER];
opt_order = 0;
bits[0] = UINT32_MAX;
for(i=min_order-1; i<max_order; i++) {
encode_residual_lpc(res, smp, n, i+1, coefs[i], shift[i]);
bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
res, n, i+1, sub->obits, precision);
if(bits[i] < bits[opt_order]) {
opt_order = i;
}
}
opt_order++;
} else if(omethod == ORDER_METHOD_LOG) {
uint32_t bits[MAX_LPC_ORDER];
int step;
opt_order= min_order - 1 + (max_order-min_order)/3;
memset(bits, -1, sizeof(bits));
for(step=16 ;step; step>>=1){
int last= opt_order;
for(i=last-step; i<=last+step; i+= step){
if(i<min_order-1 || i>=max_order || bits[i] < UINT32_MAX)
continue;
encode_residual_lpc(res, smp, n, i+1, coefs[i], shift[i]);
bits[i] = calc_rice_params_lpc(&sub->rc, min_porder, max_porder,
res, n, i+1, sub->obits, precision);
if(bits[i] < bits[opt_order])
opt_order= i;
}
}
opt_order++;
}
sub->order = opt_order;
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] += FFABS((lt + rt) >> 1);
sum[3] += FFABS(lt - rt);
sum[0] += FFABS(lt);
sum[1] += FFABS(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_INDEPENDENT;
} 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_INDEPENDENT;
return;
}
frame->ch_mode = estimate_stereo_mode(left, right, n);
/* perform decorrelation and adjust bits-per-sample */
if(frame->ch_mode == FLAC_CHMODE_INDEPENDENT) {
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 write_utf8(PutBitContext *pb, uint32_t val)
{
uint8_t tmp;
PUT_UTF8(val, tmp, put_bits(pb, 8, tmp);)
}
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_INDEPENDENT) {
put_bits(&s->pb, 4, s->channels-1);
} 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_crc_get_table(AV_CRC_8_ATM), 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_crc_get_table(AV_CRC_16_ANSI), 0,
s->pb.buf, put_bits_count(&s->pb)>>3));
put_bits(&s->pb, 16, crc);
flush_put_bits(&s->pb);
}
static void update_md5_sum(FlacEncodeContext *s, int16_t *samples)
{
#if HAVE_BIGENDIAN
int i;
for(i = 0; i < s->frame.blocksize*s->channels; i++) {
int16_t smp = le2me_16(samples[i]);
av_md5_update(s->md5ctx, (uint8_t *)&smp, 2);
}
#else
av_md5_update(s->md5ctx, (uint8_t *)samples, s->frame.blocksize*s->channels*2);
#endif
}
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;
int reencoded=0;
s = avctx->priv_data;
if(buf_size < s->max_framesize*2) {
av_log(avctx, AV_LOG_ERROR, "output buffer too small\n");
return 0;
}
/* when the last block is reached, update the header in extradata */
if (!data) {
s->max_framesize = s->max_encoded_framesize;
av_md5_final(s->md5ctx, s->md5sum);
write_streaminfo(s, avctx->extradata);
return 0;
}
init_frame(s);
copy_samples(s, samples);
channel_decorrelation(s);
for(ch=0; ch<s->channels; ch++) {
encode_residual(s, ch);
}
write_frame:
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) {
if(reencoded) {
/* still too large. must be an error. */
av_log(avctx, AV_LOG_ERROR, "error encoding frame\n");
return -1;
}
/* frame too large. use verbatim mode */
for(ch=0; ch<s->channels; ch++) {
encode_residual_v(s, ch);
}
reencoded = 1;
goto write_frame;
}
s->frame_count++;
s->sample_count += avctx->frame_size;
update_md5_sum(s, samples);
if (out_bytes > s->max_encoded_framesize)
s->max_encoded_framesize = out_bytes;
if (out_bytes < s->min_framesize)
s->min_framesize = out_bytes;
return out_bytes;
}
static av_cold int flac_encode_close(AVCodecContext *avctx)
{
if (avctx->priv_data) {
FlacEncodeContext *s = avctx->priv_data;
av_freep(&s->md5ctx);
}
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 | CODEC_CAP_DELAY,
.sample_fmts = (const enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
.long_name = NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),
};
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