diff options
Diffstat (limited to 'contrib/ffmpeg/libavcodec/flacenc.c')
| -rw-r--r-- | contrib/ffmpeg/libavcodec/flacenc.c | 1371 |
1 files changed, 1371 insertions, 0 deletions
diff --git a/contrib/ffmpeg/libavcodec/flacenc.c b/contrib/ffmpeg/libavcodec/flacenc.c new file mode 100644 index 000000000..b7b7d0d8e --- /dev/null +++ b/contrib/ffmpeg/libavcodec/flacenc.c @@ -0,0 +1,1371 @@ +/** + * FLAC audio encoder + * Copyright (c) 2006 Justin Ruggles <jruggle@earthlink.net> + * + * 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 "avcodec.h" +#include "bitstream.h" +#include "crc.h" +#include "golomb.h" +#include "lls.h" + +#define FLAC_MAX_CH 8 +#define FLAC_MIN_BLOCKSIZE 16 +#define FLAC_MAX_BLOCKSIZE 65535 + +#define FLAC_SUBFRAME_CONSTANT 0 +#define FLAC_SUBFRAME_VERBATIM 1 +#define FLAC_SUBFRAME_FIXED 8 +#define FLAC_SUBFRAME_LPC 32 + +#define FLAC_CHMODE_NOT_STEREO 0 +#define FLAC_CHMODE_LEFT_RIGHT 1 +#define FLAC_CHMODE_LEFT_SIDE 8 +#define FLAC_CHMODE_RIGHT_SIDE 9 +#define FLAC_CHMODE_MID_SIDE 10 + +#define ORDER_METHOD_EST 0 +#define ORDER_METHOD_2LEVEL 1 +#define ORDER_METHOD_4LEVEL 2 +#define ORDER_METHOD_8LEVEL 3 +#define ORDER_METHOD_SEARCH 4 +#define ORDER_METHOD_LOG 5 + +#define FLAC_STREAMINFO_SIZE 34 + +#define MIN_LPC_ORDER 1 +#define MAX_LPC_ORDER 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]; +} FlacSubframe; + +typedef struct FlacFrame { + FlacSubframe subframes[FLAC_MAX_CH]; + int blocksize; + int bs_code[2]; + uint8_t crc8; + int ch_mode; +} FlacFrame; + +typedef struct FlacEncodeContext { + PutBitContext pb; + int channels; + int ch_code; + int samplerate; + int sr_code[2]; + int blocksize; + int max_framesize; + uint32_t frame_count; + FlacFrame frame; + CompressionOptions options; + AVCodecContext *avctx; +} FlacEncodeContext; + +static const int flac_samplerates[16] = { + 0, 0, 0, 0, + 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000, + 0, 0, 0, 0 +}; + +static const int flac_blocksizes[16] = { + 0, + 192, + 576, 1152, 2304, 4608, + 0, 0, + 256, 512, 1024, 2048, 4096, 8192, 16384, 32768 +}; + +/** + * 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->blocksize); + put_bits(&pb, 16, s->blocksize); + put_bits(&pb, 24, 0); + 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 */ + flush_put_bits(&pb); + /* total samples = 0 */ + /* MD5 signature = 0 */ +} + +/** + * 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 = flac_blocksizes[1]; + target = (samplerate * block_time_ms) / 1000; + for(i=0; i<16; i++) { + if(target >= flac_blocksizes[i] && flac_blocksizes[i] > blocksize) { + blocksize = flac_blocksizes[i]; + } + } + return blocksize; +} + +static 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; + + if(avctx->sample_fmt != SAMPLE_FMT_S16) { + return -1; + } + + if(channels < 1 || channels > FLAC_MAX_CH) { + return -1; + } + s->channels = channels; + s->ch_code = s->channels-1; + + /* find samplerate in table */ + if(freq < 1) + return -1; + for(i=4; i<12; i++) { + if(freq == flac_samplerates[i]) { + s->samplerate = flac_samplerates[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 = 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; + } + s->blocksize = avctx->frame_size; + } else { + s->blocksize = select_blocksize(s->samplerate, s->options.block_time_ms); + avctx->frame_size = s->blocksize; + } + av_log(avctx, AV_LOG_DEBUG, " block size: %d\n", s->blocksize); + + /* 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 { + /* select LPC precision based on block size */ + if( s->blocksize <= 192) s->options.lpc_coeff_precision = 7; + else if(s->blocksize <= 384) s->options.lpc_coeff_precision = 8; + else if(s->blocksize <= 576) s->options.lpc_coeff_precision = 9; + else if(s->blocksize <= 1152) s->options.lpc_coeff_precision = 10; + else if(s->blocksize <= 2304) s->options.lpc_coeff_precision = 11; + else if(s->blocksize <= 4608) s->options.lpc_coeff_precision = 12; + else if(s->blocksize <= 8192) s->options.lpc_coeff_precision = 13; + else if(s->blocksize <= 16384) s->options.lpc_coeff_precision = 14; + else 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 */ + if(s->channels == 2) { + s->max_framesize = 14 + ((s->blocksize * 33 + 7) >> 3); + } else { + s->max_framesize = 14 + (s->blocksize * s->channels * 2); + } + + streaminfo = av_malloc(FLAC_STREAMINFO_SIZE); + write_streaminfo(s, streaminfo); + avctx->extradata = streaminfo; + avctx->extradata_size = FLAC_STREAMINFO_SIZE; + + s->frame_count = 0; + + 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->blocksize == flac_blocksizes[i]) { + frame->blocksize = flac_blocksizes[i]; + frame->bs_code[0] = i; + frame->bs_code[1] = 0; + break; + } + } + if(i == 16) { + frame->blocksize = s->blocksize; + 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))) + +static int find_optimal_param(uint32_t sum, int n) +{ + int k, k_opt; + uint32_t nbits[MAX_RICE_PARAM+1]; + + k_opt = 0; + nbits[0] = UINT32_MAX; + for(k=0; k<=MAX_RICE_PARAM; k++) { + nbits[k] = rice_encode_count(sum, n, k); + if(nbits[k] < nbits[k_opt]) { + k_opt = k; + } + } + return k_opt; +} + +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 = 0; + + cnt = (n >> porder) - pred_order; + for(i=0; i<part; i++) { + if(i == 1) cnt = (n >> porder); + k = find_optimal_param(sums[i], cnt); + 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, error; + 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 */ + error=0; + for(i=0; i<order; i++) { + error += lpc_in[i] * (1 << sh); + lpc_out[i] = clip(lrintf(error), -qmax, qmax); + error -= lpc_out[i]; + } + *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, int use_lpc, int omethod) +{ + double autoc[MAX_LPC_ORDER+1]; + double ref[MAX_LPC_ORDER]; + double lpc[MAX_LPC_ORDER][MAX_LPC_ORDER]; + int i, j, pass; + int opt_order; + + assert(max_order >= MIN_LPC_ORDER && max_order <= MAX_LPC_ORDER); + + if(use_lpc == 1){ + compute_autocorr(samples, blocksize, max_order+1, autoc); + + compute_lpc_coefs(autoc, max_order, lpc, ref); + }else{ + LLSModel m[2]; + double var[MAX_LPC_ORDER+1], eval, weight; + + for(pass=0; pass<use_lpc-1; pass++){ + av_init_lls(&m[pass&1], max_order); + + weight=0; + for(i=max_order; i<blocksize; i++){ + for(j=0; j<=max_order; j++) + var[j]= samples[i-j]; + + if(pass){ + eval= av_evaluate_lls(&m[(pass-1)&1], var+1, max_order-1); + eval= (512>>pass) + fabs(eval - var[0]); + for(j=0; j<=max_order; j++) + var[j]/= sqrt(eval); + weight += 1/eval; + }else + weight++; + + av_update_lls(&m[pass&1], var, 1.0); + } + av_solve_lls(&m[pass&1], 0.001, 0); + } + + for(i=0; i<max_order; i++){ + for(j=0; j<max_order; j++) + lpc[i][j]= m[(pass-1)&1].coeff[i][j]; + ref[i]= sqrt(m[(pass-1)&1].variance[i] / weight) * (blocksize - max_order) / 4000; + } + for(i=max_order-1; i>0; i--) + ref[i] = ref[i-1] - ref[i]; + } + opt_order = max_order; + + if(omethod == ORDER_METHOD_EST) { + opt_order = estimate_best_order(ref, max_order); + i = opt_order-1; + quantize_lpc_coefs(lpc[i], i+1, precision, coefs[i], &shift[i]); + } else { + for(i=0; i<max_order; i++) { + 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, 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 = lpc_calc_coefs(smp, n, max_order, precision, coefs, shift, ctx->options.use_lpc, omethod); + + 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_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) +{ + 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_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, +}; |