/** * FLAC audio encoder * Copyright (c) 2006 Justin Ruggles * * 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 "libavutil/opt.h" #include "avcodec.h" #include "get_bits.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; enum FFLPCType lpc_type; int lpc_passes; 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; int verbatim_only; } FlacFrame; typedef struct FlacEncodeContext { AVClass *class; 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; LPCContext lpc_ctx; struct AVMD5 *md5ctx; } FlacEncodeContext; /** * Write 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); } /** * Set blocksize based on samplerate. * Choose 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 void dprint_compression_options(FlacEncodeContext *s) { AVCodecContext *avctx = s->avctx; CompressionOptions *opt = &s->options; av_log(avctx, AV_LOG_DEBUG, " compression: %d\n", opt->compression_level); switch (opt->lpc_type) { case FF_LPC_TYPE_NONE: av_log(avctx, AV_LOG_DEBUG, " lpc type: None\n"); break; case FF_LPC_TYPE_FIXED: av_log(avctx, AV_LOG_DEBUG, " lpc type: Fixed pre-defined coefficients\n"); break; case FF_LPC_TYPE_LEVINSON: av_log(avctx, AV_LOG_DEBUG, " lpc type: Levinson-Durbin recursion with Welch window\n"); break; case FF_LPC_TYPE_CHOLESKY: av_log(avctx, AV_LOG_DEBUG, " lpc type: Cholesky factorization, %d pass%s\n", opt->lpc_passes, opt->lpc_passes == 1 ? "" : "es"); break; } av_log(avctx, AV_LOG_DEBUG, " prediction order: %d, %d\n", opt->min_prediction_order, opt->max_prediction_order); switch (opt->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; } av_log(avctx, AV_LOG_DEBUG, " partition order: %d, %d\n", opt->min_partition_order, opt->max_partition_order); av_log(avctx, AV_LOG_DEBUG, " block size: %d\n", avctx->frame_size); av_log(avctx, AV_LOG_DEBUG, " lpc precision: %d\n", opt->lpc_coeff_precision); } 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, ret; uint8_t *streaminfo; s->avctx = avctx; if (avctx->sample_fmt != AV_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; 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]; if (s->options.lpc_type == FF_LPC_TYPE_DEFAULT) s->options.lpc_type = ((int[]){ FF_LPC_TYPE_FIXED, FF_LPC_TYPE_FIXED, FF_LPC_TYPE_FIXED, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON})[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]; if (s->options.prediction_order_method < 0) 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]; if (s->options.min_partition_order > s->options.max_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 AVERROR(EINVAL); } if (s->options.min_partition_order < 0) s->options.min_partition_order = ((int[]){ 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0})[level]; if (s->options.max_partition_order < 0) 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 FF_API_FLAC_GLOBAL_OPTS if (avctx->lpc_type > FF_LPC_TYPE_DEFAULT) { if (avctx->lpc_type > FF_LPC_TYPE_CHOLESKY) { av_log(avctx, AV_LOG_ERROR, "unknown lpc type: %d\n", avctx->lpc_type); return -1; } s->options.lpc_type = avctx->lpc_type; if (s->options.lpc_type == FF_LPC_TYPE_CHOLESKY) { if (avctx->lpc_passes < 0) { // default number of passes for Cholesky s->options.lpc_passes = 2; } else if (avctx->lpc_passes == 0) { av_log(avctx, AV_LOG_ERROR, "invalid number of lpc passes: %d\n", avctx->lpc_passes); return -1; } else { s->options.lpc_passes = avctx->lpc_passes; } } } #endif if (s->options.lpc_type == FF_LPC_TYPE_NONE) { s->options.min_prediction_order = 0; } else if (avctx->min_prediction_order >= 0) { if (s->options.lpc_type == FF_LPC_TYPE_FIXED) { 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; } } else 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; } s->options.min_prediction_order = avctx->min_prediction_order; } if (s->options.lpc_type == FF_LPC_TYPE_NONE) { s->options.max_prediction_order = 0; } else if (avctx->max_prediction_order >= 0) { if (s->options.lpc_type == FF_LPC_TYPE_FIXED) { 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; } } else 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; } 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; } #if FF_API_FLAC_GLOBAL_OPTS 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; } 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; } #endif 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; #if FF_API_FLAC_GLOBAL_OPTS /* 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; } #endif /* 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(ENOMEM); av_md5_init(s->md5ctx); streaminfo = av_malloc(FLAC_STREAMINFO_SIZE); if (!streaminfo) return AVERROR(ENOMEM); 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(); if (!avctx->coded_frame) return AVERROR(ENOMEM); if (channels == 3 && avctx->channel_layout != (AV_CH_LAYOUT_STEREO|AV_CH_FRONT_CENTER) || channels == 4 && avctx->channel_layout != AV_CH_LAYOUT_2_2 && avctx->channel_layout != AV_CH_LAYOUT_QUAD || channels == 5 && avctx->channel_layout != AV_CH_LAYOUT_5POINT0 && avctx->channel_layout != AV_CH_LAYOUT_5POINT0_BACK || channels == 6 && avctx->channel_layout != AV_CH_LAYOUT_5POINT1 && avctx->channel_layout != AV_CH_LAYOUT_5POINT1_BACK) { if (avctx->channel_layout) { av_log(avctx, AV_LOG_ERROR, "Channel layout not supported by Flac, " "output stream will have incorrect " "channel layout.\n"); } else { av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The encoder " "will use Flac channel layout for " "%d channels.\n", channels); } } ret = ff_lpc_init(&s->lpc_ctx, avctx->frame_size, s->options.max_prediction_order, FF_LPC_TYPE_LEVINSON); dprint_compression_options(s); return ret; } 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; frame->verbatim_only = 0; } /** * Copy channel-interleaved input samples into separate subframes. */ static void copy_samples(FlacEncodeContext *s, const 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]; } static int rice_count_exact(int32_t *res, int n, int k) { int i; int count = 0; for (i = 0; i < n; i++) { int32_t v = -2 * res[i] - 1; v ^= v >> 31; count += (v >> k) + 1 + k; } return count; } static int subframe_count_exact(FlacEncodeContext *s, FlacSubframe *sub, int pred_order) { int p, porder, psize; int i, part_end; int count = 0; /* subframe header */ count += 8; /* subframe */ if (sub->type == FLAC_SUBFRAME_CONSTANT) { count += sub->obits; } else if (sub->type == FLAC_SUBFRAME_VERBATIM) { count += s->frame.blocksize * sub->obits; } else { /* warm-up samples */ count += pred_order * sub->obits; /* LPC coefficients */ if (sub->type == FLAC_SUBFRAME_LPC) count += 4 + 5 + pred_order * s->options.lpc_coeff_precision; /* rice-encoded block */ count += 2; /* partition order */ porder = sub->rc.porder; psize = s->frame.blocksize >> porder; count += 4; /* residual */ i = pred_order; part_end = psize; for (p = 0; p < 1 << porder; p++) { int k = sub->rc.params[p]; count += 4; count += rice_count_exact(&sub->residual[i], part_end - i, k); i = part_end; part_end = FFMIN(s->frame.blocksize, part_end + psize); } } return count; } #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 find_subframe_rice_params(FlacEncodeContext *s, FlacSubframe *sub, int pred_order) { int pmin = get_max_p_order(s->options.min_partition_order, s->frame.blocksize, pred_order); int pmax = get_max_p_order(s->options.max_partition_order, s->frame.blocksize, pred_order); uint32_t bits = 8 + pred_order * sub->obits + 2 + 4; if (sub->type == FLAC_SUBFRAME_LPC) bits += 4 + 5 + pred_order * s->options.lpc_coeff_precision; bits += calc_rice_params(&sub->rc, pmin, pmax, sub->residual, s->frame.blocksize, pred_order); return bits; } 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_ch(FlacEncodeContext *s, int ch) { int i, n; int min_order, max_order, opt_order, omethod; FlacFrame *frame; FlacSubframe *sub; int32_t coefs[MAX_LPC_ORDER][MAX_LPC_ORDER]; int shift[MAX_LPC_ORDER]; int32_t *res, *smp; frame = &s->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 subframe_count_exact(s, sub, 0); } /* VERBATIM */ if (frame->verbatim_only || n < 5) { sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM; memcpy(res, smp, n * sizeof(int32_t)); return subframe_count_exact(s, sub, 0); } min_order = s->options.min_prediction_order; max_order = s->options.max_prediction_order; omethod = s->options.prediction_order_method; /* FIXED */ sub->type = FLAC_SUBFRAME_FIXED; if (s->options.lpc_type == FF_LPC_TYPE_NONE || s->options.lpc_type == FF_LPC_TYPE_FIXED || 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] = find_subframe_rice_params(s, sub, i); if (bits[i] < bits[opt_order]) opt_order = i; } sub->order = opt_order; sub->type_code = sub->type | sub->order; if (sub->order != max_order) { encode_residual_fixed(res, smp, n, sub->order); find_subframe_rice_params(s, sub, sub->order); } return subframe_count_exact(s, sub, sub->order); } /* LPC */ sub->type = FLAC_SUBFRAME_LPC; opt_order = ff_lpc_calc_coefs(&s->lpc_ctx, smp, n, min_order, max_order, s->options.lpc_coeff_precision, coefs, shift, s->options.lpc_type, s->options.lpc_passes, 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[1 << ORDER_METHOD_8LEVEL]; int order = -1; int opt_index = levels-1; opt_order = max_order-1; bits[opt_index] = UINT32_MAX; for (i = levels-1; i >= 0; i--) { int last_order = order; order = min_order + (((max_order-min_order+1) * (i+1)) / levels)-1; order = av_clip(order, min_order - 1, max_order - 1); if (order == last_order) continue; encode_residual_lpc(res, smp, n, order+1, coefs[order], shift[order]); bits[i] = find_subframe_rice_params(s, sub, order+1); 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] = find_subframe_rice_params(s, sub, i+1); 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] = find_subframe_rice_params(s, sub, i+1); if (bits[i] < bits[opt_order]) opt_order = i; } } opt_order++; } sub->order = opt_order; 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); find_subframe_rice_params(s, sub, sub->order); return subframe_count_exact(s, sub, sub->order); } static int count_frame_header(FlacEncodeContext *s) { uint8_t av_unused tmp; int count; /* <14> Sync code <1> Reserved <1> Blocking strategy <4> Block size in inter-channel samples <4> Sample rate <4> Channel assignment <3> Sample size in bits <1> Reserved */ count = 32; /* coded frame number */ PUT_UTF8(s->frame_count, tmp, count += 8;) /* explicit block size */ if (s->frame.bs_code[0] == 6) count += 8; else if (s->frame.bs_code[0] == 7) count += 16; /* explicit sample rate */ count += ((s->sr_code[0] == 12) + (s->sr_code[0] > 12)) * 8; /* frame header CRC-8 */ count += 8; return count; } static int encode_frame(FlacEncodeContext *s) { int ch, count; count = count_frame_header(s); for (ch = 0; ch < s->channels; ch++) count += encode_residual_ch(s, ch); count += (8 - (count & 7)) & 7; // byte alignment count += 16; // CRC-16 return count >> 3; } 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 *s) { FlacFrame *frame; int32_t *left, *right; int i, n; frame = &s->frame; n = frame->blocksize; left = frame->subframes[0].samples; right = frame->subframes[1].samples; if (s->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 write_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 write_subframes(FlacEncodeContext *s) { int ch; for (ch = 0; ch < s->channels; ch++) { FlacSubframe *sub = &s->frame.subframes[ch]; int i, p, porder, psize; int32_t *part_end; int32_t *res = sub->residual; int32_t *frame_end = &sub->residual[s->frame.blocksize]; /* 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) { put_sbits(&s->pb, sub->obits, res[0]); } else if (sub->type == FLAC_SUBFRAME_VERBATIM) { while (res < frame_end) put_sbits(&s->pb, sub->obits, *res++); } else { /* warm-up samples */ for (i = 0; i < sub->order; i++) put_sbits(&s->pb, sub->obits, *res++); /* LPC coefficients */ if (sub->type == FLAC_SUBFRAME_LPC) { int cbits = s->options.lpc_coeff_precision; put_bits( &s->pb, 4, cbits-1); put_sbits(&s->pb, 5, sub->shift); for (i = 0; i < sub->order; i++) put_sbits(&s->pb, cbits, sub->coefs[i]); } /* rice-encoded block */ put_bits(&s->pb, 2, 0); /* partition order */ porder = sub->rc.porder; psize = s->frame.blocksize >> porder; put_bits(&s->pb, 4, porder); /* residual */ part_end = &sub->residual[psize]; for (p = 0; p < 1 << porder; p++) { int k = sub->rc.params[p]; put_bits(&s->pb, 4, k); while (res < part_end) set_sr_golomb_flac(&s->pb, *res++, k, INT32_MAX, 0); part_end = FFMIN(frame_end, part_end + psize); } } } } static void write_frame_footer(FlacEncodeContext *s) { int crc; flush_put_bits(&s->pb); crc = av_bswap16(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 int write_frame(FlacEncodeContext *s, uint8_t *frame, int buf_size) { init_put_bits(&s->pb, frame, buf_size); write_frame_header(s); write_subframes(s); write_frame_footer(s); return put_bits_count(&s->pb) >> 3; } static void update_md5_sum(FlacEncodeContext *s, const int16_t *samples) { #if HAVE_BIGENDIAN int i; for (i = 0; i < s->frame.blocksize * s->channels; i++) { int16_t smp = av_le2ne16(samples[i]); av_md5_update(s->md5ctx, (uint8_t *)&smp, 2); } #else av_md5_update(s->md5ctx, (const 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) { FlacEncodeContext *s; const int16_t *samples = data; int frame_bytes, out_bytes; s = avctx->priv_data; /* 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; } /* change max_framesize for small final frame */ if (avctx->frame_size < s->frame.blocksize) { s->max_framesize = ff_flac_get_max_frame_size(avctx->frame_size, s->channels, 16); } init_frame(s); copy_samples(s, samples); channel_decorrelation(s); frame_bytes = encode_frame(s); /* fallback to verbatim mode if the compressed frame is larger than it would be if encoded uncompressed. */ if (frame_bytes > s->max_framesize) { s->frame.verbatim_only = 1; frame_bytes = encode_frame(s); } if (buf_size < frame_bytes) { av_log(avctx, AV_LOG_ERROR, "output buffer too small\n"); return 0; } out_bytes = write_frame(s, frame, buf_size); s->frame_count++; avctx->coded_frame->pts = s->sample_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); ff_lpc_end(&s->lpc_ctx); } av_freep(&avctx->extradata); avctx->extradata_size = 0; av_freep(&avctx->coded_frame); return 0; } #define FLAGS AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM static const AVOption options[] = { { "lpc_coeff_precision", "LPC coefficient precision", offsetof(FlacEncodeContext, options.lpc_coeff_precision), AV_OPT_TYPE_INT, {.dbl = 15 }, 0, MAX_LPC_PRECISION, FLAGS }, { "lpc_type", "LPC algorithm", offsetof(FlacEncodeContext, options.lpc_type), AV_OPT_TYPE_INT, {.dbl = FF_LPC_TYPE_DEFAULT }, FF_LPC_TYPE_DEFAULT, FF_LPC_TYPE_NB-1, FLAGS, "lpc_type" }, { "none", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = FF_LPC_TYPE_NONE }, INT_MIN, INT_MAX, FLAGS, "lpc_type" }, { "fixed", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = FF_LPC_TYPE_FIXED }, INT_MIN, INT_MAX, FLAGS, "lpc_type" }, { "levinson", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = FF_LPC_TYPE_LEVINSON }, INT_MIN, INT_MAX, FLAGS, "lpc_type" }, { "cholesky", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = FF_LPC_TYPE_CHOLESKY }, INT_MIN, INT_MAX, FLAGS, "lpc_type" }, { "lpc_passes", "Number of passes to use for Cholesky factorization during LPC analysis", offsetof(FlacEncodeContext, options.lpc_passes), AV_OPT_TYPE_INT, {.dbl = -1 }, INT_MIN, INT_MAX, FLAGS }, { "min_partition_order", NULL, offsetof(FlacEncodeContext, options.min_partition_order), AV_OPT_TYPE_INT, {.dbl = -1 }, -1, MAX_PARTITION_ORDER, FLAGS }, { "max_partition_order", NULL, offsetof(FlacEncodeContext, options.max_partition_order), AV_OPT_TYPE_INT, {.dbl = -1 }, -1, MAX_PARTITION_ORDER, FLAGS }, { "prediction_order_method", "Search method for selecting prediction order", offsetof(FlacEncodeContext, options.prediction_order_method), AV_OPT_TYPE_INT, {.dbl = -1 }, -1, ORDER_METHOD_LOG, FLAGS, "predm" }, { "estimation", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = ORDER_METHOD_EST }, INT_MIN, INT_MAX, FLAGS, "predm" }, { "2level", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = ORDER_METHOD_2LEVEL }, INT_MIN, INT_MAX, FLAGS, "predm" }, { "4level", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = ORDER_METHOD_4LEVEL }, INT_MIN, INT_MAX, FLAGS, "predm" }, { "8level", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = ORDER_METHOD_8LEVEL }, INT_MIN, INT_MAX, FLAGS, "predm" }, { "search", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = ORDER_METHOD_SEARCH }, INT_MIN, INT_MAX, FLAGS, "predm" }, { "log", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = ORDER_METHOD_LOG }, INT_MIN, INT_MAX, FLAGS, "predm" }, { NULL }, }; static const AVClass flac_encoder_class = { "FLAC encoder", av_default_item_name, options, LIBAVUTIL_VERSION_INT, }; AVCodec ff_flac_encoder = { .name = "flac", .type = AVMEDIA_TYPE_AUDIO, .id = CODEC_ID_FLAC, .priv_data_size = sizeof(FlacEncodeContext), .init = flac_encode_init, .encode = flac_encode_frame, .close = flac_encode_close, .capabilities = CODEC_CAP_SMALL_LAST_FRAME | CODEC_CAP_DELAY | CODEC_CAP_LOSSLESS, .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE}, .long_name = NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"), .priv_class = &flac_encoder_class, };