/* * Copyright (c) CMU 1993 Computer Science, Speech Group * Chengxiang Lu and Alex Hauptmann * Copyright (c) 2005 Steve Underwood <steveu at coppice.org> * Copyright (c) 2009 Kenan Gillet * Copyright (c) 2010 Martin Storsjo * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * G.722 ADPCM audio encoder */ #include "avcodec.h" #include "g722.h" #define FREEZE_INTERVAL 128 /* This is an arbitrary value. Allowing insanely large values leads to strange problems, so we limit it to a reasonable value */ #define MAX_FRAME_SIZE 32768 /* We clip the value of avctx->trellis to prevent data type overflows and undefined behavior. Using larger values is insanely slow anyway. */ #define MIN_TRELLIS 0 #define MAX_TRELLIS 16 static av_cold int g722_encode_close(AVCodecContext *avctx) { G722Context *c = avctx->priv_data; int i; for (i = 0; i < 2; i++) { av_freep(&c->paths[i]); av_freep(&c->node_buf[i]); av_freep(&c->nodep_buf[i]); } return 0; } static av_cold int g722_encode_init(AVCodecContext * avctx) { G722Context *c = avctx->priv_data; int ret; if (avctx->channels != 1) { av_log(avctx, AV_LOG_ERROR, "Only mono tracks are allowed.\n"); return AVERROR_INVALIDDATA; } c->band[0].scale_factor = 8; c->band[1].scale_factor = 2; c->prev_samples_pos = 22; if (avctx->trellis) { int frontier = 1 << avctx->trellis; int max_paths = frontier * FREEZE_INTERVAL; int i; for (i = 0; i < 2; i++) { c->paths[i] = av_mallocz(max_paths * sizeof(**c->paths)); c->node_buf[i] = av_mallocz(2 * frontier * sizeof(**c->node_buf)); c->nodep_buf[i] = av_mallocz(2 * frontier * sizeof(**c->nodep_buf)); if (!c->paths[i] || !c->node_buf[i] || !c->nodep_buf[i]) { ret = AVERROR(ENOMEM); goto error; } } } if (avctx->frame_size) { /* validate frame size */ if (avctx->frame_size & 1 || avctx->frame_size > MAX_FRAME_SIZE) { int new_frame_size; if (avctx->frame_size == 1) new_frame_size = 2; else if (avctx->frame_size > MAX_FRAME_SIZE) new_frame_size = MAX_FRAME_SIZE; else new_frame_size = avctx->frame_size - 1; av_log(avctx, AV_LOG_WARNING, "Requested frame size is not " "allowed. Using %d instead of %d\n", new_frame_size, avctx->frame_size); avctx->frame_size = new_frame_size; } } else { /* This is arbitrary. We use 320 because it's 20ms @ 16kHz, which is a common packet size for VoIP applications */ avctx->frame_size = 320; } if (avctx->trellis) { /* validate trellis */ if (avctx->trellis < MIN_TRELLIS || avctx->trellis > MAX_TRELLIS) { int new_trellis = av_clip(avctx->trellis, MIN_TRELLIS, MAX_TRELLIS); av_log(avctx, AV_LOG_WARNING, "Requested trellis value is not " "allowed. Using %d instead of %d\n", new_trellis, avctx->trellis); avctx->trellis = new_trellis; } } return 0; error: g722_encode_close(avctx); return ret; } static const int16_t low_quant[33] = { 35, 72, 110, 150, 190, 233, 276, 323, 370, 422, 473, 530, 587, 650, 714, 786, 858, 940, 1023, 1121, 1219, 1339, 1458, 1612, 1765, 1980, 2195, 2557, 2919 }; static inline void filter_samples(G722Context *c, const int16_t *samples, int *xlow, int *xhigh) { int xout1, xout2; c->prev_samples[c->prev_samples_pos++] = samples[0]; c->prev_samples[c->prev_samples_pos++] = samples[1]; ff_g722_apply_qmf(c->prev_samples + c->prev_samples_pos - 24, &xout1, &xout2); *xlow = xout1 + xout2 >> 14; *xhigh = xout1 - xout2 >> 14; if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) { memmove(c->prev_samples, c->prev_samples + c->prev_samples_pos - 22, 22 * sizeof(c->prev_samples[0])); c->prev_samples_pos = 22; } } static inline int encode_high(const struct G722Band *state, int xhigh) { int diff = av_clip_int16(xhigh - state->s_predictor); int pred = 141 * state->scale_factor >> 8; /* = diff >= 0 ? (diff < pred) + 2 : diff >= -pred */ return ((diff ^ (diff >> (sizeof(diff)*8-1))) < pred) + 2*(diff >= 0); } static inline int encode_low(const struct G722Band* state, int xlow) { int diff = av_clip_int16(xlow - state->s_predictor); /* = diff >= 0 ? diff : -(diff + 1) */ int limit = diff ^ (diff >> (sizeof(diff)*8-1)); int i = 0; limit = limit + 1 << 10; if (limit > low_quant[8] * state->scale_factor) i = 9; while (i < 29 && limit > low_quant[i] * state->scale_factor) i++; return (diff < 0 ? (i < 2 ? 63 : 33) : 61) - i; } static void g722_encode_trellis(G722Context *c, int trellis, uint8_t *dst, int nb_samples, const int16_t *samples) { int i, j, k; int frontier = 1 << trellis; struct TrellisNode **nodes[2]; struct TrellisNode **nodes_next[2]; int pathn[2] = {0, 0}, froze = -1; struct TrellisPath *p[2]; for (i = 0; i < 2; i++) { nodes[i] = c->nodep_buf[i]; nodes_next[i] = c->nodep_buf[i] + frontier; memset(c->nodep_buf[i], 0, 2 * frontier * sizeof(*c->nodep_buf)); nodes[i][0] = c->node_buf[i] + frontier; nodes[i][0]->ssd = 0; nodes[i][0]->path = 0; nodes[i][0]->state = c->band[i]; } for (i = 0; i < nb_samples >> 1; i++) { int xlow, xhigh; struct TrellisNode *next[2]; int heap_pos[2] = {0, 0}; for (j = 0; j < 2; j++) { next[j] = c->node_buf[j] + frontier*(i & 1); memset(nodes_next[j], 0, frontier * sizeof(**nodes_next)); } filter_samples(c, &samples[2*i], &xlow, &xhigh); for (j = 0; j < frontier && nodes[0][j]; j++) { /* Only k >> 2 affects the future adaptive state, therefore testing * small steps that don't change k >> 2 is useless, the original * value from encode_low is better than them. Since we step k * in steps of 4, make sure range is a multiple of 4, so that * we don't miss the original value from encode_low. */ int range = j < frontier/2 ? 4 : 0; struct TrellisNode *cur_node = nodes[0][j]; int ilow = encode_low(&cur_node->state, xlow); for (k = ilow - range; k <= ilow + range && k <= 63; k += 4) { int decoded, dec_diff, pos; uint32_t ssd; struct TrellisNode* node; if (k < 0) continue; decoded = av_clip((cur_node->state.scale_factor * ff_g722_low_inv_quant6[k] >> 10) + cur_node->state.s_predictor, -16384, 16383); dec_diff = xlow - decoded; #define STORE_NODE(index, UPDATE, VALUE)\ ssd = cur_node->ssd + dec_diff*dec_diff;\ /* Check for wraparound. Using 64 bit ssd counters would \ * be simpler, but is slower on x86 32 bit. */\ if (ssd < cur_node->ssd)\ continue;\ if (heap_pos[index] < frontier) {\ pos = heap_pos[index]++;\ assert(pathn[index] < FREEZE_INTERVAL * frontier);\ node = nodes_next[index][pos] = next[index]++;\ node->path = pathn[index]++;\ } else {\ /* Try to replace one of the leaf nodes with the new \ * one, but not always testing the same leaf position */\ pos = (frontier>>1) + (heap_pos[index] & ((frontier>>1) - 1));\ if (ssd >= nodes_next[index][pos]->ssd)\ continue;\ heap_pos[index]++;\ node = nodes_next[index][pos];\ }\ node->ssd = ssd;\ node->state = cur_node->state;\ UPDATE;\ c->paths[index][node->path].value = VALUE;\ c->paths[index][node->path].prev = cur_node->path;\ /* Sift the newly inserted node up in the heap to restore \ * the heap property */\ while (pos > 0) {\ int parent = (pos - 1) >> 1;\ if (nodes_next[index][parent]->ssd <= ssd)\ break;\ FFSWAP(struct TrellisNode*, nodes_next[index][parent],\ nodes_next[index][pos]);\ pos = parent;\ } STORE_NODE(0, ff_g722_update_low_predictor(&node->state, k >> 2), k); } } for (j = 0; j < frontier && nodes[1][j]; j++) { int ihigh; struct TrellisNode *cur_node = nodes[1][j]; /* We don't try to get any initial guess for ihigh via * encode_high - since there's only 4 possible values, test * them all. Testing all of these gives a much, much larger * gain than testing a larger range around ilow. */ for (ihigh = 0; ihigh < 4; ihigh++) { int dhigh, decoded, dec_diff, pos; uint32_t ssd; struct TrellisNode* node; dhigh = cur_node->state.scale_factor * ff_g722_high_inv_quant[ihigh] >> 10; decoded = av_clip(dhigh + cur_node->state.s_predictor, -16384, 16383); dec_diff = xhigh - decoded; STORE_NODE(1, ff_g722_update_high_predictor(&node->state, dhigh, ihigh), ihigh); } } for (j = 0; j < 2; j++) { FFSWAP(struct TrellisNode**, nodes[j], nodes_next[j]); if (nodes[j][0]->ssd > (1 << 16)) { for (k = 1; k < frontier && nodes[j][k]; k++) nodes[j][k]->ssd -= nodes[j][0]->ssd; nodes[j][0]->ssd = 0; } } if (i == froze + FREEZE_INTERVAL) { p[0] = &c->paths[0][nodes[0][0]->path]; p[1] = &c->paths[1][nodes[1][0]->path]; for (j = i; j > froze; j--) { dst[j] = p[1]->value << 6 | p[0]->value; p[0] = &c->paths[0][p[0]->prev]; p[1] = &c->paths[1][p[1]->prev]; } froze = i; pathn[0] = pathn[1] = 0; memset(nodes[0] + 1, 0, (frontier - 1)*sizeof(**nodes)); memset(nodes[1] + 1, 0, (frontier - 1)*sizeof(**nodes)); } } p[0] = &c->paths[0][nodes[0][0]->path]; p[1] = &c->paths[1][nodes[1][0]->path]; for (j = i; j > froze; j--) { dst[j] = p[1]->value << 6 | p[0]->value; p[0] = &c->paths[0][p[0]->prev]; p[1] = &c->paths[1][p[1]->prev]; } c->band[0] = nodes[0][0]->state; c->band[1] = nodes[1][0]->state; } static av_always_inline void encode_byte(G722Context *c, uint8_t *dst, const int16_t *samples) { int xlow, xhigh, ilow, ihigh; filter_samples(c, samples, &xlow, &xhigh); ihigh = encode_high(&c->band[1], xhigh); ilow = encode_low (&c->band[0], xlow); ff_g722_update_high_predictor(&c->band[1], c->band[1].scale_factor * ff_g722_high_inv_quant[ihigh] >> 10, ihigh); ff_g722_update_low_predictor(&c->band[0], ilow >> 2); *dst = ihigh << 6 | ilow; } static void g722_encode_no_trellis(G722Context *c, uint8_t *dst, int nb_samples, const int16_t *samples) { int i; for (i = 0; i < nb_samples; i += 2) encode_byte(c, dst++, &samples[i]); } static int g722_encode_frame(AVCodecContext *avctx, uint8_t *dst, int buf_size, void *data) { G722Context *c = avctx->priv_data; const int16_t *samples = data; int nb_samples; nb_samples = avctx->frame_size - (avctx->frame_size & 1); if (avctx->trellis) g722_encode_trellis(c, avctx->trellis, dst, nb_samples, samples); else g722_encode_no_trellis(c, dst, nb_samples, samples); /* handle last frame with odd frame_size */ if (nb_samples < avctx->frame_size) { int16_t last_samples[2] = { samples[nb_samples], samples[nb_samples] }; encode_byte(c, &dst[nb_samples >> 1], last_samples); } return (avctx->frame_size + 1) >> 1; } AVCodec ff_adpcm_g722_encoder = { .name = "g722", .type = AVMEDIA_TYPE_AUDIO, .id = CODEC_ID_ADPCM_G722, .priv_data_size = sizeof(G722Context), .init = g722_encode_init, .close = g722_encode_close, .encode = g722_encode_frame, .capabilities = CODEC_CAP_SMALL_LAST_FRAME, .long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"), .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE}, };