1/* 2 * Copyright (c) CMU 1993 Computer Science, Speech Group 3 * Chengxiang Lu and Alex Hauptmann 4 * Copyright (c) 2005 Steve Underwood <steveu at coppice.org> 5 * Copyright (c) 2009 Kenan Gillet 6 * Copyright (c) 2010 Martin Storsjo 7 * 8 * This file is part of FFmpeg. 9 * 10 * FFmpeg is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU Lesser General Public 12 * License as published by the Free Software Foundation; either 13 * version 2.1 of the License, or (at your option) any later version. 14 * 15 * FFmpeg is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * Lesser General Public License for more details. 19 * 20 * You should have received a copy of the GNU Lesser General Public 21 * License along with FFmpeg; if not, write to the Free Software 22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 23 */ 24 25/** 26 * @file 27 * G.722 ADPCM audio encoder 28 */ 29 30#include "libavutil/avassert.h" 31#include "avcodec.h" 32#include "internal.h" 33#include "g722.h" 34#include "libavutil/common.h" 35 36#define FREEZE_INTERVAL 128 37 38/* This is an arbitrary value. Allowing insanely large values leads to strange 39 problems, so we limit it to a reasonable value */ 40#define MAX_FRAME_SIZE 32768 41 42/* We clip the value of avctx->trellis to prevent data type overflows and 43 undefined behavior. Using larger values is insanely slow anyway. */ 44#define MIN_TRELLIS 0 45#define MAX_TRELLIS 16 46 47static av_cold int g722_encode_close(AVCodecContext *avctx) 48{ 49 G722Context *c = avctx->priv_data; 50 int i; 51 for (i = 0; i < 2; i++) { 52 av_freep(&c->paths[i]); 53 av_freep(&c->node_buf[i]); 54 av_freep(&c->nodep_buf[i]); 55 } 56 return 0; 57} 58 59static av_cold int g722_encode_init(AVCodecContext * avctx) 60{ 61 G722Context *c = avctx->priv_data; 62 int ret; 63 64 if (avctx->channels != 1) { 65 av_log(avctx, AV_LOG_ERROR, "Only mono tracks are allowed.\n"); 66 return AVERROR_INVALIDDATA; 67 } 68 69 c->band[0].scale_factor = 8; 70 c->band[1].scale_factor = 2; 71 c->prev_samples_pos = 22; 72 73 if (avctx->trellis) { 74 int frontier = 1 << avctx->trellis; 75 int max_paths = frontier * FREEZE_INTERVAL; 76 int i; 77 for (i = 0; i < 2; i++) { 78 c->paths[i] = av_mallocz(max_paths * sizeof(**c->paths)); 79 c->node_buf[i] = av_mallocz(2 * frontier * sizeof(**c->node_buf)); 80 c->nodep_buf[i] = av_mallocz(2 * frontier * sizeof(**c->nodep_buf)); 81 if (!c->paths[i] || !c->node_buf[i] || !c->nodep_buf[i]) { 82 ret = AVERROR(ENOMEM); 83 goto error; 84 } 85 } 86 } 87 88 if (avctx->frame_size) { 89 /* validate frame size */ 90 if (avctx->frame_size & 1 || avctx->frame_size > MAX_FRAME_SIZE) { 91 int new_frame_size; 92 93 if (avctx->frame_size == 1) 94 new_frame_size = 2; 95 else if (avctx->frame_size > MAX_FRAME_SIZE) 96 new_frame_size = MAX_FRAME_SIZE; 97 else 98 new_frame_size = avctx->frame_size - 1; 99 100 av_log(avctx, AV_LOG_WARNING, "Requested frame size is not " 101 "allowed. Using %d instead of %d\n", new_frame_size, 102 avctx->frame_size); 103 avctx->frame_size = new_frame_size; 104 } 105 } else { 106 /* This is arbitrary. We use 320 because it's 20ms @ 16kHz, which is 107 a common packet size for VoIP applications */ 108 avctx->frame_size = 320; 109 } 110 avctx->delay = 22; 111 112 if (avctx->trellis) { 113 /* validate trellis */ 114 if (avctx->trellis < MIN_TRELLIS || avctx->trellis > MAX_TRELLIS) { 115 int new_trellis = av_clip(avctx->trellis, MIN_TRELLIS, MAX_TRELLIS); 116 av_log(avctx, AV_LOG_WARNING, "Requested trellis value is not " 117 "allowed. Using %d instead of %d\n", new_trellis, 118 avctx->trellis); 119 avctx->trellis = new_trellis; 120 } 121 } 122 123 return 0; 124error: 125 g722_encode_close(avctx); 126 return ret; 127} 128 129static const int16_t low_quant[33] = { 130 35, 72, 110, 150, 190, 233, 276, 323, 131 370, 422, 473, 530, 587, 650, 714, 786, 132 858, 940, 1023, 1121, 1219, 1339, 1458, 1612, 133 1765, 1980, 2195, 2557, 2919 134}; 135 136static inline void filter_samples(G722Context *c, const int16_t *samples, 137 int *xlow, int *xhigh) 138{ 139 int xout1, xout2; 140 c->prev_samples[c->prev_samples_pos++] = samples[0]; 141 c->prev_samples[c->prev_samples_pos++] = samples[1]; 142 ff_g722_apply_qmf(c->prev_samples + c->prev_samples_pos - 24, &xout1, &xout2); 143 *xlow = xout1 + xout2 >> 14; 144 *xhigh = xout1 - xout2 >> 14; 145 if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) { 146 memmove(c->prev_samples, 147 c->prev_samples + c->prev_samples_pos - 22, 148 22 * sizeof(c->prev_samples[0])); 149 c->prev_samples_pos = 22; 150 } 151} 152 153static inline int encode_high(const struct G722Band *state, int xhigh) 154{ 155 int diff = av_clip_int16(xhigh - state->s_predictor); 156 int pred = 141 * state->scale_factor >> 8; 157 /* = diff >= 0 ? (diff < pred) + 2 : diff >= -pred */ 158 return ((diff ^ (diff >> (sizeof(diff)*8-1))) < pred) + 2*(diff >= 0); 159} 160 161static inline int encode_low(const struct G722Band* state, int xlow) 162{ 163 int diff = av_clip_int16(xlow - state->s_predictor); 164 /* = diff >= 0 ? diff : -(diff + 1) */ 165 int limit = diff ^ (diff >> (sizeof(diff)*8-1)); 166 int i = 0; 167 limit = limit + 1 << 10; 168 if (limit > low_quant[8] * state->scale_factor) 169 i = 9; 170 while (i < 29 && limit > low_quant[i] * state->scale_factor) 171 i++; 172 return (diff < 0 ? (i < 2 ? 63 : 33) : 61) - i; 173} 174 175static void g722_encode_trellis(G722Context *c, int trellis, 176 uint8_t *dst, int nb_samples, 177 const int16_t *samples) 178{ 179 int i, j, k; 180 int frontier = 1 << trellis; 181 struct TrellisNode **nodes[2]; 182 struct TrellisNode **nodes_next[2]; 183 int pathn[2] = {0, 0}, froze = -1; 184 struct TrellisPath *p[2]; 185 186 for (i = 0; i < 2; i++) { 187 nodes[i] = c->nodep_buf[i]; 188 nodes_next[i] = c->nodep_buf[i] + frontier; 189 memset(c->nodep_buf[i], 0, 2 * frontier * sizeof(*c->nodep_buf[i])); 190 nodes[i][0] = c->node_buf[i] + frontier; 191 nodes[i][0]->ssd = 0; 192 nodes[i][0]->path = 0; 193 nodes[i][0]->state = c->band[i]; 194 } 195 196 for (i = 0; i < nb_samples >> 1; i++) { 197 int xlow, xhigh; 198 struct TrellisNode *next[2]; 199 int heap_pos[2] = {0, 0}; 200 201 for (j = 0; j < 2; j++) { 202 next[j] = c->node_buf[j] + frontier*(i & 1); 203 memset(nodes_next[j], 0, frontier * sizeof(**nodes_next)); 204 } 205 206 filter_samples(c, &samples[2*i], &xlow, &xhigh); 207 208 for (j = 0; j < frontier && nodes[0][j]; j++) { 209 /* Only k >> 2 affects the future adaptive state, therefore testing 210 * small steps that don't change k >> 2 is useless, the original 211 * value from encode_low is better than them. Since we step k 212 * in steps of 4, make sure range is a multiple of 4, so that 213 * we don't miss the original value from encode_low. */ 214 int range = j < frontier/2 ? 4 : 0; 215 struct TrellisNode *cur_node = nodes[0][j]; 216 217 int ilow = encode_low(&cur_node->state, xlow); 218 219 for (k = ilow - range; k <= ilow + range && k <= 63; k += 4) { 220 int decoded, dec_diff, pos; 221 uint32_t ssd; 222 struct TrellisNode* node; 223 224 if (k < 0) 225 continue; 226 227 decoded = av_clip((cur_node->state.scale_factor * 228 ff_g722_low_inv_quant6[k] >> 10) 229 + cur_node->state.s_predictor, -16384, 16383); 230 dec_diff = xlow - decoded; 231 232#define STORE_NODE(index, UPDATE, VALUE)\ 233 ssd = cur_node->ssd + dec_diff*dec_diff;\ 234 /* Check for wraparound. Using 64 bit ssd counters would \ 235 * be simpler, but is slower on x86 32 bit. */\ 236 if (ssd < cur_node->ssd)\ 237 continue;\ 238 if (heap_pos[index] < frontier) {\ 239 pos = heap_pos[index]++;\ 240 av_assert2(pathn[index] < FREEZE_INTERVAL * frontier);\ 241 node = nodes_next[index][pos] = next[index]++;\ 242 node->path = pathn[index]++;\ 243 } else {\ 244 /* Try to replace one of the leaf nodes with the new \ 245 * one, but not always testing the same leaf position */\ 246 pos = (frontier>>1) + (heap_pos[index] & ((frontier>>1) - 1));\ 247 if (ssd >= nodes_next[index][pos]->ssd)\ 248 continue;\ 249 heap_pos[index]++;\ 250 node = nodes_next[index][pos];\ 251 }\ 252 node->ssd = ssd;\ 253 node->state = cur_node->state;\ 254 UPDATE;\ 255 c->paths[index][node->path].value = VALUE;\ 256 c->paths[index][node->path].prev = cur_node->path;\ 257 /* Sift the newly inserted node up in the heap to restore \ 258 * the heap property */\ 259 while (pos > 0) {\ 260 int parent = (pos - 1) >> 1;\ 261 if (nodes_next[index][parent]->ssd <= ssd)\ 262 break;\ 263 FFSWAP(struct TrellisNode*, nodes_next[index][parent],\ 264 nodes_next[index][pos]);\ 265 pos = parent;\ 266 } 267 STORE_NODE(0, ff_g722_update_low_predictor(&node->state, k >> 2), k); 268 } 269 } 270 271 for (j = 0; j < frontier && nodes[1][j]; j++) { 272 int ihigh; 273 struct TrellisNode *cur_node = nodes[1][j]; 274 275 /* We don't try to get any initial guess for ihigh via 276 * encode_high - since there's only 4 possible values, test 277 * them all. Testing all of these gives a much, much larger 278 * gain than testing a larger range around ilow. */ 279 for (ihigh = 0; ihigh < 4; ihigh++) { 280 int dhigh, decoded, dec_diff, pos; 281 uint32_t ssd; 282 struct TrellisNode* node; 283 284 dhigh = cur_node->state.scale_factor * 285 ff_g722_high_inv_quant[ihigh] >> 10; 286 decoded = av_clip(dhigh + cur_node->state.s_predictor, 287 -16384, 16383); 288 dec_diff = xhigh - decoded; 289 290 STORE_NODE(1, ff_g722_update_high_predictor(&node->state, dhigh, ihigh), ihigh); 291 } 292 } 293 294 for (j = 0; j < 2; j++) { 295 FFSWAP(struct TrellisNode**, nodes[j], nodes_next[j]); 296 297 if (nodes[j][0]->ssd > (1 << 16)) { 298 for (k = 1; k < frontier && nodes[j][k]; k++) 299 nodes[j][k]->ssd -= nodes[j][0]->ssd; 300 nodes[j][0]->ssd = 0; 301 } 302 } 303 304 if (i == froze + FREEZE_INTERVAL) { 305 p[0] = &c->paths[0][nodes[0][0]->path]; 306 p[1] = &c->paths[1][nodes[1][0]->path]; 307 for (j = i; j > froze; j--) { 308 dst[j] = p[1]->value << 6 | p[0]->value; 309 p[0] = &c->paths[0][p[0]->prev]; 310 p[1] = &c->paths[1][p[1]->prev]; 311 } 312 froze = i; 313 pathn[0] = pathn[1] = 0; 314 memset(nodes[0] + 1, 0, (frontier - 1)*sizeof(**nodes)); 315 memset(nodes[1] + 1, 0, (frontier - 1)*sizeof(**nodes)); 316 } 317 } 318 319 p[0] = &c->paths[0][nodes[0][0]->path]; 320 p[1] = &c->paths[1][nodes[1][0]->path]; 321 for (j = i; j > froze; j--) { 322 dst[j] = p[1]->value << 6 | p[0]->value; 323 p[0] = &c->paths[0][p[0]->prev]; 324 p[1] = &c->paths[1][p[1]->prev]; 325 } 326 c->band[0] = nodes[0][0]->state; 327 c->band[1] = nodes[1][0]->state; 328} 329 330static av_always_inline void encode_byte(G722Context *c, uint8_t *dst, 331 const int16_t *samples) 332{ 333 int xlow, xhigh, ilow, ihigh; 334 filter_samples(c, samples, &xlow, &xhigh); 335 ihigh = encode_high(&c->band[1], xhigh); 336 ilow = encode_low (&c->band[0], xlow); 337 ff_g722_update_high_predictor(&c->band[1], c->band[1].scale_factor * 338 ff_g722_high_inv_quant[ihigh] >> 10, ihigh); 339 ff_g722_update_low_predictor(&c->band[0], ilow >> 2); 340 *dst = ihigh << 6 | ilow; 341} 342 343static void g722_encode_no_trellis(G722Context *c, 344 uint8_t *dst, int nb_samples, 345 const int16_t *samples) 346{ 347 int i; 348 for (i = 0; i < nb_samples; i += 2) 349 encode_byte(c, dst++, &samples[i]); 350} 351 352static int g722_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, 353 const AVFrame *frame, int *got_packet_ptr) 354{ 355 G722Context *c = avctx->priv_data; 356 const int16_t *samples = (const int16_t *)frame->data[0]; 357 int nb_samples, out_size, ret; 358 359 out_size = (frame->nb_samples + 1) / 2; 360 if ((ret = ff_alloc_packet2(avctx, avpkt, out_size)) < 0) 361 return ret; 362 363 nb_samples = frame->nb_samples - (frame->nb_samples & 1); 364 365 if (avctx->trellis) 366 g722_encode_trellis(c, avctx->trellis, avpkt->data, nb_samples, samples); 367 else 368 g722_encode_no_trellis(c, avpkt->data, nb_samples, samples); 369 370 /* handle last frame with odd frame_size */ 371 if (nb_samples < frame->nb_samples) { 372 int16_t last_samples[2] = { samples[nb_samples], samples[nb_samples] }; 373 encode_byte(c, &avpkt->data[nb_samples >> 1], last_samples); 374 } 375 376 if (frame->pts != AV_NOPTS_VALUE) 377 avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->delay); 378 *got_packet_ptr = 1; 379 return 0; 380} 381 382AVCodec ff_adpcm_g722_encoder = { 383 .name = "g722", 384 .long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"), 385 .type = AVMEDIA_TYPE_AUDIO, 386 .id = AV_CODEC_ID_ADPCM_G722, 387 .priv_data_size = sizeof(G722Context), 388 .init = g722_encode_init, 389 .close = g722_encode_close, 390 .encode2 = g722_encode_frame, 391 .capabilities = CODEC_CAP_SMALL_LAST_FRAME, 392 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16, 393 AV_SAMPLE_FMT_NONE }, 394}; 395