1/* 2** Copyright 2011, The Android Open-Source Project 3** 4** Licensed under the Apache License, Version 2.0 (the "License"); 5** you may not use this file except in compliance with the License. 6** You may obtain a copy of the License at 7** 8** http://www.apache.org/licenses/LICENSE-2.0 9** 10** Unless required by applicable law or agreed to in writing, software 11** distributed under the License is distributed on an "AS IS" BASIS, 12** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13** See the License for the specific language governing permissions and 14** limitations under the License. 15*/ 16 17//#define LOG_NDEBUG 0 18#define LOG_TAG "echo_reference" 19 20#include <errno.h> 21#include <stdlib.h> 22#include <pthread.h> 23#include <cutils/log.h> 24#include <system/audio.h> 25#include <audio_utils/resampler.h> 26#include <audio_utils/echo_reference.h> 27 28// echo reference state: bit field indicating if read, write or both are active. 29enum state { 30 ECHOREF_IDLE = 0x00, // idle 31 ECHOREF_READING = 0x01, // reading is active 32 ECHOREF_WRITING = 0x02 // writing is active 33}; 34 35struct echo_reference { 36 struct echo_reference_itfe itfe; 37 int status; // init status 38 uint32_t state; // active state: reading, writing or both 39 audio_format_t rd_format; // read sample format 40 uint32_t rd_channel_count; // read number of channels 41 uint32_t rd_sampling_rate; // read sampling rate in Hz 42 size_t rd_frame_size; // read frame size (bytes per sample) 43 audio_format_t wr_format; // write sample format 44 uint32_t wr_channel_count; // write number of channels 45 uint32_t wr_sampling_rate; // write sampling rate in Hz 46 size_t wr_frame_size; // write frame size (bytes per sample) 47 void *buffer; // main buffer 48 size_t buf_size; // main buffer size in frames 49 size_t frames_in; // number of frames in main buffer 50 void *wr_buf; // buffer for input conversions 51 size_t wr_buf_size; // size of conversion buffer in frames 52 size_t wr_frames_in; // number of frames in conversion buffer 53 size_t wr_curr_frame_size; // number of frames given to current write() function 54 void *wr_src_buf; // resampler input buf (either wr_buf or buffer used by write()) 55 struct timespec wr_render_time; // latest render time indicated by write() 56 // default ALSA gettimeofday() format 57 int32_t playback_delay; // playback buffer delay indicated by last write() 58 int16_t prev_delta_sign; // sign of previous delay difference: 59 // 1: positive, -1: negative, 0: unknown 60 uint16_t delta_count; // number of consecutive delay differences with same sign 61 pthread_mutex_t lock; // mutex protecting read/write concurrency 62 pthread_cond_t cond; // condition signaled when data is ready to read 63 struct resampler_itfe *resampler; // input resampler 64 struct resampler_buffer_provider provider; // resampler buffer provider 65}; 66 67 68int echo_reference_get_next_buffer(struct resampler_buffer_provider *buffer_provider, 69 struct resampler_buffer* buffer) 70{ 71 struct echo_reference *er; 72 73 if (buffer_provider == NULL) { 74 return -EINVAL; 75 } 76 77 er = (struct echo_reference *)((char *)buffer_provider - 78 offsetof(struct echo_reference, provider)); 79 80 if (er->wr_src_buf == NULL || er->wr_frames_in == 0) { 81 buffer->raw = NULL; 82 buffer->frame_count = 0; 83 return -ENODATA; 84 } 85 86 buffer->frame_count = (buffer->frame_count > er->wr_frames_in) ? er->wr_frames_in : buffer->frame_count; 87 // this is er->rd_channel_count here as we resample after stereo to mono conversion if any 88 buffer->i16 = (int16_t *)er->wr_src_buf + (er->wr_curr_frame_size - er->wr_frames_in) * er->rd_channel_count; 89 90 return 0; 91} 92 93void echo_reference_release_buffer(struct resampler_buffer_provider *buffer_provider, 94 struct resampler_buffer* buffer) 95{ 96 struct echo_reference *er; 97 98 if (buffer_provider == NULL) { 99 return; 100 } 101 102 er = (struct echo_reference *)((char *)buffer_provider - 103 offsetof(struct echo_reference, provider)); 104 105 er->wr_frames_in -= buffer->frame_count; 106} 107 108static void echo_reference_reset_l(struct echo_reference *er) 109{ 110 ALOGV("echo_reference_reset_l()"); 111 free(er->buffer); 112 er->buffer = NULL; 113 er->buf_size = 0; 114 er->frames_in = 0; 115 free(er->wr_buf); 116 er->wr_buf = NULL; 117 er->wr_buf_size = 0; 118 er->wr_render_time.tv_sec = 0; 119 er->wr_render_time.tv_nsec = 0; 120 er->delta_count = 0; 121 er->prev_delta_sign = 0; 122} 123 124/* additional space in resampler buffer allowing for extra samples to be returned 125 * by speex resampler when sample rates ratio is not an integer. 126 */ 127#define RESAMPLER_HEADROOM_SAMPLES 10 128 129static int echo_reference_write(struct echo_reference_itfe *echo_reference, 130 struct echo_reference_buffer *buffer) 131{ 132 struct echo_reference *er = (struct echo_reference *)echo_reference; 133 int status = 0; 134 135 if (er == NULL) { 136 return -EINVAL; 137 } 138 139 pthread_mutex_lock(&er->lock); 140 141 if (buffer == NULL) { 142 ALOGV("echo_reference_write() stop write"); 143 er->state &= ~ECHOREF_WRITING; 144 echo_reference_reset_l(er); 145 goto exit; 146 } 147 148 ALOGV("echo_reference_write() START trying to write %d frames", buffer->frame_count); 149 ALOGV("echo_reference_write() playbackTimestamp:[%d].[%d], er->playback_delay:[%d]", 150 (int)buffer->time_stamp.tv_sec, 151 (int)buffer->time_stamp.tv_nsec, er->playback_delay); 152 153 //ALOGV("echo_reference_write() %d frames", buffer->frame_count); 154 // discard writes until a valid time stamp is provided. 155 156 if ((buffer->time_stamp.tv_sec == 0) && (buffer->time_stamp.tv_nsec == 0) && 157 (er->wr_render_time.tv_sec == 0) && (er->wr_render_time.tv_nsec == 0)) { 158 goto exit; 159 } 160 161 if ((er->state & ECHOREF_WRITING) == 0) { 162 ALOGV("echo_reference_write() start write"); 163 if (er->resampler != NULL) { 164 er->resampler->reset(er->resampler); 165 } 166 er->state |= ECHOREF_WRITING; 167 } 168 169 if ((er->state & ECHOREF_READING) == 0) { 170 goto exit; 171 } 172 173 er->wr_render_time.tv_sec = buffer->time_stamp.tv_sec; 174 er->wr_render_time.tv_nsec = buffer->time_stamp.tv_nsec; 175 176 er->playback_delay = buffer->delay_ns; 177 178 // this will be used in the get_next_buffer, to support variable input buffer sizes 179 er->wr_curr_frame_size = buffer->frame_count; 180 181 void *srcBuf; 182 size_t inFrames; 183 // do stereo to mono and down sampling if necessary 184 if (er->rd_channel_count != er->wr_channel_count || 185 er->rd_sampling_rate != er->wr_sampling_rate) { 186 size_t wrBufSize = buffer->frame_count; 187 188 inFrames = buffer->frame_count; 189 190 if (er->rd_sampling_rate != er->wr_sampling_rate) { 191 inFrames = (buffer->frame_count * er->rd_sampling_rate) / er->wr_sampling_rate + 192 RESAMPLER_HEADROOM_SAMPLES; 193 // wr_buf is not only used as resampler output but also for stereo to mono conversion 194 // output so buffer size is driven by both write and read sample rates 195 if (inFrames > wrBufSize) { 196 wrBufSize = inFrames; 197 } 198 } 199 200 if (er->wr_buf_size < wrBufSize) { 201 ALOGV("echo_reference_write() increasing write buffer size from %d to %d", 202 er->wr_buf_size, wrBufSize); 203 er->wr_buf_size = wrBufSize; 204 er->wr_buf = realloc(er->wr_buf, er->wr_buf_size * er->rd_frame_size); 205 } 206 207 if (er->rd_channel_count != er->wr_channel_count) { 208 // must be stereo to mono 209 int16_t *src16 = (int16_t *)buffer->raw; 210 int16_t *dst16 = (int16_t *)er->wr_buf; 211 size_t frames = buffer->frame_count; 212 while (frames--) { 213 *dst16++ = (int16_t)(((int32_t)*src16 + (int32_t)*(src16 + 1)) >> 1); 214 src16 += 2; 215 } 216 } 217 if (er->wr_sampling_rate != er->rd_sampling_rate) { 218 if (er->resampler == NULL) { 219 int rc; 220 ALOGV("echo_reference_write() new ReSampler(%d, %d)", 221 er->wr_sampling_rate, er->rd_sampling_rate); 222 er->provider.get_next_buffer = echo_reference_get_next_buffer; 223 er->provider.release_buffer = echo_reference_release_buffer; 224 rc = create_resampler(er->wr_sampling_rate, 225 er->rd_sampling_rate, 226 er->rd_channel_count, 227 RESAMPLER_QUALITY_DEFAULT, 228 &er->provider, 229 &er->resampler); 230 if (rc != 0) { 231 er->resampler = NULL; 232 ALOGV("echo_reference_write() failure to create resampler %d", rc); 233 status = -ENODEV; 234 goto exit; 235 } 236 } 237 // er->wr_src_buf and er->wr_frames_in are used by getNexBuffer() called by the resampler 238 // to get new frames 239 if (er->rd_channel_count != er->wr_channel_count) { 240 er->wr_src_buf = er->wr_buf; 241 } else { 242 er->wr_src_buf = buffer->raw; 243 } 244 er->wr_frames_in = buffer->frame_count; 245 // inFrames is always more than we need here to get frames remaining from previous runs 246 // inFrames is updated by resample() with the number of frames produced 247 ALOGV("echo_reference_write() ReSampling(%d, %d)", 248 er->wr_sampling_rate, er->rd_sampling_rate); 249 er->resampler->resample_from_provider(er->resampler, 250 (int16_t *)er->wr_buf, &inFrames); 251 ALOGV_IF(er->wr_frames_in != 0, 252 "echo_reference_write() er->wr_frames_in not 0 (%d) after resampler", 253 er->wr_frames_in); 254 } 255 srcBuf = er->wr_buf; 256 } else { 257 inFrames = buffer->frame_count; 258 srcBuf = buffer->raw; 259 } 260 261 if (er->frames_in + inFrames > er->buf_size) { 262 ALOGV("echo_reference_write() increasing buffer size from %d to %d", 263 er->buf_size, er->frames_in + inFrames); 264 er->buf_size = er->frames_in + inFrames; 265 er->buffer = realloc(er->buffer, er->buf_size * er->rd_frame_size); 266 } 267 memcpy((char *)er->buffer + er->frames_in * er->rd_frame_size, 268 srcBuf, 269 inFrames * er->rd_frame_size); 270 er->frames_in += inFrames; 271 272 ALOGV("echo_reference_write() frames written:[%d], frames total:[%d] buffer size:[%d]\n" 273 " er->wr_render_time:[%d].[%d], er->playback_delay:[%d]", 274 inFrames, er->frames_in, er->buf_size, 275 (int)er->wr_render_time.tv_sec, (int)er->wr_render_time.tv_nsec, er->playback_delay); 276 277 pthread_cond_signal(&er->cond); 278exit: 279 pthread_mutex_unlock(&er->lock); 280 ALOGV("echo_reference_write() END"); 281 return status; 282} 283 284// delay jump threshold to update ref buffer: 6 samples at 8kHz in nsecs 285#define MIN_DELAY_DELTA_NS (375000*2) 286// number of consecutive delta with same sign between expected and actual delay before adjusting 287// the buffer 288#define MIN_DELTA_NUM 4 289 290 291static int echo_reference_read(struct echo_reference_itfe *echo_reference, 292 struct echo_reference_buffer *buffer) 293{ 294 struct echo_reference *er = (struct echo_reference *)echo_reference; 295 296 if (er == NULL) { 297 return -EINVAL; 298 } 299 300 pthread_mutex_lock(&er->lock); 301 302 if (buffer == NULL) { 303 ALOGV("echo_reference_read() stop read"); 304 er->state &= ~ECHOREF_READING; 305 goto exit; 306 } 307 308 ALOGV("echo_reference_read() START, delayCapture:[%d], " 309 "er->frames_in:[%d],buffer->frame_count:[%d]", 310 buffer->delay_ns, er->frames_in, buffer->frame_count); 311 312 if ((er->state & ECHOREF_READING) == 0) { 313 ALOGV("echo_reference_read() start read"); 314 echo_reference_reset_l(er); 315 er->state |= ECHOREF_READING; 316 } 317 318 if ((er->state & ECHOREF_WRITING) == 0) { 319 memset(buffer->raw, 0, er->rd_frame_size * buffer->frame_count); 320 buffer->delay_ns = 0; 321 goto exit; 322 } 323 324// ALOGV("echo_reference_read() %d frames", buffer->frame_count); 325 326 // allow some time for new frames to arrive if not enough frames are ready for read 327 if (er->frames_in < buffer->frame_count) { 328 uint32_t timeoutMs = (uint32_t)((1000 * buffer->frame_count) / er->rd_sampling_rate / 2); 329 struct timespec ts; 330 331 ts.tv_sec = timeoutMs/1000; 332 ts.tv_nsec = timeoutMs%1000; 333 pthread_cond_timedwait_relative_np(&er->cond, &er->lock, &ts); 334 335 ALOGV_IF((er->frames_in < buffer->frame_count), 336 "echo_reference_read() waited %d ms but still not enough frames"\ 337 " er->frames_in: %d, buffer->frame_count = %d", 338 timeoutMs, er->frames_in, buffer->frame_count); 339 } 340 341 int64_t timeDiff; 342 struct timespec tmp; 343 344 if ((er->wr_render_time.tv_sec == 0 && er->wr_render_time.tv_nsec == 0) || 345 (buffer->time_stamp.tv_sec == 0 && buffer->time_stamp.tv_nsec == 0)) { 346 ALOGV("echo_reference_read(): NEW:timestamp is zero---------setting timeDiff = 0, "\ 347 "not updating delay this time"); 348 timeDiff = 0; 349 } else { 350 if (buffer->time_stamp.tv_nsec < er->wr_render_time.tv_nsec) { 351 tmp.tv_sec = buffer->time_stamp.tv_sec - er->wr_render_time.tv_sec - 1; 352 tmp.tv_nsec = 1000000000 + buffer->time_stamp.tv_nsec - er->wr_render_time.tv_nsec; 353 } else { 354 tmp.tv_sec = buffer->time_stamp.tv_sec - er->wr_render_time.tv_sec; 355 tmp.tv_nsec = buffer->time_stamp.tv_nsec - er->wr_render_time.tv_nsec; 356 } 357 timeDiff = (((int64_t)tmp.tv_sec * 1000000000 + tmp.tv_nsec)); 358 359 int64_t expectedDelayNs = er->playback_delay + buffer->delay_ns - timeDiff; 360 361 if (er->resampler != NULL) { 362 // Resampler already compensates part of the delay 363 int32_t rsmp_delay = er->resampler->delay_ns(er->resampler); 364 expectedDelayNs -= rsmp_delay; 365 } 366 367 ALOGV("echo_reference_read(): expectedDelayNs[%lld] = " 368 "er->playback_delay[%d] + delayCapture[%d] - timeDiff[%lld]", 369 expectedDelayNs, er->playback_delay, buffer->delay_ns, timeDiff); 370 371 if (expectedDelayNs > 0) { 372 int64_t delayNs = ((int64_t)er->frames_in * 1000000000) / er->rd_sampling_rate; 373 374 int64_t deltaNs = delayNs - expectedDelayNs; 375 376 ALOGV("echo_reference_read(): EchoPathDelayDeviation between reference and DMA [%lld]", deltaNs); 377 if (abs(deltaNs) >= MIN_DELAY_DELTA_NS) { 378 // smooth the variation and update the reference buffer only 379 // if a deviation in the same direction is observed for more than MIN_DELTA_NUM 380 // consecutive reads. 381 int16_t delay_sign = (deltaNs >= 0) ? 1 : -1; 382 if (delay_sign == er->prev_delta_sign) { 383 er->delta_count++; 384 } else { 385 er->delta_count = 1; 386 } 387 er->prev_delta_sign = delay_sign; 388 389 if (er->delta_count > MIN_DELTA_NUM) { 390 size_t previousFrameIn = er->frames_in; 391 er->frames_in = (size_t)((expectedDelayNs * er->rd_sampling_rate)/1000000000); 392 int offset = er->frames_in - previousFrameIn; 393 394 ALOGV("echo_reference_read(): deltaNs ENOUGH and %s: " 395 "er->frames_in: %d, previousFrameIn = %d", 396 delay_sign ? "positive" : "negative", er->frames_in, previousFrameIn); 397 398 if (deltaNs < 0) { 399 // Less data available in the reference buffer than expected 400 if (er->frames_in > er->buf_size) { 401 er->buf_size = er->frames_in; 402 er->buffer = realloc(er->buffer, er->buf_size * er->rd_frame_size); 403 ALOGV("echo_reference_read(): increasing buffer size to %d", 404 er->buf_size); 405 } 406 407 if (offset > 0) { 408 memset((char *)er->buffer + previousFrameIn * er->rd_frame_size, 409 0, offset * er->rd_frame_size); 410 ALOGV("echo_reference_read(): pushing ref buffer by [%d]", offset); 411 } 412 } else { 413 // More data available in the reference buffer than expected 414 offset = -offset; 415 if (offset > 0) { 416 memcpy(er->buffer, (char *)er->buffer + (offset * er->rd_frame_size), 417 er->frames_in * er->rd_frame_size); 418 ALOGV("echo_reference_read(): shifting ref buffer by [%d]", 419 er->frames_in); 420 } 421 } 422 } 423 } else { 424 er->delta_count = 0; 425 er->prev_delta_sign = 0; 426 ALOGV("echo_reference_read(): Constant EchoPathDelay - difference " 427 "between reference and DMA %lld", deltaNs); 428 } 429 } else { 430 ALOGV("echo_reference_read(): NEGATIVE expectedDelayNs[%lld] = "\ 431 "er->playback_delay[%d] + delayCapture[%d] - timeDiff[%lld]", 432 expectedDelayNs, er->playback_delay, buffer->delay_ns, timeDiff); 433 } 434 } 435 436 if (er->frames_in < buffer->frame_count) { 437 if (buffer->frame_count > er->buf_size) { 438 er->buf_size = buffer->frame_count; 439 er->buffer = realloc(er->buffer, er->buf_size * er->rd_frame_size); 440 ALOGV("echo_reference_read(): increasing buffer size to %d", er->buf_size); 441 } 442 // filling up the reference buffer with 0s to match the expected delay. 443 memset((char *)er->buffer + er->frames_in * er->rd_frame_size, 444 0, (buffer->frame_count - er->frames_in) * er->rd_frame_size); 445 er->frames_in = buffer->frame_count; 446 } 447 448 memcpy(buffer->raw, 449 (char *)er->buffer, 450 buffer->frame_count * er->rd_frame_size); 451 452 er->frames_in -= buffer->frame_count; 453 memcpy(er->buffer, 454 (char *)er->buffer + buffer->frame_count * er->rd_frame_size, 455 er->frames_in * er->rd_frame_size); 456 457 // As the reference buffer is now time aligned to the microphone signal there is a zero delay 458 buffer->delay_ns = 0; 459 460 ALOGV("echo_reference_read() END %d frames, total frames in %d", 461 buffer->frame_count, er->frames_in); 462 463 pthread_cond_signal(&er->cond); 464 465exit: 466 pthread_mutex_unlock(&er->lock); 467 return 0; 468} 469 470 471int create_echo_reference(audio_format_t rdFormat, 472 uint32_t rdChannelCount, 473 uint32_t rdSamplingRate, 474 audio_format_t wrFormat, 475 uint32_t wrChannelCount, 476 uint32_t wrSamplingRate, 477 struct echo_reference_itfe **echo_reference) 478{ 479 struct echo_reference *er; 480 481 ALOGV("create_echo_reference()"); 482 483 if (echo_reference == NULL) { 484 return -EINVAL; 485 } 486 487 *echo_reference = NULL; 488 489 if (rdFormat != AUDIO_FORMAT_PCM_16_BIT || 490 rdFormat != wrFormat) { 491 ALOGW("create_echo_reference bad format rd %d, wr %d", rdFormat, wrFormat); 492 return -EINVAL; 493 } 494 if ((rdChannelCount != 1 && rdChannelCount != 2) || 495 wrChannelCount != 2) { 496 ALOGW("create_echo_reference bad channel count rd %d, wr %d", rdChannelCount, wrChannelCount); 497 return -EINVAL; 498 } 499 500 er = (struct echo_reference *)calloc(1, sizeof(struct echo_reference)); 501 502 er->itfe.read = echo_reference_read; 503 er->itfe.write = echo_reference_write; 504 505 er->state = ECHOREF_IDLE; 506 er->rd_format = rdFormat; 507 er->rd_channel_count = rdChannelCount; 508 er->rd_sampling_rate = rdSamplingRate; 509 er->wr_format = wrFormat; 510 er->wr_channel_count = wrChannelCount; 511 er->wr_sampling_rate = wrSamplingRate; 512 er->rd_frame_size = audio_bytes_per_sample(rdFormat) * rdChannelCount; 513 er->wr_frame_size = audio_bytes_per_sample(wrFormat) * wrChannelCount; 514 *echo_reference = &er->itfe; 515 return 0; 516} 517 518void release_echo_reference(struct echo_reference_itfe *echo_reference) { 519 struct echo_reference *er = (struct echo_reference *)echo_reference; 520 521 if (er == NULL) { 522 return; 523 } 524 525 ALOGV("EchoReference dstor"); 526 echo_reference_reset_l(er); 527 if (er->resampler != NULL) { 528 release_resampler(er->resampler); 529 } 530 free(er); 531} 532 533