/*
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** Copyright 2011, The Android Open-Source Project
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**
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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**
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** http://www.apache.org/licenses/LICENSE-2.0
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**
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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*/
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//#define LOG_NDEBUG 0
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#define LOG_TAG "echo_reference"
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#include <errno.h>
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#include <inttypes.h>
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#include <pthread.h>
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#include <stdlib.h>
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#include <log/log.h>
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#include <system/audio.h>
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#include <audio_utils/resampler.h>
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#include <audio_utils/echo_reference.h>
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// echo reference state: bit field indicating if read, write or both are active.
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enum state {
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ECHOREF_IDLE = 0x00, // idle
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ECHOREF_READING = 0x01, // reading is active
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ECHOREF_WRITING = 0x02 // writing is active
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};
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struct echo_reference {
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struct echo_reference_itfe itfe;
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int status; // init status
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uint32_t state; // active state: reading, writing or both
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audio_format_t rd_format; // read sample format
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uint32_t rd_channel_count; // read number of channels
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uint32_t rd_sampling_rate; // read sampling rate in Hz
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size_t rd_frame_size; // read frame size (bytes per sample)
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audio_format_t wr_format; // write sample format
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uint32_t wr_channel_count; // write number of channels
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uint32_t wr_sampling_rate; // write sampling rate in Hz
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size_t wr_frame_size; // write frame size (bytes per sample)
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void *buffer; // main buffer
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size_t buf_size; // main buffer size in frames
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size_t frames_in; // number of frames in main buffer
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void *wr_buf; // buffer for input conversions
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size_t wr_buf_size; // size of conversion buffer in frames
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size_t wr_frames_in; // number of frames in conversion buffer
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size_t wr_curr_frame_size; // number of frames given to current write() function
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void *wr_src_buf; // resampler input buf (either wr_buf or buffer used by write())
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struct timespec wr_render_time; // latest render time indicated by write()
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// default ALSA gettimeofday() format
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int32_t playback_delay; // playback buffer delay indicated by last write()
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int16_t prev_delta_sign; // sign of previous delay difference:
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// 1: positive, -1: negative, 0: unknown
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uint16_t delta_count; // number of consecutive delay differences with same sign
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pthread_mutex_t lock; // mutex protecting read/write concurrency
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pthread_cond_t cond; // condition signaled when data is ready to read
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struct resampler_itfe *resampler; // input resampler
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struct resampler_buffer_provider provider; // resampler buffer provider
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};
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int echo_reference_get_next_buffer(struct resampler_buffer_provider *buffer_provider,
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struct resampler_buffer* buffer)
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{
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struct echo_reference *er;
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if (buffer_provider == NULL) {
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return -EINVAL;
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}
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er = (struct echo_reference *)((char *)buffer_provider -
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offsetof(struct echo_reference, provider));
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if (er->wr_src_buf == NULL || er->wr_frames_in == 0) {
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buffer->raw = NULL;
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buffer->frame_count = 0;
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return -ENODATA;
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}
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buffer->frame_count = (buffer->frame_count > er->wr_frames_in) ?
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er->wr_frames_in : buffer->frame_count;
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// this is er->rd_channel_count here as we resample after stereo to mono conversion if any
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buffer->i16 = (int16_t *)er->wr_src_buf + (er->wr_curr_frame_size - er->wr_frames_in) *
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er->rd_channel_count;
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return 0;
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}
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void echo_reference_release_buffer(struct resampler_buffer_provider *buffer_provider,
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struct resampler_buffer* buffer)
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{
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struct echo_reference *er;
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if (buffer_provider == NULL) {
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return;
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}
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er = (struct echo_reference *)((char *)buffer_provider -
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offsetof(struct echo_reference, provider));
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er->wr_frames_in -= buffer->frame_count;
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}
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static void echo_reference_reset_l(struct echo_reference *er)
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{
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ALOGV("echo_reference_reset_l()");
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free(er->buffer);
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er->buffer = NULL;
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er->buf_size = 0;
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er->frames_in = 0;
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free(er->wr_buf);
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er->wr_buf = NULL;
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er->wr_buf_size = 0;
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er->wr_render_time.tv_sec = 0;
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er->wr_render_time.tv_nsec = 0;
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er->delta_count = 0;
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er->prev_delta_sign = 0;
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}
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/* additional space in resampler buffer allowing for extra samples to be returned
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* by speex resampler when sample rates ratio is not an integer.
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*/
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#define RESAMPLER_HEADROOM_SAMPLES 10
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static int echo_reference_write(struct echo_reference_itfe *echo_reference,
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struct echo_reference_buffer *buffer)
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{
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struct echo_reference *er = (struct echo_reference *)echo_reference;
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int status = 0;
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if (er == NULL) {
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return -EINVAL;
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}
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pthread_mutex_lock(&er->lock);
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if (buffer == NULL) {
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ALOGV("echo_reference_write() stop write");
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er->state &= ~ECHOREF_WRITING;
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echo_reference_reset_l(er);
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goto exit;
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}
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ALOGV("echo_reference_write() START trying to write %zu frames", buffer->frame_count);
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ALOGV("echo_reference_write() playbackTimestamp:[%d].[%d], er->playback_delay:[%" PRId32 "]",
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(int)buffer->time_stamp.tv_sec,
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(int)buffer->time_stamp.tv_nsec, er->playback_delay);
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//ALOGV("echo_reference_write() %d frames", buffer->frame_count);
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// discard writes until a valid time stamp is provided.
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if ((buffer->time_stamp.tv_sec == 0) && (buffer->time_stamp.tv_nsec == 0) &&
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(er->wr_render_time.tv_sec == 0) && (er->wr_render_time.tv_nsec == 0)) {
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goto exit;
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}
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if ((er->state & ECHOREF_WRITING) == 0) {
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ALOGV("echo_reference_write() start write");
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if (er->resampler != NULL) {
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er->resampler->reset(er->resampler);
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}
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er->state |= ECHOREF_WRITING;
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}
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if ((er->state & ECHOREF_READING) == 0) {
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goto exit;
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}
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er->wr_render_time.tv_sec = buffer->time_stamp.tv_sec;
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er->wr_render_time.tv_nsec = buffer->time_stamp.tv_nsec;
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er->playback_delay = buffer->delay_ns;
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// this will be used in the get_next_buffer, to support variable input buffer sizes
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er->wr_curr_frame_size = buffer->frame_count;
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void *srcBuf;
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size_t inFrames;
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// do stereo to mono and down sampling if necessary
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if (er->rd_channel_count != er->wr_channel_count ||
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er->rd_sampling_rate != er->wr_sampling_rate) {
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size_t wrBufSize = buffer->frame_count;
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inFrames = buffer->frame_count;
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if (er->rd_sampling_rate != er->wr_sampling_rate) {
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inFrames = (buffer->frame_count * er->rd_sampling_rate) / er->wr_sampling_rate +
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RESAMPLER_HEADROOM_SAMPLES;
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// wr_buf is not only used as resampler output but also for stereo to mono conversion
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// output so buffer size is driven by both write and read sample rates
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if (inFrames > wrBufSize) {
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wrBufSize = inFrames;
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}
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}
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if (er->wr_buf_size < wrBufSize) {
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ALOGV("echo_reference_write() increasing write buffer size from %zu to %zu",
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er->wr_buf_size, wrBufSize);
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er->wr_buf_size = wrBufSize;
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er->wr_buf = realloc(er->wr_buf, er->wr_buf_size * er->rd_frame_size);
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}
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if (er->rd_channel_count != er->wr_channel_count) {
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// must be stereo to mono
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int16_t *src16 = (int16_t *)buffer->raw;
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int16_t *dst16 = (int16_t *)er->wr_buf;
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size_t frames = buffer->frame_count;
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while (frames--) {
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*dst16++ = (int16_t)(((int32_t)*src16 + (int32_t)*(src16 + 1)) >> 1);
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src16 += 2;
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}
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}
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if (er->wr_sampling_rate != er->rd_sampling_rate) {
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if (er->resampler == NULL) {
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int rc;
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ALOGV("echo_reference_write() new ReSampler(%d, %d)",
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er->wr_sampling_rate, er->rd_sampling_rate);
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er->provider.get_next_buffer = echo_reference_get_next_buffer;
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er->provider.release_buffer = echo_reference_release_buffer;
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rc = create_resampler(er->wr_sampling_rate,
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er->rd_sampling_rate,
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er->rd_channel_count,
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RESAMPLER_QUALITY_DEFAULT,
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&er->provider,
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&er->resampler);
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if (rc != 0) {
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er->resampler = NULL;
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ALOGV("echo_reference_write() failure to create resampler %d", rc);
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status = -ENODEV;
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goto exit;
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}
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}
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// er->wr_src_buf and er->wr_frames_in are used by getNexBuffer() called by the
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// resampler to get new frames
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if (er->rd_channel_count != er->wr_channel_count) {
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er->wr_src_buf = er->wr_buf;
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} else {
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er->wr_src_buf = buffer->raw;
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}
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er->wr_frames_in = buffer->frame_count;
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// inFrames is always more than we need here to get frames remaining from previous runs
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// inFrames is updated by resample() with the number of frames produced
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ALOGV("echo_reference_write() ReSampling(%d, %d)",
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er->wr_sampling_rate, er->rd_sampling_rate);
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er->resampler->resample_from_provider(er->resampler,
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(int16_t *)er->wr_buf, &inFrames);
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ALOGV_IF(er->wr_frames_in != 0,
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"echo_reference_write() er->wr_frames_in not 0 (%d) after resampler",
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er->wr_frames_in);
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}
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srcBuf = er->wr_buf;
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} else {
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inFrames = buffer->frame_count;
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srcBuf = buffer->raw;
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}
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if (er->frames_in + inFrames > er->buf_size) {
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ALOGV("echo_reference_write() increasing buffer size from %zu to %zu",
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er->buf_size, er->frames_in + inFrames);
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er->buf_size = er->frames_in + inFrames;
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er->buffer = realloc(er->buffer, er->buf_size * er->rd_frame_size);
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}
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memcpy((char *)er->buffer + er->frames_in * er->rd_frame_size,
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srcBuf,
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inFrames * er->rd_frame_size);
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er->frames_in += inFrames;
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ALOGV("echo_reference_write() frames written:[%zu], frames total:[%zu] buffer size:[%zu]\n"
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" er->wr_render_time:[%d].[%d], er->playback_delay:[%" PRId32 "]",
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inFrames, er->frames_in, er->buf_size,
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(int)er->wr_render_time.tv_sec, (int)er->wr_render_time.tv_nsec, er->playback_delay);
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pthread_cond_signal(&er->cond);
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exit:
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pthread_mutex_unlock(&er->lock);
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ALOGV("echo_reference_write() END");
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return status;
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}
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// delay jump threshold to update ref buffer: 6 samples at 8kHz in nsecs
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#define MIN_DELAY_DELTA_NS (375000*2)
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// number of consecutive delta with same sign between expected and actual delay before adjusting
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// the buffer
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#define MIN_DELTA_NUM 4
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static int echo_reference_read(struct echo_reference_itfe *echo_reference,
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struct echo_reference_buffer *buffer)
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{
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struct echo_reference *er = (struct echo_reference *)echo_reference;
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if (er == NULL) {
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return -EINVAL;
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}
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pthread_mutex_lock(&er->lock);
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if (buffer == NULL) {
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ALOGV("echo_reference_read() stop read");
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er->state &= ~ECHOREF_READING;
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goto exit;
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}
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ALOGV("echo_reference_read() START, delayCapture:[%" PRId32 "], "
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"er->frames_in:[%zu],buffer->frame_count:[%zu]",
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buffer->delay_ns, er->frames_in, buffer->frame_count);
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if ((er->state & ECHOREF_READING) == 0) {
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ALOGV("echo_reference_read() start read");
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echo_reference_reset_l(er);
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er->state |= ECHOREF_READING;
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}
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if ((er->state & ECHOREF_WRITING) == 0) {
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memset(buffer->raw, 0, er->rd_frame_size * buffer->frame_count);
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buffer->delay_ns = 0;
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goto exit;
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}
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// ALOGV("echo_reference_read() %d frames", buffer->frame_count);
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// allow some time for new frames to arrive if not enough frames are ready for read
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if (er->frames_in < buffer->frame_count) {
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uint32_t timeoutMs = (uint32_t)((1000 * buffer->frame_count) / er->rd_sampling_rate / 2);
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struct timespec ts = {0, 0};
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clock_gettime(CLOCK_REALTIME, &ts);
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ts.tv_sec += timeoutMs/1000;
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ts.tv_nsec += (timeoutMs%1000) * 1000000;
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if (ts.tv_nsec >= 1000000000) {
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ts.tv_nsec -= 1000000000;
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ts.tv_sec += 1;
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}
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pthread_cond_timedwait(&er->cond, &er->lock, &ts);
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ALOGV_IF((er->frames_in < buffer->frame_count),
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"echo_reference_read() waited %d ms but still not enough frames"\
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" er->frames_in: %d, buffer->frame_count = %d",
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timeoutMs, er->frames_in, buffer->frame_count);
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}
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int64_t timeDiff;
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struct timespec tmp;
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if ((er->wr_render_time.tv_sec == 0 && er->wr_render_time.tv_nsec == 0) ||
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(buffer->time_stamp.tv_sec == 0 && buffer->time_stamp.tv_nsec == 0)) {
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ALOGV("echo_reference_read(): NEW:timestamp is zero---------setting timeDiff = 0, "\
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"not updating delay this time");
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timeDiff = 0;
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} else {
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if (buffer->time_stamp.tv_nsec < er->wr_render_time.tv_nsec) {
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tmp.tv_sec = buffer->time_stamp.tv_sec - er->wr_render_time.tv_sec - 1;
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tmp.tv_nsec = 1000000000 + buffer->time_stamp.tv_nsec - er->wr_render_time.tv_nsec;
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} else {
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tmp.tv_sec = buffer->time_stamp.tv_sec - er->wr_render_time.tv_sec;
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tmp.tv_nsec = buffer->time_stamp.tv_nsec - er->wr_render_time.tv_nsec;
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}
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timeDiff = (((int64_t)tmp.tv_sec * 1000000000 + tmp.tv_nsec));
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int64_t expectedDelayNs = er->playback_delay + buffer->delay_ns - timeDiff;
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if (er->resampler != NULL) {
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// Resampler already compensates part of the delay
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int32_t rsmp_delay = er->resampler->delay_ns(er->resampler);
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expectedDelayNs -= rsmp_delay;
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}
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ALOGV("echo_reference_read(): expectedDelayNs[%" PRId64 "] = "
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"er->playback_delay[%" PRId32 "] + delayCapture[%" PRId32
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"] - timeDiff[%" PRId64 "]",
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expectedDelayNs, er->playback_delay, buffer->delay_ns, timeDiff);
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if (expectedDelayNs > 0) {
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int64_t delayNs = ((int64_t)er->frames_in * 1000000000) / er->rd_sampling_rate;
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int64_t deltaNs = delayNs - expectedDelayNs;
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ALOGV("echo_reference_read(): EchoPathDelayDeviation between reference and DMA [%"
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PRId64 "]", deltaNs);
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if (llabs(deltaNs) >= MIN_DELAY_DELTA_NS) {
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// smooth the variation and update the reference buffer only
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// if a deviation in the same direction is observed for more than MIN_DELTA_NUM
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// consecutive reads.
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int16_t delay_sign = (deltaNs >= 0) ? 1 : -1;
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if (delay_sign == er->prev_delta_sign) {
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er->delta_count++;
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} else {
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er->delta_count = 1;
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}
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er->prev_delta_sign = delay_sign;
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if (er->delta_count > MIN_DELTA_NUM) {
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size_t previousFrameIn = er->frames_in;
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er->frames_in = (size_t)((expectedDelayNs * er->rd_sampling_rate)/1000000000);
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int offset = er->frames_in - previousFrameIn;
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ALOGV("echo_reference_read(): deltaNs ENOUGH and %s: "
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"er->frames_in: %zu, previousFrameIn = %zu",
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delay_sign ? "positive" : "negative", er->frames_in, previousFrameIn);
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if (deltaNs < 0) {
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// Less data available in the reference buffer than expected
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if (er->frames_in > er->buf_size) {
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er->buf_size = er->frames_in;
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er->buffer = realloc(er->buffer, er->buf_size * er->rd_frame_size);
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ALOGV("echo_reference_read(): increasing buffer size to %zu",
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er->buf_size);
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}
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if (offset > 0) {
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memset((char *)er->buffer + previousFrameIn * er->rd_frame_size,
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0, offset * er->rd_frame_size);
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ALOGV("echo_reference_read(): pushing ref buffer by [%d]", offset);
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}
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} else {
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// More data available in the reference buffer than expected
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offset = -offset;
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if (offset > 0) {
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memcpy(er->buffer, (char *)er->buffer + (offset * er->rd_frame_size),
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er->frames_in * er->rd_frame_size);
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ALOGV("echo_reference_read(): shifting ref buffer by [%zu]",
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er->frames_in);
|
}
|
}
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}
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} else {
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er->delta_count = 0;
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er->prev_delta_sign = 0;
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ALOGV("echo_reference_read(): Constant EchoPathDelay - difference "
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"between reference and DMA %" PRId64, deltaNs);
|
}
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} else {
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ALOGV("echo_reference_read(): NEGATIVE expectedDelayNs[%" PRId64
|
"] = er->playback_delay[%" PRId32 "] + delayCapture[%" PRId32
|
"] - timeDiff[%" PRId64 "]",
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expectedDelayNs, er->playback_delay, buffer->delay_ns, timeDiff);
|
}
|
}
|
|
if (er->frames_in < buffer->frame_count) {
|
if (buffer->frame_count > er->buf_size) {
|
er->buf_size = buffer->frame_count;
|
er->buffer = realloc(er->buffer, er->buf_size * er->rd_frame_size);
|
ALOGV("echo_reference_read(): increasing buffer size to %zu", er->buf_size);
|
}
|
// filling up the reference buffer with 0s to match the expected delay.
|
memset((char *)er->buffer + er->frames_in * er->rd_frame_size,
|
0, (buffer->frame_count - er->frames_in) * er->rd_frame_size);
|
er->frames_in = buffer->frame_count;
|
}
|
|
memcpy(buffer->raw,
|
(char *)er->buffer,
|
buffer->frame_count * er->rd_frame_size);
|
|
er->frames_in -= buffer->frame_count;
|
memcpy(er->buffer,
|
(char *)er->buffer + buffer->frame_count * er->rd_frame_size,
|
er->frames_in * er->rd_frame_size);
|
|
// As the reference buffer is now time aligned to the microphone signal there is a zero delay
|
buffer->delay_ns = 0;
|
|
ALOGV("echo_reference_read() END %zu frames, total frames in %zu",
|
buffer->frame_count, er->frames_in);
|
|
pthread_cond_signal(&er->cond);
|
|
exit:
|
pthread_mutex_unlock(&er->lock);
|
return 0;
|
}
|
|
|
int create_echo_reference(audio_format_t rdFormat,
|
uint32_t rdChannelCount,
|
uint32_t rdSamplingRate,
|
audio_format_t wrFormat,
|
uint32_t wrChannelCount,
|
uint32_t wrSamplingRate,
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struct echo_reference_itfe **echo_reference)
|
{
|
struct echo_reference *er;
|
|
ALOGV("create_echo_reference()");
|
|
if (echo_reference == NULL) {
|
return -EINVAL;
|
}
|
|
*echo_reference = NULL;
|
|
if (rdFormat != AUDIO_FORMAT_PCM_16_BIT ||
|
rdFormat != wrFormat) {
|
ALOGW("create_echo_reference bad format rd %d, wr %d", rdFormat, wrFormat);
|
return -EINVAL;
|
}
|
if ((rdChannelCount != 1 && rdChannelCount != 2) ||
|
wrChannelCount != 2) {
|
ALOGW("create_echo_reference bad channel count rd %d, wr %d", rdChannelCount,
|
wrChannelCount);
|
return -EINVAL;
|
}
|
|
er = (struct echo_reference *)calloc(1, sizeof(struct echo_reference));
|
|
er->itfe.read = echo_reference_read;
|
er->itfe.write = echo_reference_write;
|
|
er->state = ECHOREF_IDLE;
|
er->rd_format = rdFormat;
|
er->rd_channel_count = rdChannelCount;
|
er->rd_sampling_rate = rdSamplingRate;
|
er->wr_format = wrFormat;
|
er->wr_channel_count = wrChannelCount;
|
er->wr_sampling_rate = wrSamplingRate;
|
er->rd_frame_size = audio_bytes_per_sample(rdFormat) * rdChannelCount;
|
er->wr_frame_size = audio_bytes_per_sample(wrFormat) * wrChannelCount;
|
*echo_reference = &er->itfe;
|
return 0;
|
}
|
|
void release_echo_reference(struct echo_reference_itfe *echo_reference) {
|
struct echo_reference *er = (struct echo_reference *)echo_reference;
|
|
if (er == NULL) {
|
return;
|
}
|
|
ALOGV("EchoReference dstor");
|
echo_reference_reset_l(er);
|
if (er->resampler != NULL) {
|
release_resampler(er->resampler);
|
}
|
free(er);
|
}
|
