myvtm/Other/libaudioframework/audioaec.c

#include "precompile.h"
#include "audioaec.h"
#include "audioengine.h"

#include <speex/speex_echo.h>


static apr_status_t read_frame(void *self, audioframe_t *frame)
{
	audioaec_t *aec = CONTAINING_RECORD(self, audioaec_t, base);
	apr_status_t status = APR_SUCCESS;
	
	if (aec->opt & AUDIO_AEC_OPT_READ_AS_CAPTURE) {
		aec->tmp_capture_frame.size = SUGGEST_FRAME_SIZE;
		status = aec->base.downstream->vtbl->read_frame(aec->base.downstream, &aec->tmp_capture_frame);
		if (status == 0) {
			if (aec->tmp_capture_frame.size == 0) {
				memset(aec->tmp_capture_frame.buffer, 0, aec->psize);
			}
			frame->dtmf = aec->tmp_capture_frame.dtmf;
			frame->size = aec->psize;
			speex_echo_capture(aec->state, (short*)aec->tmp_capture_frame.buffer, (short*)frame->buffer);
		}
	} else {
		status = aec->base.downstream->vtbl->read_frame(aec->base.downstream, frame);
		if (status != 0 || frame->size == 0) {
			memset(frame->buffer, 0, aec->psize);
			frame->size = aec->psize;
		}
		speex_echo_playback(aec->state, (short*)frame->buffer);
	}

	return status;
}

static apr_status_t write_frame(void *self, const audioframe_t *frame)
{
	audioaec_t *aec = CONTAINING_RECORD(self, audioaec_t, base);
	apr_status_t status = APR_SUCCESS;

	if (aec->opt & AUDIO_AEC_OPT_READ_AS_CAPTURE) {
		aec->tmp_capture_frame.dtmf = frame->dtmf;
		if (frame->size == 0) {
			aec->tmp_capture_frame.size = aec->psize;
			memset(aec->tmp_capture_frame.buffer, 0, aec->psize);
			speex_echo_playback(aec->state, (short*)aec->tmp_capture_frame.buffer);
			status = aec->base.downstream->vtbl->write_frame(aec->base.downstream, &aec->tmp_capture_frame);
		} else {
			speex_echo_playback(aec->state, (short*)frame->buffer);
			status = aec->base.downstream->vtbl->write_frame(aec->base.downstream, frame);
		}
	} else {
		if (frame->size == 0) {
			memset((void*)frame->buffer, 0, aec->psize); // because size is zero, so buffer can be use
		}
		aec->tmp_capture_frame.dtmf = frame->dtmf;
		aec->tmp_capture_frame.size = aec->psize;
		speex_echo_capture(aec->state, (short*)frame->buffer, (short*)aec->tmp_capture_frame.buffer);
		status = aec->base.downstream->vtbl->write_frame(aec->base.downstream, &aec->tmp_capture_frame);
	}

	return status;
}

static audiostream_vtbl_t g_stream_vtbl = {
	&read_frame,
	&write_frame,
};

apr_status_t audioaec_create(apr_pool_t *pool, audioengine_t *engine, int clock, int ptime, int opt, int latency, audioaec_t **p_aec)
{
	audioaec_t *aec;

	if (latency == 0)
		latency = 300;

	aec = apr_palloc(pool, sizeof(audioaec_t));
	memset(aec, 0, sizeof(audioaec_t));
	audiostream_init(engine, &g_stream_vtbl, &aec->base);
	aec->opt = opt;
	aec->clock = clock;
	aec->ptime = ptime;
	aec->psize = ptime * clock / 1000 * 2;
	aec->tmp_capture_frame.size = SUGGEST_FRAME_SIZE;
	aec->tmp_capture_frame.buffer = apr_palloc(pool, SUGGEST_FRAME_SIZE);
	aec->tmp_capture_frame.dtmf = 0;

	/* Set EC latency to 3/4 of output latency to reduce the
	 * possibility of missing/late reference frame.
	 */
	{
		//unsigned uLlatency = 440 * 3/4;
		int uLlatency = latency * 3 / 4;
		aec->state = speex_echo_state_init(ptime * clock /1000,clock * uLlatency / 1000);
	}
	
	*p_aec = aec;

	return APR_SUCCESS;
}

void audioaec_destroy(audioaec_t *aec)
{
	speex_echo_state_destroy(aec->state);
}