myvtm/Other/unix/libaudioframework/audioresample.c

#include "precompile.h"
#include "audioresample.h"
#include "audiolog.h"
#include "audiocontext.h"

#include <speex/speex_resampler.h>

static apr_status_t read_frame(void *self, audioframe_t *frame)
{
	apr_status_t status;
	audioresample_t *resample = CONTAINING_RECORD(self, audioresample_t, base);
	spx_uint32_t in_len;
	spx_uint32_t out_len;

	resample->read_resampled_frame.size = SUGGEST_FRAME_SIZE;
	status = resample->base.downstream->vtbl->read_frame(resample->base.downstream, 
		&resample->read_resampled_frame);
	if (status != APR_SUCCESS)
		return status;
	in_len = (spx_uint32_t)resample->downstream_psize / 2;
	speex_resampler_process_int(resample->read_state, 0, 
		(spx_int16_t*)&resample->read_resampled_frame.buffer[0], &in_len, 
		(spx_int16_t*)&frame->buffer[0], &out_len);
	frame->size = out_len * 2;
	frame->dtmf = resample->read_resampled_frame.dtmf;

	return APR_SUCCESS;
}

static apr_status_t write_frame(void *self, const audioframe_t *frame)
{
	apr_status_t status;
	audioresample_t *resample = CONTAINING_RECORD(self, audioresample_t, base);
	spx_uint32_t in_len;
	spx_uint32_t out_len;

	in_len = resample->upstream_psize / 2;
	speex_resampler_process_int(resample->write_state, 0, 
		(spx_int16_t*)&frame->buffer[0], &in_len, 
		(spx_int16_t*)&resample->write_resampled_frame.buffer[0], &out_len);
	resample->write_resampled_frame.size = out_len * 2;
	resample->write_resampled_frame.dtmf = frame->dtmf;
	
	status = resample->base.downstream->vtbl->write_frame(resample->base.downstream, 
		&resample->write_resampled_frame);
	if (status != APR_SUCCESS)
		return status;

	return APR_SUCCESS;
}

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

apr_status_t audioresample_create(apr_pool_t *pool,
								  audioengine_t *engine, 
								  int upstream_rate, 
								  int downstream_rate, 
								  int quality, 
								  audioresample_t **p_resample)
{
	audioresample_t *resample;

	resample = apr_palloc(pool, sizeof(audioresample_t));
	audiostream_init(engine, &g_stream_vtbl, &resample->base);
	resample->base.direction = STREAM_DIR_BOTH;
	resample->quality = quality;
	resample->upstream_rate = upstream_rate;
	resample->downstream_rate = downstream_rate;
	resample->upstream_psize = 2 * FRAME_TIME * upstream_rate / 1000;
	resample->downstream_psize = 2 * FRAME_TIME * downstream_rate / 1000;
	resample->read_resampled_frame.size = SUGGEST_FRAME_SIZE;
	resample->read_resampled_frame.buffer = apr_palloc(pool, SUGGEST_FRAME_SIZE);
	resample->read_resampled_frame.dtmf = 0;
	resample->write_resampled_frame.size = SUGGEST_FRAME_SIZE;
	resample->write_resampled_frame.buffer = apr_palloc(pool, SUGGEST_FRAME_SIZE);
	resample->write_resampled_frame.dtmf = 0;
	resample->read_state = speex_resampler_init(1, downstream_rate, upstream_rate, quality, NULL);
	resample->write_state = speex_resampler_init(1, upstream_rate, downstream_rate, quality, NULL);

	*p_resample = resample;

	return APR_SUCCESS;
}

void audioresample_destroy(audioresample_t *resample)
{
	speex_resampler_destroy(resample->read_state);
	speex_resampler_destroy(resample->write_state);
}