myvtm/Other/win/libaudioframework/audiomixer.c

#include "precompile.h"
#include "audiomixer.h"
#include "audioengine.h"

static apr_status_t read_frame(void *self, audioframe_t *frame)
{
	audiomixer_t *mixer = CONTAINING_RECORD(self, audiomixer_t, base);
	apr_status_t status;

	if (mixer->base.downstream == NULL)
		return APR_EGENERAL;

	status = mixer->base.downstream->vtbl->read_frame(mixer->base.downstream, frame);

	if (status == APR_SUCCESS && frame->size) {
		int mixbuf[SUGGEST_FRAME_SIZE];
		int mixcnt;
		int mixdtmf;
		int frame_samples;
		int frame_size;
		int i;
		int kk;

		if (mixer->arr_stream->nelts == 0)
			return status;

		frame_samples = frame->size >> 1;
		frame_size = frame->size;
		mixcnt = 0;
		mixdtmf = 0;
		memset(mixbuf, 0, sizeof(mixbuf));

		for (i = 0; i < mixer->arr_stream->nelts; ++i) {
			audiostream_t *stream = APR_ARRAY_IDX(mixer->arr_stream, i, audiostream_t*);
			if (audiostream_get_direction(stream) & STREAM_DIR_READ) {
				short frm_buf[SUGGEST_FRAME_SIZE];
				audioframe_t frm = {(char*)&frm_buf[0], SUGGEST_FRAME_SIZE};
				status = stream->vtbl->read_frame(stream, &frm);
				if (status == APR_SUCCESS && frm.size == frame->size) {
					for (kk = 0; kk < frame_samples; ++kk)
						mixbuf[kk] += frm_buf[kk];
					if (mixdtmf == 0 &&  frm.dtmf)
						mixdtmf = frm.dtmf;
					mixcnt ++;
				}
			}
		}

		if (mixcnt > 0) {
			short *dst = (short*)frame->buffer;
			for (kk = 0; kk < frame_samples; ++kk) {
				int t = mixbuf[kk] + dst[kk];
				if (t > 32767)
					t = 32767;
				if (t < -32767)
					t = -32767;
				dst[kk] = (short)t;
			}
			if (frame->dtmf == 0)
				frame->dtmf = mixdtmf;
		}

	} else {
		return status;
	}

	return APR_SUCCESS;
}

static apr_status_t write_frame(void *self, const audioframe_t *frame)
{
	audiomixer_t *mixer = CONTAINING_RECORD(self, audiomixer_t, base);
	if (mixer->base.downstream) {
		return mixer->base.downstream->vtbl->write_frame(mixer->base.downstream, frame);
	} else {
		return APR_EGENERAL;
	}	
}

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

apr_status_t audiomixer_create(apr_pool_t *pool, audioengine_t *engine, audiomixer_t **p_mixer)
{
	audiomixer_t *mixer;

	mixer = apr_palloc(pool, sizeof(audiomixer_t));
	memset(mixer, 0, sizeof(audiomixer_t));
	mixer->arr_stream = apr_array_make(pool, 3, sizeof(audiostream_t*));
	audiostream_init(engine, &g_stream_vtbl, &mixer->base);

	*p_mixer = mixer;

	return APR_SUCCESS;	
}

void audiomixer_destroy(audiomixer_t *mixer)
{
	
}

apr_status_t audiomixer_add_stream(audiomixer_t *mixer, audiostream_t *stream)
{
	if (!mixer || !stream)
		return APR_EINVAL;
	APR_ARRAY_PUSH(mixer->arr_stream, audiostream_t*) = stream;
	return APR_SUCCESS;
}

apr_status_t audiomixer_remove_stream(audiomixer_t *mixer, audiostream_t *stream)
{
	int i;
	if (!mixer || !stream)
		return APR_EINVAL;
	for (i = 0; i < mixer->arr_stream->nelts; ++i) {
		audiostream_t *t = APR_ARRAY_IDX(mixer->arr_stream, i, audiostream_t*);
		if (t == stream) {
			if (i != mixer->arr_stream->nelts-1)
				APR_ARRAY_IDX(mixer->arr_stream, i, audiostream_t*) = APR_ARRAY_IDX(mixer->arr_stream, mixer->arr_stream->nelts-1, audiostream_t*);
			apr_array_pop(mixer->arr_stream);
			return APR_SUCCESS;
		}
	}
	return APR_NOTFOUND;
}