Audio/sample-streamer-multi/render.cpp

Multiple playback of large wav files

This is an extension of the sampleStreamer example. Functionality of opening files, managing buffers, retrieving samples etc. is built into the sampleStream class, making it easier to have multiple playback streams at the same time. Streams can be paused/unpaused with the option of fading in/out the playback.

/*
 ____  _____ _        _
| __ )| ____| |      / \
|  _ \|  _| | |     / _ \
| |_) | |___| |___ / ___ \
|____/|_____|_____/_/   \_\
http://bela.io
*/
#include <Bela.h>
#include <cmath>
#include <SampleStream.h>

#define NUM_CHANNELS 2    // NUMBER OF CHANNELS IN THE FILE
#define BUFFER_LEN 44100   // BUFFER LENGTH
#define NUM_STREAMS 20

SampleStream *sampleStream[NUM_STREAMS];
AuxiliaryTask gFillBuffersTask;
int gStopThreads = 0;
int gTaskStopped = 0;
int gCount = 0;

void fillBuffers(void*) {
    for(int i=0;i<NUM_STREAMS;i++) {
        if(sampleStream[i]->bufferNeedsFilled())
            sampleStream[i]->fillBuffer();
    }
}

bool setup(BelaContext *context, void *userData)
{

    for(int i=0;i<NUM_STREAMS;i++) {
        sampleStream[i] = new SampleStream("waves.wav",NUM_CHANNELS,BUFFER_LEN);
    }

    // Initialise auxiliary tasks
        if((gFillBuffersTask = Bela_createAuxiliaryTask(&fillBuffers, 90, "fill-buffer")) == 0)
                return false;

        return true;
}

void render(BelaContext *context, void *userData)
{

    // check if buffers need filling
    Bela_scheduleAuxiliaryTask(gFillBuffersTask);

    // ***** remove this -- it's just a demonstration
    // random playback toggling
    for(int i=0;i<NUM_STREAMS;i++) {
        // randomly pauses/unpauses + fades in/out streams
        if((rand() / (float)RAND_MAX)>0.9999)
            sampleStream[i]->togglePlaybackWithFade(0.1);
            // the above function can also be overloaded specifying the state
            // of playback to toggle - i.e. togglePlaybackWithFade(1,0.1)
            // same applies to togglePlayback()
        /*
         * demonstrates dynamically reloading samples
         * (TODO: this should really be done in a separate thread)
         */
        // if((rand() / (float)RAND_MAX)>0.9999) {
        //     // only change sample if sampleStream isn't playing
        //     if(!sampleStream[i]->isPlaying())
        //         sampleStream[i]->openFile("chimes_stereo.wav",NUM_CHANNELS,BUFFER_LEN);
        // }
    }
    // *****

    for(unsigned int n = 0; n < context->audioFrames; n++) {

        for(int i=0;i<NUM_STREAMS;i++) {
            // process frames for each sampleStream objects (get samples per channel below)
            sampleStream[i]->processFrame();
        }

        for(unsigned int channel = 0; channel < context->audioOutChannels; channel++) {

            float out = 0;
            for(int i=0;i<NUM_STREAMS;i++) {
                // get samples for each channel from each sampleStream object
                out += sampleStream[i]->getSample(channel);
            }
            // you may need to attenuate the output depending on the amount of streams playing back
            audioWrite(context, n, channel, out);

        }

    }
}


void cleanup(BelaContext *context, void *userData)
{
    for(int i=0;i<NUM_STREAMS;i++) {
        delete sampleStream[i];
    }
}