This examples shows to use of OpenSL ES framework in native files to play audio.

Include following two header files in your project.

[code lang=”c”]
#include <SLES/OpenSLES.h>
#include <SLES/OpenSLES_Android.h>
[/code]

Now, create necessary class objects.

[code lang=”c”]
// engine interfaces
static SLObjectItf engineObject = NULL;
static SLEngineItf engineEngine;

// output mix interfaces
static SLObjectItf outputMixObject = NULL;

// buffer queue player interfaces
static SLObjectItf bqPlayerObject = NULL;
static SLPlayItf bqPlayerPlay;
static SLAndroidSimpleBufferQueueItf bqPlayerBufferQueue;
static SLEffectSendItf bqPlayerEffectSend;
static SLVolumeItf bqPlayerVolume;
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Below function create and initilize engine.

[code lang=”c”]
static void createEngine() {
SLresult result;

// create engine
result = slCreateEngine(&engineObject, 0, NULL, 0, NULL, NULL);
assert(SL_RESULT_SUCCESS == result);
(void) result;

// realize the engine
result = (*engineObject)->Realize(engineObject, SL_BOOLEAN_FALSE);
assert(SL_RESULT_SUCCESS == result);
(void) result;

// get the engine interface, which is needed in order to create other objects
result = (*engineObject)->GetInterface(engineObject, SL_IID_ENGINE, &engineEngine);
assert(SL_RESULT_SUCCESS == result);
(void) result;

//const SLInterfaceID ids[1] = {SL_IID_ENVIRONMENTALREVERB};
//const SLboolean req[1] = {SL_BOOLEAN_FALSE};

// create output mix,
result = (*engineEngine)->CreateOutputMix(engineEngine, &outputMixObject, 0, 0, 0);
assert(SL_RESULT_SUCCESS == result);
(void) result;

// realize the output mix
result = (*outputMixObject)->Realize(outputMixObject, SL_BOOLEAN_FALSE);
assert(SL_RESULT_SUCCESS == result);
(void) result;
}
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Below function create and initilize audio player.

[code lang=”c”]
static void createAudioPlayer(gint frequency) {
SLresult result;
// configure audio source
SLDataLocator_AndroidSimpleBufferQueue loc_bufq = {
SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE, 32 };

SLDataFormat_PCM format_pcm = { SL_DATAFORMAT_PCM, 2, SL_SAMPLINGRATE_44_1,
SL_PCMSAMPLEFORMAT_FIXED_16, SL_PCMSAMPLEFORMAT_FIXED_16,
SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT,
SL_BYTEORDER_LITTLEENDIAN };
SLDataSource audioSrc = { &loc_bufq, &format_pcm };

// configure audio sink
SLDataLocator_OutputMix loc_outmix = { SL_DATALOCATOR_OUTPUTMIX,
outputMixObject };
SLDataSink audioSnk = { &loc_outmix, NULL };

// create audio player
const SLInterfaceID ids[2] = { SL_IID_BUFFERQUEUE, /*SL_IID_EFFECTSEND,*/
SL_IID_VOLUME };
const SLboolean req[2] =
{ SL_BOOLEAN_TRUE, /*SL_BOOLEAN_TRUE,*/ SL_BOOLEAN_TRUE };
result = (*engineEngine)->CreateAudioPlayer(engineEngine, &bqPlayerObject,
&audioSrc, &audioSnk, 2, ids, req);
assert(SL_RESULT_SUCCESS == result);
(void) result;

// realize the player
result = (*bqPlayerObject)->Realize(bqPlayerObject, SL_BOOLEAN_FALSE);
assert(SL_RESULT_SUCCESS == result);
(void) result;

// get the play interface
result = (*bqPlayerObject)->GetInterface(bqPlayerObject, SL_IID_PLAY,
&bqPlayerPlay);
assert(SL_RESULT_SUCCESS == result);
(void) result;

// get the buffer queue interface
result = (*bqPlayerObject)->GetInterface(bqPlayerObject, SL_IID_BUFFERQUEUE,
&bqPlayerBufferQueue);
assert(SL_RESULT_SUCCESS == result);
(void) result;

// get the effect send interface
//result = (*bqPlayerObject)->GetInterface(bqPlayerObject, SL_IID_EFFECTSEND,
// &bqPlayerEffectSend);
//assert(SL_RESULT_SUCCESS == result);
//(void) result;

// get the volume interface
result = (*bqPlayerObject)->GetInterface(bqPlayerObject, SL_IID_VOLUME,
&bqPlayerVolume);
assert(SL_RESULT_SUCCESS == result);
(void) result;

// set the player’s state to playing
result = (*bqPlayerPlay)->SetPlayState(bqPlayerPlay, SL_PLAYSTATE_PLAYING);
assert(SL_RESULT_SUCCESS == result);
(void) result;
}
[/code]

The following codes are create and initilize engine and audio player.

[code lang=”c”]
createEngine();
createAudioPlayer(frequency);
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The below code enque audio data into buffer queue.

[code lang=”c”]
// enqueue another buffer
result = (*bqPlayerBufferQueue)->Enqueue(bqPlayerBufferQueue, audio_data, size);
if (result == SL_RESULT_BUFFER_INSUFFICIENT) {
__android_log_write(6, “spice-gstaudio”, “Enqueue failed!!”);
return;
}
[/code]