OpenSL的代码编写

#include <jni.h>
#include <string>
#include <SLES/OpenSLES.h>
#include <SLES/OpenSLES_Android.h>

static SLObjectItf engineItf = NULL;
SLEngineItf createSL()
{
 SLresult lresult;
 SLEngineItf en;
 lresult = slCreateEngine(&engineItf, 0, 0, 0, 0, 0);
 if(lresult != SL_RESULT_SUCCESS)return NULL;
 lresult = (*engineItf)->Realize(engineItf , SL_BOOLEAN_FALSE);
 if(lresult != SL_RESULT_SUCCESS)return NULL;
 lresult = (*engineItf)->GetInterface(engineItf , SL_IID_ENGINE , &en);
 if(lresult != SL_RESULT_SUCCESS)return NULL;
 return en;
}

void PcmCall(SLAndroidSimpleBufferQueueItf bf , void *context)
{
 static FILE *file = NULL;
 static char *buf = NULL;
 if(!buf)
 {
 buf = new char[1024 * 1024];
 }
 if(!file)
 {
 file = fopen("/sdcard/shape.pcm" , "rb");
 } 
 if(!file) return;
 
 if(feof(file) == 0)
 {
 int len = fread(buf , 1,1024 ,file);
 if(len>0)
 {
 (*bf)->Enqueue(bf , buf , len);
 }
 
 }
}
extern "C" JNIEXPORT jstring

JNICALL
Java_com_example_shang_opensl_MainActivity_stringFromJNI(
 JNIEnv *env,
 jobject /* this */) {
 std::string hello = "Hello from C++";

 //1.创建引擎
 SLEngineItf eng = createSL();



 //2.创建混音器
 SLObjectItf mix = NULL;
 (*eng)->CreateOutputMix(eng , &mix ,0 ,0 ,0);
 //实例化mix
 (*mix)->Realize(mix , SL_BOOLEAN_FALSE);

 SLDataLocator_OutputMix outMix = {SL_DATALOCATOR_OUTPUTMIX , mix};
 SLDataSink audioSink = {&outMix , 0};




 //配置音频信息
 //缓冲格式
 SLDataLocator_AndroidSimpleBufferQueue queue = {SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE
 , 10};
 //音频格式
 SLDataFormat_PCM pcm = {
 SL_DATAFORMAT_PCM,
 2,
 SL_SAMPLINGRATE_44_1,
 SL_PCMSAMPLEFORMAT_FIXED_16,
 SL_PCMSAMPLEFORMAT_FIXED_16,
 SL_SPEAKER_BACK_LEFT , //SL_SPEAKER_BACK_RIGHT,
 SL_BYTEORDER_LITTLEENDIAN //字节序,小断------还有大段

 };
 
 SLDataSource ds = {&queue , &pcm};
 
 
 
 //创建播放器
 SLObjectItf player = NULL;
 SLPlayItf iplayer = NULL ;
 const SLInterfaceID id[] = {SL_IID_BUFFERQUEUE};
 const SLboolean req[] = {SL_BOOLEAN_TRUE};
 (*eng)->CreateAudioPlayer(eng, &player, &ds, &audioSink, sizeof(id)/ sizeof(SLInterfaceID) , id , req); //如果只用player接口就不用传其他
 //实例化播放器 //参数，因为调用到内部类的接口，
 (*player)->Realize(player ,SL_BOOLEAN_FALSE); //所以必须传入其他参数
 //获取接口
 (*player)->GetInterface(player, SL_IID_PLAY, &iplayer);
 
 
 //获取队列的接口
 SLAndroidSimpleBufferQueueItf pcmQue = NULL;
 (*player)->GetInterface(player, SL_IID_BUFFERQUEUE, &pcmQue);
 
 //设置回调函数
 (*pcmQue)->RegisterCallback(pcmQue, PcmCall, 0);
 
 //设置播放状态
 (*iplayer)->SetPlayState(iplayer , SL_PLAYSTATE_PLAYING);
 
 //启动队列回调
 (*pcmQue)->Enqueue(pcmQue , "",1);
 
 return env->NewStringUTF(hello.c_str());
}