使用OpenSL ES 播放PCM数据(主要用于拷贝)

资料:
https://github.com/googlesamples/android-ndk

里面找到

https://github.com/googlesamples/android-ndk/tree/master/native-audio

里面是google 的模板代码

sd 卡根目录有一个output.pcm 的数据

java 的代码

public class MainActivity extends AppCompatActivity {

    static {
        System.loadLibrary("native-lib");
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public native void palypcm(String url);

    public void play(View view) {

        String path = "/mnt/sdcard/output.pcm";
        palypcm(path);
    }
}

OpenSL ES 播放pcm的代码

#include <jni.h>
#include <string>


extern "C"
{
#include <SLES/OpenSLES.h>
#include <SLES/OpenSLES_Android.h>
}

#include <android/log.h>
#define LOGI(FORMAT,...) __android_log_print(ANDROID_LOG_INFO,"jniLib",FORMAT,##__VA_ARGS__);
#define LOGE(FORMAT,...) __android_log_print(ANDROID_LOG_ERROR,"jniLib",FORMAT,##__VA_ARGS__);

// 引擎接口
SLObjectItf engineObject = NULL;
SLEngineItf engineEngine = NULL;

//混音器
SLObjectItf outputMixObject = NULL;
SLEnvironmentalReverbItf outputMixEnvironmentalReverb = NULL;
SLEnvironmentalReverbSettings reverbSettings = SL_I3DL2_ENVIRONMENT_PRESET_STONECORRIDOR;


//pcm
SLObjectItf pcmPlayerObject = NULL;
SLPlayItf pcmPlayerPlay = NULL;
SLVolumeItf pcmPlayerVolume = NULL;

//缓冲器队列接口
SLAndroidSimpleBufferQueueItf pcmBufferQueue;

FILE *pcmFile;
void *buffer;

uint8_t *out_buffer;

void getPcmData(void **pcm)
{
    //是否读到结尾
    while(!feof(pcmFile))
    {
        /**
         * size_t   fread(   void   *buffer,   size_t   size,   size_t   count,   FILE   *stream   ) 
  buffer   是读取的数据存放的内存的指针（可以是数组，也可以是新开辟的空间，buffer就是一个索引）   
    size       是每次读取的字节数   
  count     是读取次数   
  strean   是要读取的文件的指针   
  例如   从文件fp里读取100个字节   可用以下语句   
    
  fread(buffer,100,1,fp)   
  fread(buffer,50,2,fp)   
  fread(buffer,1,100,fp)   
         */
        fread(out_buffer, 44100 * 2 * 2, 1, pcmFile);
        if(out_buffer == NULL)
        {
            LOGI("%s", "read end");
            break;
        } else{
            LOGI("%s", "reading");
        }
        *pcm = out_buffer;
        break;
    }
}

void pcmBufferCallBack(SLAndroidSimpleBufferQueueItf bf, void * context)
{
    //assert(NULL == context);
    getPcmData(&buffer);
    // for streaming playback, replace this test by logic to find and fill the next buffer
    if (NULL != buffer) {
        SLresult result;
        // enqueue another buffer
        result = (*pcmBufferQueue)->Enqueue(pcmBufferQueue, buffer, 44100 * 2 * 2);
        // the most likely other result is SL_RESULT_BUFFER_INSUFFICIENT,
        // which for this code example would indicate a programming error
    }
}

extern "C"
JNIEXPORT void JNICALL
Java_com_example_androidopenslaudio_MainActivity_palypcm(JNIEnv *env, jobject instance,
                                                         jstring url_) {
    const char *url = env->GetStringUTFChars(url_, 0);

    // TODO
    //读取pcm文件
    pcmFile = fopen(url, "r");
    if(pcmFile == NULL)
    {
        LOGE("%s", "fopen file error");
        return;
    }
    out_buffer = (uint8_t *) malloc(44100 * 2 * 2);


    SLresult result;
    //第一步------------------------------------------
    // 创建引擎对象
    slCreateEngine(&engineObject, 0, 0, 0, 0, 0);
    (*engineObject)->Realize(engineObject, SL_BOOLEAN_FALSE);
    (*engineObject)->GetInterface(engineObject, SL_IID_ENGINE, &engineEngine);


    //第二步-------------------------------------------
    // 创建混音器
    const SLInterfaceID mids[1] = {SL_IID_ENVIRONMENTALREVERB};
    const SLboolean mreq[1] = {SL_BOOLEAN_FALSE};
    result = (*engineEngine)->CreateOutputMix(engineEngine, &outputMixObject, 1, mids, mreq);
    (void)result;
    result = (*outputMixObject)->Realize(outputMixObject, SL_BOOLEAN_FALSE);
    (void)result;
    result = (*outputMixObject)->GetInterface(outputMixObject, SL_IID_ENVIRONMENTALREVERB, &outputMixEnvironmentalReverb);
    if (SL_RESULT_SUCCESS == result) {
        result = (*outputMixEnvironmentalReverb)->SetEnvironmentalReverbProperties(
                outputMixEnvironmentalReverb, &reverbSettings);
        (void)result;
    }
    SLDataLocator_OutputMix outputMix = {SL_DATALOCATOR_OUTPUTMIX, outputMixObject};

    // 第三步--------------------------------------------
    // 创建播放器
    SLDataLocator_AndroidSimpleBufferQueue android_queue={SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE,2};
    SLDataFormat_PCM pcm={
            SL_DATAFORMAT_PCM,//播放pcm格式的数据
            2,//2个声道（立体声）
            SL_SAMPLINGRATE_44_1,//44100hz的频率
            SL_PCMSAMPLEFORMAT_FIXED_16,//位数 16位
            SL_PCMSAMPLEFORMAT_FIXED_16,//和位数一致就行
            SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT,//立体声（前左前右）
            SL_BYTEORDER_LITTLEENDIAN//结束标志
    };

    SLDataSource slDataSource = {&android_queue, &pcm};
    SLDataSink audioSnk = {&outputMix, NULL};
    const SLInterfaceID ids[3] = {SL_IID_BUFFERQUEUE, SL_IID_EFFECTSEND, SL_IID_VOLUME};
    const SLboolean req[3] = {SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE};

    result = (*engineEngine)->CreateAudioPlayer(engineEngine, &pcmPlayerObject, &slDataSource, &audioSnk, 3, ids, req);
    // 初始化播放器
    (*pcmPlayerObject)->Realize(pcmPlayerObject, SL_BOOLEAN_FALSE);

    //得到接口后调用  获取Player接口
    (*pcmPlayerObject)->GetInterface(pcmPlayerObject, SL_IID_PLAY, &pcmPlayerPlay);

    //第四步---------------------------------------
    // 创建缓冲区和回调函数
    (*pcmPlayerObject)->GetInterface(pcmPlayerObject, SL_IID_BUFFERQUEUE, &pcmBufferQueue);

    //缓冲接口回调
    (*pcmBufferQueue)->RegisterCallback(pcmBufferQueue, pcmBufferCallBack, NULL);
    //获取音量接口
    (*pcmPlayerObject)->GetInterface(pcmPlayerObject, SL_IID_VOLUME, &pcmPlayerVolume);

    //第五步----------------------------------------
    // 设置播放状态
    (*pcmPlayerPlay)->SetPlayState(pcmPlayerPlay, SL_PLAYSTATE_PLAYING);


    //第六步----------------------------------------
    // 主动调用回调函数开始工作
    pcmBufferCallBack(pcmBufferQueue, NULL);

    env->ReleaseStringUTFChars(url_, url);
}

使用OpenSL ES 播放PCM数据(主要用于拷贝)

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