attachAuxEffect and OpenSL ES

Question

attachAuxEffect and OpenSL ES

androidaudiotrackopensl

4

当在Android中使用AudioTrack时，您可以调用attachAuxEffect来附加音频效果。在使用OpenSL ES进行音频播放时是否有类似的方法或者途径呢？我似乎找不到类似的方法。

- William Seemann

1个回答

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- bonnyz · Answer 1

在你的NDK-home/samples/native-audio目录下有一个示例，展示了如何使用OpenSL ES本地音频。

看一下这段代码片段（我们在这里应用了混响效果）：

...
// create the engine and output mix objects
void Java_com_example_nativeaudio_NativeAudio_createEngine(JNIEnv* env, jclass clazz)
{
    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;

    // create output mix, with environmental reverb specified as a non-required interface
    const SLInterfaceID ids[1] = {SL_IID_ENVIRONMENTALREVERB};
    const SLboolean req[1] = {SL_BOOLEAN_FALSE};
    result = (*engineEngine)->CreateOutputMix(engineEngine, &outputMixObject, 1, ids, req);
    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;

    // get the environmental reverb interface
    // this could fail if the environmental reverb effect is not available,
    // either because the feature is not present, excessive CPU load, or
    // the required MODIFY_AUDIO_SETTINGS permission was not requested and granted
    result = (*outputMixObject)->GetInterface(outputMixObject, SL_IID_ENVIRONMENTALREVERB,
            &outputMixEnvironmentalReverb);
    if (SL_RESULT_SUCCESS == result) {
        result = (*outputMixEnvironmentalReverb)->SetEnvironmentalReverbProperties(
                outputMixEnvironmentalReverb, &reverbSettings);
        (void)result;
    }
    // ignore unsuccessful result codes for environmental reverb, as it is optional for this example

}

请注意，Android OpenSL ES 实现是 OpenSL ES 的子集，而 OpenSL ES 又是 OpenSL 的子集：某些效果可能无法在所有设备上使用。关于这一方面的非常简要的说明可以在此处找到。