java layer调用native层的android_media_AudioTrack_get_min_buf

// ----------------------------------------------------------------------------
// returns the minimum required size for the successful creation of a streaming AudioTrack
// returns -1 if there was an error querying the hardware.
static jint android_media_AudioTrack_get_min_buff_size(JNIEnv *env,jobject thiz,jint sampleRateInHertz,jint channelCount,jint audioFormat) {

    size_t frameCount;
    const status_t status = AudioTrack::getMinFrameCount(&frameCount,AUDIO_STREAM_DEFAULT,sampleRateInHertz);
    if (status != NO_ERROR) {
        ALOGE("AudioTrack::getMinFrameCount() for sample rate %d failed with status %d",sampleRateInHertz,status);
        return -1;
    }
    const audio_format_t format = audioFormatToNative(audioFormat);
    if (audio_has_proportional_frames(format)) {
        const size_t bytesPerSample = audio_bytes_per_sample(format);
        return frameCount * channelCount * bytesPerSample;
    } else {
        return frameCount;
    }
}