无法播放编码为ENCODING_PCM_FLOAT的PCM流

Question

我知道有很多关于这个话题的问题。但我对ENCODING_PCM_FLOAT有意见。

我有一个包含以下信息的PCM流：

Encoding : 32 bit float
Byte order: Little Endian
Channels : 2 channels ( stereo)
Sample Rate : 48000

我想把它喂给AudioTrack。我使用以下API：

private final int SAMPLE_RATE = 48000;
private final int CHANNEL_COUNT = AudioFormat.CHANNEL_OUT_STEREO;
private final int ENCODING = AudioFormat.ENCODING_PCM_FLOAT;
...
int bufferSize = AudioTrack.getMinBufferSize(SAMPLE_RATE, CHANNEL_COUNT, ENCODING);    
AudioAttributes audioAttributes = new AudioAttributes.Builder()
    .setUsage(AudioAttributes.USAGE_MEDIA)
    .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
    .build();
AudioFormat audioFormat = new AudioFormat.Builder()
    .setEncoding(ENCODING)
    .setSampleRate(SAMPLE_RATE)
    .build();
audioTrack = new AudioTrack(audioAttributes, audioFormat, bufferSize
    , AudioTrack.MODE_STREAM, AudioManager.AUDIO_SESSION_ID_GENERATE);
audioTrack.play();

然后我开始听音频流：

    private void startListening() {
        while (true) {
            try {
                byte[] buffer = new byte[8192];

                DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
                mSocket.receive(packet);

                FloatBuffer floatBuffer = ByteBuffer.wrap(packet.getData()).asFloatBuffer();
                float[] audioFloats = new float[floatBuffer.capacity()];
                floatBuffer.get(audioFloats);

                for (int i = 0; i < audioFloats.length; i++) {
                    audioFloats[i] = audioFloats[i] / 0x8000000;
                }

                audioTrack.write(audioFloats, 0, audioFloats.length, AudioTrack.WRITE_NON_BLOCKING);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

但我根本听不到任何声音。我可以将字节数组作为PCM_16播放(无需将其转换为浮点数组)，但它包含太多噪声。所以我认为流输入不是问题所在。

如果你有任何想法，请让我知道。

感谢您的阅读！

Answer 1

for (int i = 0; i < audioFloats.length; i++) {
    audioFloats[i] = audioFloats[i] / 0x8000000;
}

我是个笨蛋，上面的代码块是不需要的。移除后，音频播放正常。