如何從Android中的Media Recorder獲取音頻流

Question

我想在android中制作流媒體錄音機。 我不確定如何獲取音頻流以及如何設置音頻流的緩沖區大小。

下面是我的媒體記錄器類

public class MyMediaRecorder {

    final MediaRecorder recorder = new MediaRecorder();
    final File path;

    /**
     * Creates a new audio recording at the given path (relative to root of SD
     * card).
     */
    public MyMediaRecorder(File path) {
        this.path = path;
    }



    /**
     * Starts a new recording.
     */
    public void start() throws IOException {
        String state = android.os.Environment.getExternalStorageState();
        if (!state.equals(android.os.Environment.MEDIA_MOUNTED)) {
            throw new IOException("SD Card is not mounted.  It is " + state
                    + ".");
        }

        // make sure the directory we plan to store the recording in exists


        recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        recorder.setOutputFile(path.getAbsolutePath());
        recorder.prepare();
        recorder.start();
    }

    /**
     * Stops a recording that has been previously started.
     */
    public void stop() throws IOException {
        recorder.stop();
        recorder.release();
    }
}

在錄制開始時，我需要獲取緩沖區大小並將其發送到服務器並行錄制音頻。 我應該使用 Media Recorder 的 Audio Record 和 Audio track instaed 嗎？ 請建議我該怎么做

Answer 1

您應該使用AudioRecord 。 這是一個簡單的代碼，展示了如何使用AudioRecord類。

final int sampleRate = 48000;
final int channelConfig = AudioFormat.CHANNEL_IN_MONO;
final int audioFormat = AudioFormat.ENCODING_PCM_16BIT;

int minBufferSize = AudioRecord.getMinBufferSize(sampleRate, channelConfig, audioFormat);
AudioRecord microphone = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleRate, channelConfig, audioFormat, minBufferSize * 10);

microphone.startRecording();

//Since audioformat is 16 bit, we need to create a 16 bit (short data type) buffer
short[] buffer = new short[1024];

while(!stopped) {

    int readSize = microphone.read(buffer, 0, buffer.length);
    sendDataToServer(buffer, readSize);

}

microphone.stop();
microphone.release();

如果您需要實時錄音機和流媒體，您應該注意性能並盡快讀取所有數據並管理它們以發送到服務器。 Github 中有很多項目，你可以重用它們並從他們的想法中學習。 我在這里分享了其中的一些（特別是錄音機類），但您可以搜索並找到更多。
1. 錄音機
2. FullDuplexNetworkAudioCallService
3. 麥克風錄音機