一、遇到问题

使用RK3399的开发板，跑Android8.1系统
一开始插上外置的USB麦克风的时候，无法使用

二、分析问题

查看USB麦克风拔插过程的debug打印日志

在这里插入图片描述

插入USB麦克风后，adb 查询当前声卡信息
cat cards

在这里插入图片描述

三、解决问题

通过分析发现，USB麦克风设备没有枚举出来，节点都没挂载上去
这时候就怀疑是硬件问题，USB麦克风设备故障，或者USB供电不足，或者USB布线问题
通过交叉实验，拔插不同的USB口，更换RK3399开发板，更换USB麦克风
最后确认是USB麦克风设备故障，更换USB麦克风后，再cat cards就能查询出USB-AUDIO设备

在这里插入图片描述

使用USB麦克风设备
- 首先需要正常识别到该USB-AUDIO设备
- 其次Android系统会自动切换MIC录音源
  - 如果没有插入USB麦克风设备，则Android系统使用主板上模拟MIC
  - 如果插入USB麦克风设备，则Android系统就会切换到USB麦克风

四、录音源码分析

audioSource: MediaRecorder.AudioSource.CAMCORDER, MediaRecorder.AudioSource.MIC 等
sampleRateInHz: 常用的有: 8000,11025,16000,22050,44100,96000；44100Hz是唯一可以保证兼容所有Android手机的采样率
channelConfig: AudioFormat.CHANNEL_CONFIGURATION_DEFAULT，常用的是 CHANNEL_IN_MONO（单通道）CHANNEL_IN_STEREO（双通道）
audioFormat: AudioFormat.ENCODING_PCM_16BIT, 测试中要捕获PCM数据
bufferSizeInBytes: 由AudioRecord.getMinBufferSize(sampleRateInHz, channelConfig, audioFormat)获得

public AudioRecord(int audioSource, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes)

AudioRecord.startRecording();

AudioRecord.stop();

AudioRecord.read(byte[] audioData, int offsetInBytes, int sizeInBytes);

public class AudioCapturer {
    
    

    private static final String TAG = "AudioCapturer";
	
    private static final int DEFAULT_SOURCE = MediaRecorder.AudioSource.MIC;
    private static final int DEFAULT_SAMPLE_RATE = 44100;
    private static final int DEFAULT_CHANNEL_CONFIG = AudioFormat.CHANNEL_IN_STEREO;
    private static final int DEFAULT_AUDIO_FORMAT = AudioFormat.ENCODING_PCM_16BIT;

    private AudioRecord mAudioRecord;
    private int mMinBufferSize = 0;
	
    private Thread mCaptureThread; 	
    private boolean mIsCaptureStarted = false;
    private volatile boolean mIsLoopExit = false;

    private OnAudioFrameCapturedListener mAudioFrameCapturedListener;

    public interface OnAudioFrameCapturedListener {
    
    
        public void onAudioFrameCaptured(byte[] audioData);
    }	

    public boolean isCaptureStarted() {
    
    		
        return mIsCaptureStarted;
    }

    public void setOnAudioFrameCapturedListener(OnAudioFrameCapturedListener listener) {
    
    
        mAudioFrameCapturedListener = listener;
    }

    public boolean startCapture() {
    
    
        return startCapture(DEFAULT_SOURCE, DEFAULT_SAMPLE_RATE, DEFAULT_CHANNEL_CONFIG,
            DEFAULT_AUDIO_FORMAT);
    }

    public boolean startCapture(int audioSource, int sampleRateInHz, int channelConfig, int audioFormat) {
    
    

        if (mIsCaptureStarted) {
    
    
            Log.e(TAG, "Capture already started !");
            return false;
        }
    
        mMinBufferSize = AudioRecord.getMinBufferSize(sampleRateInHz,channelConfig,audioFormat);
        if (mMinBufferSize == AudioRecord.ERROR_BAD_VALUE) {
    
    
            Log.e(TAG, "Invalid parameter !");
            return false;
        }
        Log.d(TAG , "getMinBufferSize = "+mMinBufferSize+" bytes !");
		
        mAudioRecord = new AudioRecord(audioSource,sampleRateInHz,channelConfig,audioFormat,mMinBufferSize);				
        if (mAudioRecord.getState() == AudioRecord.STATE_UNINITIALIZED) {
    
    
    	    Log.e(TAG, "AudioRecord initialize fail !");
    	    return false;
        }		

        mAudioRecord.startRecording();

        mIsLoopExit = false;
        mCaptureThread = new Thread(new AudioCaptureRunnable());
        mCaptureThread.start();

        mIsCaptureStarted = true;

        Log.d(TAG, "Start audio capture success !");

        return true;
    }

    public void stopCapture() {
    
    

        if (!mIsCaptureStarted) {
    
    
            return;
        }

        mIsLoopExit = true;		
        try {
    
    
            mCaptureThread.interrupt();
            mCaptureThread.join(1000);
        } 
        catch (InterruptedException e) {
    
    		
            e.printStackTrace();
        }

        if (mAudioRecord.getRecordingState() == AudioRecord.RECORDSTATE_RECORDING) {
    
    
            mAudioRecord.stop();						
        }

        mAudioRecord.release();		
	
        mIsCaptureStarted = false;
        mAudioFrameCapturedListener = null;

        Log.d(TAG, "Stop audio capture success !");
    }

    private class AudioCaptureRunnable implements Runnable {
    
    		
	
        @Override
        public void run() {
    
    

            while (!mIsLoopExit) {
    
    

                byte[] buffer = new byte[mMinBufferSize];

                int ret = mAudioRecord.read(buffer, 0, mMinBufferSize);				
                if (ret == AudioRecord.ERROR_INVALID_OPERATION) {
    
    
                    Log.e(TAG , "Error ERROR_INVALID_OPERATION");
                } 
                else if (ret == AudioRecord.ERROR_BAD_VALUE) {
    
    
                    Log.e(TAG , "Error ERROR_BAD_VALUE");
                } 
                else {
    
     
                    if (mAudioFrameCapturedListener != null) {
    
    
                        mAudioFrameCapturedListener.onAudioFrameCaptured(buffer);
                    }   
                    Log.d(TAG , "OK, Captured "+ret+" bytes !");
                }			
                
                SystemClock.sleep(10);
            }		
        }    
    }
}

五、播放源码分析

streamType:
- AudioManager.STREAM_VOCIE_CALL：电话声音
- AudioManager.STREAM_SYSTEM：系统声音
- AudioManager.STREAM_RING：铃声
- AudioManager.STREAM_MUSCI：音乐声
- AudioManager.STREAM_ALARM：警告声
- AudioManager.STREAM_NOTIFICATION：通知声
sampleRateInHz: 常用的有: 8000,11025,16000,22050,44100,96000；44100Hz是唯一可以保证兼容所有Android手机的采样率
channelConfig: AudioFormat.CHANNEL_CONFIGURATION_DEFAULT，常用的是 CHANNEL_IN_MONO（单通道）
audioFormat: AudioFormat.ENCODING_PCM_16BIT, 测试中要捕获PCM数据
bufferSizeInBytes: 由AudioRecord.getMinBufferSize(sampleRateInHz, channelConfig, audioFormat)获得
mode:
- AudioTrack.MODE_STATIC，一次性将所有的数据都写入播放缓冲区，简单高效
- AudioTrack.MODE_STREAM，按照一定的时间间隔不间断地写入音频数据

public AudioTrack(int streamType, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes, int mode)

AudioTrack.play();
AudioTrack.stop();

import android.util.Log;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;

public class AudioPlayer {
    
    
    
    private static final String TAG = "AudioPlayer";

    private static final int DEFAULT_STREAM_TYPE = AudioManager.STREAM_MUSIC;
    private static final int DEFAULT_SAMPLE_RATE = 44100;
    private static final int DEFAULT_CHANNEL_CONFIG = AudioFormat.CHANNEL_IN_STEREO;
    private static final int DEFAULT_AUDIO_FORMAT = AudioFormat.ENCODING_PCM_16BIT;
    private static final int DEFAULT_PLAY_MODE = AudioTrack.MODE_STREAM;
            
    private boolean mIsPlayStarted = false;
    private int mMinBufferSize = 0;
    private AudioTrack mAudioTrack;  
    
    public boolean startPlayer() {
    
    
        return startPlayer(DEFAULT_STREAM_TYPE,DEFAULT_SAMPLE_RATE,DEFAULT_CHANNEL_CONFIG,DEFAULT_AUDIO_FORMAT);
    }
    
    public boolean startPlayer(int streamType, int sampleRateInHz, int channelConfig, int audioFormat) {
    
    
        
        if (mIsPlayStarted) {
    
    
            Log.e(TAG, "Player already started !");
            return false;
        }
        
        mMinBufferSize = AudioTrack.getMinBufferSize(sampleRateInHz,channelConfig,audioFormat);
        if (mMinBufferSize == AudioTrack.ERROR_BAD_VALUE) {
    
    
            Log.e(TAG, "Invalid parameter !");
            return false;
        }
        Log.d(TAG , "getMinBufferSize = "+mMinBufferSize+" bytes !");
        
        mAudioTrack = new AudioTrack(streamType,sampleRateInHz,channelConfig,audioFormat,mMinBufferSize,DEFAULT_PLAY_MODE);
        if (mAudioTrack.getState() == AudioTrack.STATE_UNINITIALIZED) {
    
    
            Log.e(TAG, "AudioTrack initialize fail !");
            return false;
        }            
        
        mIsPlayStarted = true;
        
        Log.d(TAG, "Start audio player success !");
        
        return true;
    }
    
    public int getMinBufferSize() {
    
    
        return mMinBufferSize;
    }
    
    public void stopPlayer() {
    
    
        
        if (!mIsPlayStarted) {
    
    
            return;
        }
        
        if (mAudioTrack.getPlayState() == AudioTrack.PLAYSTATE_PLAYING) {
    
    
            mAudioTrack.stop();                        
        }
        
        mAudioTrack.release();
        mIsPlayStarted = false;
           
        Log.d(TAG, "Stop audio player success !");
    }
    
    public boolean play(byte[] audioData, int offsetInBytes, int sizeInBytes) {
    
    
        
        if (!mIsPlayStarted) {
    
    
            Log.e(TAG, "Player not started !");
            return false;
        }
        
        if (sizeInBytes < mMinBufferSize) {
    
    
            Log.e(TAG, "audio data is not enough !");
            return false;
        }
        
        if (mAudioTrack.write(audioData,offsetInBytes,sizeInBytes) != sizeInBytes) {
    
                    
            Log.e(TAG, "Could not write all the samples to the audio device !");
        }                                   
                                                   
        mAudioTrack.play();
        
        Log.d(TAG , "OK, Played "+sizeInBytes+" bytes !");
        
        return true;
    }
}

六、参考

觉得好，就一键三连呗（点赞+收藏+关注）

Android 使用外置USB麦克风MIC录音遇到问题并解决（含录音播放源码）

文章目录

一、遇到问题

二、分析问题

三、解决问题

四、录音源码分析

五、播放源码分析

六、参考

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