Question

我有一个记录音频的简单应用程序。起初，我使用MediaRecorder。但问题是我无法记录WAVE。（或者是否可以使用MediaRecorder进行录制并且具有带标题的WAV输出？）。所以我跟着example：

        public class MainActivity extends Activity {


            private static final int RECORDER_BPP = 16;
            private static final String AUDIO_RECORDER_FILE_EXT_WAV = ".wav";
            private static final String AUDIO_RECORDER_FOLDER = "AudioRecorder";
            private static final String AUDIO_RECORDER_TEMP_FILE = "record_temp.raw";
            private static final int RECORDER_SAMPLERATE = 48000;
            private static final int RECORDER_CHANNELS = AudioFormat.CHANNEL_IN_STEREO;
            private static final int RECORDER_AUDIO_ENCODING = AudioFormat.ENCODING_PCM_16BIT;

            MediaPlayer media = null;
            private AudioRecord recorder = null;
            private int bufferSize = 0;
            private Thread recordingThread = null;
            private boolean isRecording = false;

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            setButtonHandlers();
            enableButtons(false);

            bufferSize = AudioRecord.getMinBufferSize(441000,
                    AudioFormat.CHANNEL_IN_STEREO,
                    AudioFormat.ENCODING_PCM_16BIT);

            System.out.println("buffer size: " + bufferSize);
        }

        private void setButtonHandlers() {
                ((Button)findViewById(R.id.btnStart)).setOnClickListener(btnClick);
        ((Button)findViewById(R.id.btnStop)).setOnClickListener(btnClick);
        }



        private void enableButton(int id,boolean isEnable){
                ((Button)findViewById(id)).setEnabled(isEnable);
        }



        private void enableButtons(boolean isRecording) {
                enableButton(R.id.btnStart,!isRecording);
                enableButton(R.id.btnStop,isRecording);
        }



        private String getFilename(){
                String filepath = Environment.getExternalStorageDirectory().getPath();
                File file = new File(filepath,AUDIO_RECORDER_FOLDER);

                if(!file.exists()){
                        file.mkdirs();
                }

                return (file.getAbsolutePath() + "/" + System.currentTimeMillis() + AUDIO_RECORDER_FILE_EXT_WAV);
        }



        private String getTempFilename(){
                String filepath = Environment.getExternalStorageDirectory().getPath();
                File file = new File(filepath,AUDIO_RECORDER_FOLDER);

                if(!file.exists()){
                        file.mkdirs();
                }

                File tempFile = new File(filepath,AUDIO_RECORDER_TEMP_FILE);

                if(tempFile.exists())
                        tempFile.delete();

                return (file.getAbsolutePath() + "/" + AUDIO_RECORDER_TEMP_FILE);
        }



        private void startRecording(){
                recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
                                                RECORDER_SAMPLERATE, RECORDER_CHANNELS,RECORDER_AUDIO_ENCODING, bufferSize);
                int i = recorder.getState();
                if(i==1)
                    recorder.startRecording();

                isRecording = true;

                recordingThread = new Thread(new Runnable() {

                        @Override
                        public void run() {
                                writeAudioDataToFile();

                        }
                },"AudioRecorder Thread");

                recordingThread.start();

        }



        private void writeAudioDataToFile(){
                byte data[] = new byte[bufferSize];
                String filename = getTempFilename();
                FileOutputStream os = null;

                try {
                        os = new FileOutputStream(filename);
                } catch (FileNotFoundException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                }

                int read = 0;

                if(null != os){
                        while(isRecording){
                                read = recorder.read(data, 0, bufferSize);

                                if(AudioRecord.ERROR_INVALID_OPERATION != read){
                                        try {
                                                os.write(data);
                                        } catch (IOException e) {
                                                e.printStackTrace();
                                        }
                                }
                        }

                        try {
                                os.close();
                        } catch (IOException e) {
                                e.printStackTrace();
                        }
                }
        }


        private void stopRecording(){
                if(null != recorder){
                        isRecording = false;

                        int i = recorder.getState();
                        if(i==1)
                            recorder.stop();
                        recorder.release();

                        recorder = null;
                        recordingThread = null;
                }

                if(media != null) media.stop();
                copyWaveFile(getTempFilename(),getFilename());
                deleteTempFile();
        }

        private void deleteTempFile() {
                File file = new File(getTempFilename());

                file.delete();
        }

        private void copyWaveFile(String inFilename,String outFilename){
                FileInputStream in = null;
                FileOutputStream out = null;
                long totalAudioLen = 0;
                long totalDataLen = totalAudioLen + 36;
                long longSampleRate = RECORDER_SAMPLERATE;
                int channels = 2;
                long byteRate = RECORDER_BPP * RECORDER_SAMPLERATE * channels/8;

                byte[] data = new byte[bufferSize];

                try {
                        in = new FileInputStream(inFilename);
                        out = new FileOutputStream(outFilename);
                        totalAudioLen = in.getChannel().size();
                        totalDataLen = totalAudioLen + 36;

                        AppLog.logString("File size: " + totalDataLen);

                        WriteWaveFileHeader(out, totalAudioLen, totalDataLen,
                                        longSampleRate, channels, byteRate);

                        while(in.read(data) != -1){
                                out.write(data);
                        }

                        in.close();
                        out.close();
                } catch (FileNotFoundException e) {
                        e.printStackTrace();
                } catch (IOException e) {
                        e.printStackTrace();
                }
        }

        private void WriteWaveFileHeader(
                        FileOutputStream out, long totalAudioLen,
                        long totalDataLen, long longSampleRate, int channels,
                        long byteRate) throws IOException {

                byte[] header = new byte[44];

                header[0] = 'R';  // RIFF/WAVE header
                header[1] = 'I';
                header[2] = 'F';
                header[3] = 'F';
                header[4] = (byte) (totalDataLen & 0xff);
                header[5] = (byte) ((totalDataLen >> 8) & 0xff);
                header[6] = (byte) ((totalDataLen >> 16) & 0xff);
                header[7] = (byte) ((totalDataLen >> 24) & 0xff);
                header[8] = 'W';
                header[9] = 'A';
                header[10] = 'V';
                header[11] = 'E';
                header[12] = 'f';  // 'fmt ' chunk
                header[13] = 'm';
                header[14] = 't';
                header[15] = ' ';
                header[16] = 16;  // 4 bytes: size of 'fmt ' chunk
                header[17] = 0;
                header[18] = 0;
                header[19] = 0;
                header[20] = 1;  // format = 1
                header[21] = 0;
                header[22] = (byte) channels;
                header[23] = 0;
                header[24] = (byte) (longSampleRate & 0xff);
                header[25] = (byte) ((longSampleRate >> 8) & 0xff);
                header[26] = (byte) ((longSampleRate >> 16) & 0xff);
                header[27] = (byte) ((longSampleRate >> 24) & 0xff);
                header[28] = (byte) (byteRate & 0xff);
                header[29] = (byte) ((byteRate >> 8) & 0xff);
                header[30] = (byte) ((byteRate >> 16) & 0xff);
                header[31] = (byte) ((byteRate >> 24) & 0xff);
                header[32] = (byte) (2 * 16 / 8);  // block align
                header[33] = 0;
                header[34] = RECORDER_BPP;  // bits per sample
                header[35] = 0;
                header[36] = 'd';
                header[37] = 'a';
                header[38] = 't';
                header[39] = 'a';
                header[40] = (byte) (totalAudioLen & 0xff);
                header[41] = (byte) ((totalAudioLen >> 8) & 0xff);
                header[42] = (byte) ((totalAudioLen >> 16) & 0xff);
                header[43] = (byte) ((totalAudioLen >> 24) & 0xff);

                out.write(header, 0, 44);
        }

        private View.OnClickListener btnClick = new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                        switch(v.getId()){
                                case R.id.btnStart:{
                                        AppLog.logString("Start Recording");

                                        enableButtons(true);
                                        startRecording();

                                        break;
                                }
                                case R.id.btnStop:{
                                        AppLog.logString("Start Recording");

                                            enableButtons(false);
                                            stopRecording();

                                            break;
                                    }
                            }
                    }
            }; 
        }

但是当我录制一个节拍器时，我注意到了一个不规则的情况。看一下波形，就像这样......

enter image description here

可能出了什么问题？

非常感谢您的帮助。

[附加]

在其他情况下：这就是发生的事情：

enter image description here

我不知道在特定时间录音发生了什么，绿圈内的录音。当时录音机是否停止然后再次启动？

Answer 1

我认为AudioRecord.getMinBufferSize（441000，...应该是44100而不是410000

Android- AudioRecord在录制时有一些跳过节拍

1 个答案: