Android concat 2 audio (wav or mp3) files

Question

I must concat 2 or more audio (wav or mp3) files and get one audio file. How can I do that in android? Thanks in advance.

Answer 1

The below code section will work as how many selections have been made.Selection means how much files are selected. Put your two wav files in /sdcard0/SSoftAudioFiles/ as 1.wav and 2.wav. And Just execute this method.

public void SSoftAudCombine()
{
 try {
String[] selection=new String[2];
selection[0]="1.wav";
selection[1]="2.wav";
            DataOutputStream amplifyOutputStream = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(Environment.getExternalStorageDirectory() + "/SSoftAudioFiles/"  + year +"-"+ month +"-"+ date +"-"+ hour+"-" + min +"-"+ sec+"ME.wav")));
            DataInputStream[] mergeFilesStream = new DataInputStream[selection.length];
            long[] sizes=new long[selection.length];
            for(int i=0; i<selection.length; i++) {
                File file = new File(Environment.getExternalStorageDirectory() + "/SSoftAudioFiles/" +selection[i]);
             sizes[i] = (file.length()-44)/2;
            }
            for(int i =0; i<selection.length; i++) {
                mergeFilesStream[i] =new DataInputStream(new BufferedInputStream(new FileInputStream(Environment.getExternalStorageDirectory() + "/SSoftAudioFiles/" +selection[i])));

                if(i == selection.length-1) {
                    mergeFilesStream[i].skip(24);
                    byte[] sampleRt = new byte[4];
                    mergeFilesStream[i].read(sampleRt);
                    ByteBuffer bbInt = ByteBuffer.wrap(sampleRt).order(ByteOrder.LITTLE_ENDIAN);
                    RECORDER_SAMPLERATE = bbInt.getInt();
                    mergeFilesStream[i].skip(16);
                }
                    else {
                        mergeFilesStream[i].skip(44);
                    }

            }

            for(int b=0; b<selection.length; b++) {
            for(int i=0; i<(int)sizes[b]; i++) {
                 byte[] dataBytes = new byte[2];
                 try {
                 dataBytes[0] = mergeFilesStream[b].readByte();
                 dataBytes[1] = mergeFilesStream[b].readByte();
                 }
                 catch (EOFException e) {
                    amplifyOutputStream.close();
                 }
                 short dataInShort = ByteBuffer.wrap(dataBytes).order(ByteOrder.LITTLE_ENDIAN).getShort();
                 float dataInFloat= (float) dataInShort/37268.0f;


                short outputSample = (short)(dataInFloat * 37268.0f);
                byte[] dataFin = new byte[2];
               dataFin[0] = (byte) (outputSample & 0xff);
               dataFin[1] = (byte)((outputSample >> 8) & 0xff);        
              amplifyOutputStream.write(dataFin, 0 , 2);

            }
            }
            amplifyOutputStream.close();
            for(int i=0; i<selection.length; i++) {
                mergeFilesStream[i].close();
            }

        } catch (FileNotFoundException e) {

            e.printStackTrace();
        } catch (IOException e) {

            e.printStackTrace();
        }
        long size =0;
        try {
            FileInputStream fileSize = new FileInputStream(Environment.getExternalStorageDirectory() + "/SSoftAudioFiles/"+year +"-"+ month +"-"+ date +"-"+ hour+"-" + min +"-"+ sec+"ME.wav");
            size = fileSize.getChannel().size();
            fileSize.close();
        } catch (FileNotFoundException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


        final int RECORDER_BPP = 16;

        long datasize=size+36;
        long byteRate = (RECORDER_BPP * RECORDER_SAMPLERATE)/8;
        long longSampleRate = RECORDER_SAMPLERATE;
        byte[] header = new byte[44];


         header[0] = 'R';  // RIFF/WAVE header 
         header[1] = 'I';
         header[2] = 'F';
         header[3] = 'F';
         header[4] = (byte) (datasize & 0xff);
         header[5] = (byte) ((datasize >> 8) & 0xff);
         header[6] = (byte) ((datasize >> 16) & 0xff);
         header[7] = (byte) ((datasize >> 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) 1;
         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) ((RECORDER_BPP) / 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) (size & 0xff);
         header[41] = (byte) ((size >> 8) & 0xff);
         header[42] = (byte) ((size >> 16) & 0xff);
         header[43] = (byte) ((size >> 24) & 0xff);
       // out.write(header, 0, 44); 

        try {
             RandomAccessFile rFile = new RandomAccessFile(Environment.getExternalStorageDirectory() + "/SSoftAudioFiles/"  +year +"-"+ month +"-"+ date +"-"+ hour+"-" + min +"-"+ sec+ "ME.wav", "rw");
            rFile.seek(0);
            rFile.write(header);
            rFile.close();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
}

It will concate your audio file and save a combined file in /sdcard0/SSoftAudioFiles/...ME.wav.