Android write PCM byte array to wav file

Question

I am trying to convert PCM 16 bit with Sampling rate 8000, single channel to wav file.

below is code :

private void rawToWaveafterUpload(final File rawFile, final File waveFile) throws IOException {

        byte[] rawData = new byte[(int) rawFile.length()];
        DataInputStream input = null;
        if(rawFile.exists()) {

            try {
                FileInputStream rawFileInputStream = new FileInputStream(rawFile);
                input = new DataInputStream(rawFileInputStream);
                input.read(rawData);

            } catch (Exception e) {

            } finally {
                if (input != null) {
                    input.close();
                }
            }

            DataOutputStream output = null;
            try {
                output = new DataOutputStream(new FileOutputStream(waveFile));
                // WAVE header
                writeString(output, "RIFF"); // chunk id
                writeInt(output, 36 + rawData.length); // chunk size
                writeString(output, "WAVE"); // format
                writeString(output, "fmt "); // subchunk 1 id
                writeInt(output, 16); // subchunk 1 size
                writeShort(output, (short) 1); // audio format (1 = PCM)
                writeShort(output, (short) 1); // number of channels
                writeInt(output, 8000); // sample rate
                writeInt(output, 8000 * 2); // byte rate
                writeShort(output, (short) 2); // block align
                writeShort(output, (short) 16); // bits per sample
                writeString(output, "data"); // subchunk 2 id
                writeInt(output, rawData.length); // subchunk 2 size
                // Audio data (conversion big endian -> little endian)
                short[] shorts = new short[rawData.length / 2];
                ByteBuffer.wrap(rawData).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer().get(shorts);
                ByteBuffer bytes = ByteBuffer.allocate(shorts.length * 2);
                for (short s : shorts) {
                    bytes.putShort(s);
                }
                output.write(bytes.array());
            } finally {
                if (output != null) {
                    output.close();
                    //rawFile.delete();
                }
            }

        }}


    private void writeInt(final DataOutputStream output, final int value) throws IOException {
        output.write(value >> 0);
        output.write(value >> 8);
        output.write(value >> 16);
        output.write(value >> 24);
    }

    private void writeShort(final DataOutputStream output, final short value) throws IOException {
        output.write(value >> 0);
        output.write(value >> 8);
    }

    private void writeString(final DataOutputStream output, final String value) throws IOException {
        for (int i = 0; i < value.length(); i++) {
            output.write(value.charAt(i));
        }
    }

When i play my pcm from PCM player App the audio is playing fine. but i am not able to convert this audio to wav file. Audio is not getting played. below is PCM file which i need to convert to wave

Answer 1

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;



public class PCmTowav {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        File read = new File("left_1.pcm");

        File out = new File("left.wav");
        try {
            PCMToWAV(read, out, 1, 8000, 16);

        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    /*
     * static public void PCMToWAV(File input, File output, AudioFormat format)
     * throws IOException { int bitsPerSample; switch (format.getEncoding()) { case
     * AudioFormat.ENCODING_PCM_8BIT: bitsPerSample = 8; break; case
     * AudioFormat.ENCODING_PCM_FLOAT: bitsPerSample = 32; break; case
     * AudioFormat.ENCODING_PCM_16BIT: default: bitsPerSample = 16;
     * 
     * } }
     */

    /**
     * @param input         raw PCM data
     *                      limit of file size for wave file: < 2^(2*4) - 36 bytes (~4GB)
     * @param output        file to encode to in wav format
     * @param channelCount  number of channels: 1 for mono, 2 for stereo, etc.
     * @param sampleRate    sample rate of PCM audio
     * @param bitsPerSample bits per sample, i.e. 16 for PCM16
     * @throws IOException in event of an error between input/output files
     * @see <a href="http://soundfile.sapp.org/doc/WaveFormat/">soundfile.sapp.org/doc/WaveFormat</a>
     */
    static public void PCMToWAV(File input, File output, int channelCount, int sampleRate, int bitsPerSample) throws IOException {
        final int inputSize = (int) input.length();

        try {
            OutputStream encoded = new FileOutputStream(output);
            // WAVE RIFF header
            writeToOutput(encoded, "RIFF"); // chunk id
            writeToOutput(encoded, 36 + inputSize); // chunk size
            writeToOutput(encoded, "WAVE"); // format

            // SUB CHUNK 1 (FORMAT)
            writeToOutput(encoded, "fmt "); // subchunk 1 id
            writeToOutput(encoded, 16); // subchunk 1 size
            writeToOutput(encoded, (short) 1); // audio format (1 = PCM)
            writeToOutput(encoded, (short) channelCount); // number of channelCount
            writeToOutput(encoded, sampleRate); // sample rate
            writeToOutput(encoded, sampleRate * channelCount * bitsPerSample / 8); // byte rate
            writeToOutput(encoded, (short) (channelCount * bitsPerSample / 8)); // block align
            writeToOutput(encoded, (short) bitsPerSample); // bits per sample

            // SUB CHUNK 2 (AUDIO DATA)
            writeToOutput(encoded, "data"); // subchunk 2 id
            writeToOutput(encoded, inputSize); // subchunk 2 size
            copy(new FileInputStream(input), encoded);
        }catch(Exception e) {

        }
    }


    /**
     * Size of buffer used for transfer, by default
     */
    private static final int TRANSFER_BUFFER_SIZE = 10 * 1024;

    /**
     * Writes string in big endian form to an output stream
     *
     * @param output stream
     * @param data   string
     * @throws IOException
     */
    public static void writeToOutput(OutputStream output, String data) throws IOException {
        for (int i = 0; i < data.length(); i++)
            output.write(data.charAt(i));
    }

    public static void writeToOutput(OutputStream output, int data) throws IOException {
        output.write(data >> 0);
        output.write(data >> 8);
        output.write(data >> 16);
        output.write(data >> 24);
    }

    public static void writeToOutput(OutputStream output, short data) throws IOException {
        output.write(data >> 0);
        output.write(data >> 8);
    }

    public static long copy(InputStream source, OutputStream output)
            throws IOException {
        return copy(source, output, TRANSFER_BUFFER_SIZE);
    }

    public static long copy(InputStream source, OutputStream output, int bufferSize) throws IOException {
        long read = 0L;
        byte[] buffer = new byte[bufferSize];
        for (int n; (n = source.read(buffer)) != -1; read += n) {
            output.write(buffer, 0, n);
        }
        return read;
    }

}