After a lot of research, I can't find a clear answer. What I want to achieve is: take an mp3/wav file and save its left and right channels to 2 byte[]. Then I can manipulate each channel and then add them up again and create a new wav file. (preferably the solution to be in Java)
Related question is split two channels of AudioRecord of CHANNEL_IN_STEREO. However this is using audiorecord, how to apply it to reading from audio file?
Thanks
Well here is the program to read a 16 bit wave file
Sample Audio: http://freewavesamples.com/korg-triton-slow-choir-st-c4
Data Packing for 16-Bit Stereo PCM:
Sample 1
Channel 0 | Channel 0 | Channel 1 | Channel 1
(left) | (left) | (right) | (right)
low-order | high-order | low-order | high-order
byte | byte | byte | byte
And printing it in CSV format. I will not put the CSV writer code here. Its already available here.
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.UnsupportedEncodingException;
public class AudioReader {
class WavHeader {
public byte[] RIFF_ID = new byte[4]; // "riff"
public int SIZE; //
public byte[] WAV_ID = new byte[4]; // "WAVE"
public byte[] FMT_ID = new byte[4]; // "fmt id"
public int FMT_SZ; // fmt
public int FORMAT; //
public short CHANNELS; // Channels
public int SAMPLE_PER_SEC; // Sample per second
public int AVGBYTE_PER_SEC; // Average Byte per second
public short BLOCK_SZ; // CHANNELS * (BIT>>3)
public short BIT; // BITS
public byte[] DATA_ID = new byte[4]; // "data"
public int DATA_SZ; //
}
String m_strFileName;
WavHeader m_objHeader;
public AudioReader(String strFileName) {
m_strFileName = strFileName;
m_objHeader = new WavHeader();
}
private void printHeaderBigEndian(int nSamples) {
try {
// 1
String str1 = new String(m_objHeader.RIFF_ID, "ISO-8859-1");
System.out.println("Riff Id: " + str1);
// 2
System.out.println("Size: " + m_objHeader.SIZE);
// 3
String str2 = new String(m_objHeader.WAV_ID, "ISO-8859-1");
System.out.println("Wav Id: " + str2);
// 3
String str3 = new String(m_objHeader.FMT_ID, "ISO-8859-1");
System.out.println("Fmt Id: " + str3);
// 4
System.out.println("Format: " + m_objHeader.FORMAT);
// 5
System.out.println("Channels: " + m_objHeader.CHANNELS);
// 6
System.out.println("Sample per sec: " + m_objHeader.SAMPLE_PER_SEC);
// 7
System.out.println("Avg Byte per sec: "
+ m_objHeader.AVGBYTE_PER_SEC);
// 8
System.out.println("Block Sz: " + m_objHeader.BLOCK_SZ);
// 9
System.out.println("Bit: " + m_objHeader.BIT);
// 10
String str4 = new String(m_objHeader.DATA_ID, "ISO-8859-1");
System.out.println("Data Id: " + str4);
// 11
System.out.println("Data Sz: " + m_objHeader.DATA_SZ);
// 12
System.out.println("Samples: " + nSamples);
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// ////////////////////////////////////////////////////////////////////////////////////
//
public void ReadUsingDataInputStream() {
try {
File in = new File(m_strFileName);
FileInputStream fis = new FileInputStream(in);
DataInputStream dis = new DataInputStream(fis);
dis.read(m_objHeader.RIFF_ID, 0, 4);
m_objHeader.SIZE = Integer.reverseBytes(dis.readInt());
dis.read(m_objHeader.WAV_ID, 0, 4);
dis.read(m_objHeader.FMT_ID, 0, 4);
m_objHeader.FMT_SZ = Integer.reverseBytes(dis.readInt());
m_objHeader.FORMAT = Short.reverseBytes(dis.readShort());
m_objHeader.CHANNELS = Short.reverseBytes(dis.readShort());
m_objHeader.SAMPLE_PER_SEC = Integer.reverseBytes(dis.readInt());
m_objHeader.AVGBYTE_PER_SEC = Integer.reverseBytes(dis.readInt());
m_objHeader.BLOCK_SZ = Short.reverseBytes(dis.readShort());
m_objHeader.BIT = Short.reverseBytes(dis.readShort());
dis.read(m_objHeader.DATA_ID, 0, 4);
m_objHeader.DATA_SZ = Integer.reverseBytes(dis.readInt());
int nSamples = m_objHeader.DATA_SZ / m_objHeader.BLOCK_SZ;
printHeaderBigEndian(nSamples);
String strCsvFileName = in.getParent() + "//" + in.getName()
+ ".csv";
String strLine[] = new String[3];
File out = new File(strCsvFileName);
out.createNewFile();
FileWriter fw = new FileWriter(out);
CSVWriter csvW = new CSVWriter(fw);
for (int n = 1; n < nSamples; n++) {
strLine[0] = Integer.toString(n);
strLine[1] = Short.toString(Short.reverseBytes(dis.readShort()));
strLine[2] = Short.toString(Short.reverseBytes(dis.readShort()));
csvW.writeNext(strLine);
}
dis.close();
csvW.Close();
System.out.println("Done.....");
} catch (Exception e) {
e.printStackTrace();
}
}
}