/**
* This function goes through all samples of the .WAV song and multiplies the values by the given
* gainFactor in order to achieve the volume changing
*
* @param gainFactor - the value which is multiplied with the sample value to get new sample value
*/
public void changeVolume(double gainFactor) {
int sample = 0;
for (int i = wavTagReader.getFirstSampleIndex(); i < rawData.length - 2; i = i + 2) {
sample = (short) rawData[i] + (short) ((rawData[i + 1] << 8) & 0xFF00);
sample *= gainFactor;
rawData[i] = (byte) (sample & 0xFF);
rawData[i + 1] = (byte) ((sample >>> 8) & 0xFF);
}
}
/**
* This function is responsible for muting the fragment of the currently edited .WAV song.
*
* @param startSecond - the start time from which the song is cutted
* @param endSecond - the end time to which the song is cutted
*/
public void muteSong(int startSecond, int endSecond) {
int startIndex =
wavTagReader.getFirstSampleIndex()
+ startSecond
* wavTagReader.sampleRate
* wavTagReader.numOfChannels
* wavTagReader.bitsPerSample
/ 8;
int endIndex =
wavTagReader.getFirstSampleIndex()
+ endSecond
* wavTagReader.sampleRate
* wavTagReader.numOfChannels
* wavTagReader.bitsPerSample
/ 8;
for (int i = startIndex; i < endIndex; i++) rawData[i] = 0;
}
/**
* This function cuts the fragment of song, and puts it in another byte array. It assigns also the
* header of the edited song to the cut fragment
*
* @param startSecond - the start second to cut
* @param endSecond - the end second to cut
* @return reference to the array with cut fragment.
*/
public byte[] cutSong(int startSecond, int endSecond) {
int startIndex =
wavTagReader.getFirstSampleIndex()
+ startSecond
* wavTagReader.sampleRate
* wavTagReader.numOfChannels
* wavTagReader.bitsPerSample
/ 8;
int endIndex =
wavTagReader.getFirstSampleIndex()
+ endSecond
* wavTagReader.sampleRate
* wavTagReader.numOfChannels
* wavTagReader.bitsPerSample
/ 8;
byte cutSong[] = new byte[wavTagReader.getFirstSampleIndex() + (endIndex - startIndex)];
/// Copy the song header except for data field size
for (int i = 0; i < wavTagReader.getFirstSampleIndex() - 4; i++) {
cutSong[i] = rawData[i];
}
/// Set the new data size
int samplesSize = endIndex - startIndex;
int firstSampleIndex = wavTagReader.getFirstSampleIndex();
for (int i = 0; i < 4; i++) {
cutSong[firstSampleIndex - 4 + i] = (byte) ((samplesSize >>> (i * 8)) & 0xFF);
}
int byteIndex = startIndex;
/// Copy the data
for (int i = wavTagReader.getFirstSampleIndex(); i < cutSong.length; i++) {
cutSong[i] = rawData[byteIndex++];
}
return cutSong;
}