package urbanstew.RehearsalAssistant;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.util.Log;
public class RehearsalAudioRecorder
{
/**
* INITIALIZING : recorder is initializing;
* READY : recorder has been initialized, recorder not yet started
* RECORDING : recording
* ERROR : reconstruction needed
* STOPPED: reset needed
*/
public enum State {INITIALIZING, READY, RECORDING, ERROR, STOPPED};
public static final boolean RECORDING_UNCOMPRESSED = true;
public static final boolean RECORDING_COMPRESSED = false;
// The interval in which the recorded samples are output to the file
// Used only in uncompressed mode
private static final int TIMER_INTERVAL = 120;
// Toggles uncompressed recording on/off; RECORDING_UNCOMPRESSED / RECORDING_COMPRESSED
private boolean rUncompressed;
// Recorder used for uncompressed recording
private AudioRecord aRecorder = null;
// Recorder used for compressed recording
private MediaRecorder mRecorder = null;
// Stores current amplitude (only in uncompressed mode)
private int cAmplitude= 0;
// Output file path
private String fPath = null;
// Recorder state; see State
private State state;
// File writer (only in uncompressed mode)
private RandomAccessFile fWriter;
// Number of channels, sample rate, sample size(size in bits), buffer size, audio source, sample size(see AudioFormat)
private short nChannels;
private int sRate;
private short bSamples;
private int bufferSize;
private int aSource;
private int aFormat;
// Number of frames written to file on each output(only in uncompressed mode)
private int framePeriod;
// Buffer for output(only in uncompressed mode)
private byte[] buffer;
// Number of bytes written to file after header(only in uncompressed mode)
// after stop() is called, this size is written to the header/data chunk in the wave file
private int payloadSize;
/**
*
* Returns the state of the recorder in a RehearsalAudioRecord.State typed object.
* Useful, as no exceptions are thrown.
*
* @return recorder state
*/
public State getState()
{
return state;
}
/*
*
* Method used for recording.
*
*/
private AudioRecord.OnRecordPositionUpdateListener updateListener = new AudioRecord.OnRecordPositionUpdateListener()
{
@Override
public void onPeriodicNotification(AudioRecord recorder)
{
aRecorder.read(buffer, 0, buffer.length); // Fill buffer
try
{
fWriter.write(buffer); // Write buffer to file
payloadSize += buffer.length;
if (bSamples == 16)
{
for (int i=0; i<buffer.length/2; i++)
{ // 16bit sample size
short curSample = getShort(buffer[i*2], buffer[i*2+1]);
if (curSample > cAmplitude)
{ // Check amplitude
cAmplitude = curSample;
}
}
}
else
{ // 8bit sample size
for (int i=0; i<buffer.length; i++)
{
if (buffer[i] > cAmplitude)
{ // Check amplitude
cAmplitude = buffer[i];
}
}
}
}
catch (IOException e)
{
Log.e(RehearsalAudioRecorder.class.getName(), "Error occured in updateListener, recording is aborted");
stop();
}
}
@Override
public void onMarkerReached(AudioRecord recorder)
{
// NOT USED
}
};
/**
*
*
* Default constructor
*
* Instantiates a new recorder, in case of compressed recording the parameters can be left as 0.
* In case of errors, no exception is thrown, but the state is set to ERROR
*
*/
public RehearsalAudioRecorder(boolean uncompressed, int audioSource, int sampleRate, int channelConfig,
int audioFormat)
{
try
{
rUncompressed = uncompressed;
if (rUncompressed)
{ // RECORDING_UNCOMPRESSED
if (audioFormat == AudioFormat.ENCODING_PCM_16BIT)
{
bSamples = 16;
}
else
{
bSamples = 8;
}
if (channelConfig == AudioFormat.CHANNEL_CONFIGURATION_MONO)
{
nChannels = 1;
}
else
{
nChannels = 2;
}
aSource = audioSource;
sRate = sampleRate;
aFormat = audioFormat;
framePeriod = sampleRate * TIMER_INTERVAL / 1000;
bufferSize = framePeriod * 2 * bSamples * nChannels / 8;
if (bufferSize < AudioRecord.getMinBufferSize(sampleRate, channelConfig, audioFormat))
{ // Check to make sure buffer size is not smaller than the smallest allowed one
bufferSize = AudioRecord.getMinBufferSize(sampleRate, channelConfig, audioFormat);
// Set frame period and timer interval accordingly
framePeriod = bufferSize / ( 2 * bSamples * nChannels / 8 );
Log.w(RehearsalAudioRecorder.class.getName(), "Increasing buffer size to " + Integer.toString(bufferSize));
}
aRecorder = new AudioRecord(audioSource, sampleRate, channelConfig, audioFormat, bufferSize);
if (aRecorder.getState() != AudioRecord.STATE_INITIALIZED)
throw new Exception("AudioRecord initialization failed");
aRecorder.setRecordPositionUpdateListener(updateListener);
aRecorder.setPositionNotificationPeriod(framePeriod);
} else
{ // RECORDING_COMPRESSED
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
}
cAmplitude = 0;
fPath = null;
state = State.INITIALIZING;
} catch (Exception e)
{
if (e.getMessage() != null)
{
Log.e(RehearsalAudioRecorder.class.getName(), e.getMessage());
}
else
{
Log.e(RehearsalAudioRecorder.class.getName(), "Unknown error occured while initializing recording");
}
state = State.ERROR;
}
}
/**
* Sets output file path, call directly after construction/reset.
*
* @param output file path
*
*/
public void setOutputFile(String argPath)
{
try
{
if (state == State.INITIALIZING)
{
fPath = argPath;
if (!rUncompressed)
{
mRecorder.setOutputFile(fPath);
}
}
}
catch (Exception e)
{
if (e.getMessage() != null)
{
Log.e(RehearsalAudioRecorder.class.getName(), e.getMessage());
}
else
{
Log.e(RehearsalAudioRecorder.class.getName(), "Unknown error occured while setting output path");
}
state = State.ERROR;
}
}
/**
*
* Returns the largest amplitude sampled since the last call to this method.
*
* @return returns the largest amplitude since the last call, or 0 when not in recording state.
*
*/
public int getMaxAmplitude()
{
if (state == State.RECORDING)
{
if (rUncompressed)
{
int result = cAmplitude;
cAmplitude = 0;
return result;
}
else
{
try
{
return mRecorder.getMaxAmplitude();
}
catch (IllegalStateException e)
{
return 0;
}
}
}
else
{
return 0;
}
}
/**
*
* Prepares the recorder for recording, in case the recorder is not in the INITIALIZING state and the file path was not set
* the recorder is set to the ERROR state, which makes a reconstruction necessary.
* In case uncompressed recording is toggled, the header of the wave file is written.
* In case of an exception, the state is changed to ERROR
*
*/
public void prepare()
{
try
{
if (state == State.INITIALIZING)
{
if (rUncompressed)
{
if ((aRecorder.getState() == AudioRecord.STATE_INITIALIZED) & (fPath != null))
{
// write file header
fWriter = new RandomAccessFile(fPath, "rw");
fWriter.setLength(0); // Set file length to 0, to prevent unexpected behavior in case the file already existed
fWriter.writeBytes("RIFF");
fWriter.writeInt(0); // Final file size not known yet, write 0
fWriter.writeBytes("WAVE");
fWriter.writeBytes("fmt ");
fWriter.writeInt(Integer.reverseBytes(16)); // Sub-chunk size, 16 for PCM
fWriter.writeShort(Short.reverseBytes((short) 1)); // AudioFormat, 1 for PCM
fWriter.writeShort(Short.reverseBytes(nChannels));// Number of channels, 1 for mono, 2 for stereo
fWriter.writeInt(Integer.reverseBytes(sRate)); // Sample rate
fWriter.writeInt(Integer.reverseBytes(sRate*bSamples*nChannels/8)); // Byte rate, SampleRate*NumberOfChannels*BitsPerSample/8
fWriter.writeShort(Short.reverseBytes((short)(nChannels*bSamples/8))); // Block align, NumberOfChannels*BitsPerSample/8
fWriter.writeShort(Short.reverseBytes(bSamples)); // Bits per sample
fWriter.writeBytes("data");
fWriter.writeInt(0); // Data chunk size not known yet, write 0
buffer = new byte[framePeriod*bSamples/8*nChannels];
state = State.READY;
}
else
{
Log.e(RehearsalAudioRecorder.class.getName(), "prepare() method called on uninitialized recorder");
state = State.ERROR;
}
}
else
{
mRecorder.prepare();
state = State.READY;
}
}
else
{
Log.e(RehearsalAudioRecorder.class.getName(), "prepare() method called on illegal state");
release();
state = State.ERROR;
}
}
catch(Exception e)
{
if (e.getMessage() != null)
{
Log.e(RehearsalAudioRecorder.class.getName(), e.getMessage());
}
else
{
Log.e(RehearsalAudioRecorder.class.getName(), "Unknown error occured in prepare()");
}
state = State.ERROR;
}
}
/**
*
* Releases the resources associated with this class, and removes the unnecessary files, when necessary
*
*/
public void release()
{
if (state == State.RECORDING)
{
stop();
}
else
{
if ((state == State.READY) & (rUncompressed))
{
try
{
fWriter.close(); // Remove prepared file
}
catch (IOException e)
{
Log.e(RehearsalAudioRecorder.class.getName(), "I/O exception occured while closing output file");
}
(new File(fPath)).delete();
}
}
if (rUncompressed)
{
if (aRecorder != null)
{
aRecorder.release();
}
}
else
{
if (mRecorder != null)
{
mRecorder.release();
}
}
}
/**
*
*
* Resets the recorder to the INITIALIZING state, as if it was just created.
* In case the class was in RECORDING state, the recording is stopped.
* In case of exceptions the class is set to the ERROR state.
*
*/
public void reset()
{
try
{
if (state != State.ERROR)
{
release();
fPath = null; // Reset file path
cAmplitude = 0; // Reset amplitude
if (rUncompressed)
{
aRecorder = new AudioRecord(aSource, sRate, nChannels+1, aFormat, bufferSize);
}
else
{
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
}
state = State.INITIALIZING;
}
}
catch (Exception e)
{
Log.e(RehearsalAudioRecorder.class.getName(), e.getMessage());
state = State.ERROR;
}
}
/**
*
*
* Starts the recording, and sets the state to RECORDING.
* Call after prepare().
*
*/
public void start()
{
if (state == State.READY)
{
if (rUncompressed)
{
payloadSize = 0;
aRecorder.startRecording();
aRecorder.read(buffer, 0, buffer.length);
}
else
{
mRecorder.start();
}
state = State.RECORDING;
}
else
{
Log.e(RehearsalAudioRecorder.class.getName(), "start() called on illegal state");
state = State.ERROR;
}
}
/**
*
*
* Stops the recording, and sets the state to STOPPED.
* In case of further usage, a reset is needed.
* Also finalizes the wave file in case of uncompressed recording.
*
*/
public void stop()
{
if (state == State.RECORDING)
{
if (rUncompressed)
{
aRecorder.stop();
try
{
fWriter.seek(4); // Write size to RIFF header
fWriter.writeInt(Integer.reverseBytes(36+payloadSize));
fWriter.seek(40); // Write size to Subchunk2Size field
fWriter.writeInt(Integer.reverseBytes(payloadSize));
fWriter.close();
}
catch(IOException e)
{
Log.e(RehearsalAudioRecorder.class.getName(), "I/O exception occured while closing output file");
state = State.ERROR;
}
}
else
{
mRecorder.stop();
}
state = State.STOPPED;
}
else
{
Log.e(RehearsalAudioRecorder.class.getName(), "stop() called on illegal state");
state = State.ERROR;
}
}
/*
*
* Converts a byte[2] to a short, in LITTLE_ENDIAN format
*
*/
private short getShort(byte argB1, byte argB2)
{
return (short)(argB1 | (argB2 << 8));
}
}