Player error

[thechameleon]

Hello, in addition to the Player not playing the music file see here, i am encountering another problem.


i need to read the whole music file as a byte Array, do some decryption, and then pass it into the player. because File IO takes a really long time to complete, im using the following codes:

public void testAudio(){
		try{
			String path = "file:///E:/test.mp3";
			FileConnection fileConnection = (FileConnection) Connector.open(path);
			byte [] fileBytes = new byte[(int) fileConnection.fileSize()];
			InputStream inputStream = new ByteArrayInputStream(fileBytes);
			Player player = Manager.createPlayer(inputStream, "audio/mp3");
			player.realize();
				
			VolumeControl vc = (VolumeControl) player.getControl("VolumeControl");
			vc.setLevel(100);
				
			player.prefetch();
			player.start();
		}catch(Exception e){}
}

when playing on the phone, it gives an Exception javax.microedition.media.MediaException: Prefetch error: -5

wat should i do?

[im2amit]

Is you midlet signed by some trusted certificate? is your code working on emulator ?

thanks,
~Amitabh

[thechameleon]

Is you midlet signed by some trusted certificate? is your code working on emulator ?

thanks,
~Amitabh

yeah, the code's running on the emulator (for the code in the other thread). this one... it's not tested coz of some stuff.

anyway, by trusted cert... did u mean using Symbian Signed? is there a better way to get the cert and the app signed? coz the online signing using Symbian Signed takes quite a while.

[grahamhughes]

    FileConnection fileConnection = (FileConnection) Connector.open(path);
    byte [] fileBytes = new byte[(int) fileConnection.fileSize()];

    // where do you read the data from the file into the array????

    InputStream inputStream = new ByteArrayInputStream(fileBytes);
    Player player = Manager.createPlayer(inputStream, "audio/mp3");

In this code, you are trying to fetch audio data from an array of zeros. Try adding something like:

InputStream fileIn = fileConnection.openInputStream();
int bytesRead = 0;
while (bytesRead < fileBytes.length) {
    bytesRead += fileIn.read(fileBytes, bytesRead, fileBytes.length - bytesRead);
}

Graham.

[Tiger79]

wel for a J2ME app you can't use Symbian Signed... thats for like symbian (c++) apps...
So some known certification companies are Verisign and Thawte...
And well that costs money and it does take time to get a certificate, but thats only once (about 3 to 5 working days), so you wont have to wait all that time every time just to sign an app... You buy the certificate with which you sign your apps from them, but you will be doing the actual signing yourself...

[thechameleon]

In this code, you are trying to fetch audio data from an array of zeros. Try adding something like:

InputStream fileIn = fileConnection.openInputStream();
int bytesRead = 0;
while (bytesRead < fileBytes.length) {
    bytesRead += fileIn.read(fileBytes, bytesRead, fileBytes.length - bytesRead);
}

Graham.

uh.. sorry for that dumb error. i removed a few lines when copying and pasting the codes over some classes...

please assume that the byte Array is filled up with the contents of the file.

the song still does not play... i've tried

InputStream inputStream = fileConnection.openInputStream();
InputStream inputStream = getClass().getResourceAsStream("file:///test.mp3");
InputStream inputStream = new ByteArrayInputStream(fileBytes);

[im2amit]

If your mp3 file is inside the jar file of your app; you can use:

InputStream inputStream = getClass().getResourceAsStream("/test.mp3");

no need to give the file name like: "file:///test.mp3"

i.e. dont use file:// directly give the path.. of test.mp3 inside the JAR.

And remember the size of MP3 file should not be very large as it may overflow your heap memory.

thanks,
~Amitabhn

[thechameleon]

If your mp3 file is inside the jar file of your app; you can use:


no need to give the file name like: "file:///test.mp3"

i.e. dont use file:// directly give the path.. of test.mp3 inside the JAR.

thanks,
~Amitabh

the mp3 file is outside the jar.

[im2amit]

if the file is outside the jar you cannot play it by

InputStream inputStream = getClass().getResourceAsStream("file:///test.mp3");

You need to access the file using JSR-75 FCA, read the bytes and try to play the music bytes using MMAPI.... see the MMAPI demos in SUN WKT.

thanks,
~Amitabh

[thechameleon]

if the file is outside the jar you cannot play it by

You need to access the file using JSR-75 FCA, read the bytes and try to play the music bytes using MMAPI.... see the MMAPI demos in SUN WKT.

thanks,
~Amitabh

public void testAudio(){
		try{
			String path = "file:///E:/test.mp3";
			
			FileConnection fileConnection = (FileConnection) Connector.open(path);
			byte [] fileBytes = new byte[(int) fileConnection.fileSize()];
			InputStream readStream = fileConnection.openInputStream();
			readStream.read(fileBytes);
			
			ByteArrayInputStream inputStream = new ByteArrayInputStream(fileBytes);
			
			Player player = Manager.createPlayer(inputStream, "audio/mp3");
			player.realize();
			
			VolumeControl vc = (VolumeControl) player.getControl("VolumeControl");
			vc.setLevel(100);
			
			player.prefetch();
			long duration = player.getDuration();
			player.start();
			Thread.sleep(duration/1000);

			player.close();
			inputStream.close();
			readStream.close();			
		}catch(Exception e){
			String exceptionString = e.toString();
		}
		
	}

i've tried many different ways, all listed in one of the previous posts; they all either play nothing, or hang my phone. wat am i doing wrong? wat do u recommend i do?

this latest code i posted hangs the phone; i can only exit the application and/or shut down my phone by taking out the battery.

[im2amit]

Which phone you are tring this on ? is your code working on emulator ?

thanks,
~Amiatbh

[grahamhughes]

please assume that the byte Array is filled up with the contents of the file.

I never assume anything.

byte [] fileBytes = new byte[(int) fileConnection.fileSize()];
InputStream readStream = fileConnection.openInputStream();
readStream.read(fileBytes);

This code doesn't guarantee to fille the byte array with the contents of the file. This is a common mistake people make about the method InputStream.read(byte[]). It reads "some number of bytes" from the stream. You need to check the return value to see how many bytes were actually read.

InputStream fileIn = fileConnection.openInputStream();
int bytesRead = 0;
while (bytesRead < fileBytes.length) {
    bytesRead += fileIn.read(fileBytes, bytesRead, fileBytes.length - bytesRead);
}

Also, I suggest you close the file InputStream immediately after you've read the data into the byte array. Don't worry about closing the ByteArrayInputStream, and don't worry (for now) about closing the Player. So, get rid of the code that sleeps. When you've got it playing, used a PlayerListener to detect the end of the sound and close it then.

Graham.

[thechameleon]

I never assume anything.



This code doesn't guarantee to fille the byte array with the contents of the file. This is a common mistake people make about the method InputStream.read(byte[]). It reads "some number of bytes" from the stream. You need to check the return value to see how many bytes were actually read.



Also, I suggest you close the file InputStream immediately after you've read the data into the byte array. Don't worry about closing the ByteArrayInputStream, and don't worry (for now) about closing the Player. So, get rid of the code that sleeps. When you've got it playing, used a PlayerListener to detect the end of the sound and close it then.

Graham.

ah, thanks for the tip about not all the bytes will be read. i didnt know that.

in any case, this is the code:

public void testAudio(){
		try{
			String path = "file:///E:/test.mp3";
			
			FileConnection fileConnection = (FileConnection) Connector.open(path);
			byte [] fileBytes = new byte[(int) fileConnection.fileSize()];
			InputStream readStream = fileConnection.openInputStream();
			String field1String = path;
			
			int bytesRead = readStream.read(fileBytes);
			readStream.close();
			
			
			field1String += "\nRead " + bytesRead +" out of " + fileConnection.fileSize() + " bytes";
			if(bytesRead == fileConnection.fileSize()){
				field1String += "\nAll Read";
			}
			

			field1 = new TextField("test audio", field1String,1024, TextField.ANY);
			ByteArrayInputStream inputStream = new ByteArrayInputStream(fileBytes);
			
			Player player = Manager.createPlayer(inputStream, "audio/mp3");
			player.realize();
			
			VolumeControl vc = (VolumeControl) player.getControl("VolumeControl");
			vc.setLevel(100);
			
			player.prefetch();
			player.start();
			
		}catch(Exception e){
			String exceptionString = e.toString();
			e.printStackTrace();
			field1 = new TextField("Exception", exceptionString,1024, TextField.ANY);
		}
	}

it shows in the TextField:

test audio
file:///E:/test.mp3
Read 4741833 out of 4741833 bytes
All Read

but there's no sound from the player.

[grahamhughes]

OK, but I suggest you change the code to read in a loop anyway. Different devices will behave differently here, depending on the underlying implementation of file access. Also, reading from external files, JAR files, network connections and so on, may behave differently.

No exception? Or do you still get the prefetch error?

Which device (or which emulator)?

Graham.

[thechameleon]

OK, but I suggest you change the code to read in a loop anyway. Different devices will behave differently here, depending on the underlying implementation of file access. Also, reading from external files, JAR files, network connections and so on, may behave differently.

No exception? Or do you still get the prefetch error?

Which device (or which emulator)?

Graham.

well.. im running the code on the N95 8GB. no message, no sounds.