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/*
* 11/19/04 1.0 moved to LGPL.
* 29/01/00 Initial version. mdm@techie.com
*-----------------------------------------------------------------------
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*----------------------------------------------------------------------
*/
package javazoom.jl.player;
import javazoom.jl.decoder.Decoder;
import javazoom.jl.decoder.JavaLayerException;
/**
* The <code>AudioDevice</code> interface provides an abstraction for
* a device capable of sounding audio samples. Samples are written to
* the device wia the write() method. The device assumes
* that these samples are signed 16-bit samples taken at the output frequency
* of the decoder. If the decoder outputs more than one channel, the samples for
* each channel are assumed to appear consecutively, with the lower numbered
* channels preceeding higher-numbered channels. E.g. if there are two
* channels, the samples will appear in this order:
* <pre><code>
*
* l0, r0, l1, r1, l2, r2...
*
* where
* l<i>x</i> indicates the <i>x</i>th sample on channel 0
* r<i>x</i> indicates the <i>x</i>th sample on channel 1
* </code></pre>
*
* @since 0.0.8
* @author Mat McGowan
*/
public interface AudioDevice
{
/**
* Prepares the AudioDevice for playback of audio samples.
* @param decoder The decoder that will be providing the audio
* samples.
*
* If the audio device is already open, this method returns silently.
*
*/
public void open(Decoder decoder) throws JavaLayerException;
/**
* Retrieves the open state of this audio device.
*
* @return <code>true</code> if this audio device is open and playing
* audio samples, or <code>false</code> otherwise.
*/
public boolean isOpen();
/**
* Writes a number of samples to this <code>AudioDevice</code>.
*
* @param samples The array of signed 16-bit samples to write
* to the audio device.
* @param offs The offset of the first sample.
* @param len The number of samples to write.
*
* This method may return prior to the samples actually being played
* by the audio device.
*/
public void write(short[] samples, int offs, int len) throws JavaLayerException;
/**
* Closes this audio device. Any currently playing audio is stopped
* as soon as possible. Any previously written audio data that has not been heard
* is discarded.
*
* The implementation should ensure that any threads currently blocking
* on the device (e.g. during a <code>write</code> or <code>flush</code>
* operation should be unblocked by this method.
*/
public void close();
/**
* Blocks until all audio samples previously written to this audio device have
* been heard.
*/
public void flush();
/**
* Retrieves the current playback position in milliseconds.
*/
public int getPosition();
}
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