9fee0ec4ca
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7101 a1c6a512-1295-4272-9138-f99709370657
103 lines
3.5 KiB
Java
103 lines
3.5 KiB
Java
/*
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* 11/19/04 1.0 moved to LGPL.
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* 29/01/00 Initial version. mdm@techie.com
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*-----------------------------------------------------------------------
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Library General Public License as published
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* by the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*----------------------------------------------------------------------
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*/
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package javazoom.jl.player;
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import javazoom.jl.decoder.Decoder;
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import javazoom.jl.decoder.JavaLayerException;
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/**
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* The <code>AudioDevice</code> interface provides an abstraction for
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* a device capable of sounding audio samples. Samples are written to
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* the device wia the write() method. The device assumes
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* that these samples are signed 16-bit samples taken at the output frequency
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* of the decoder. If the decoder outputs more than one channel, the samples for
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* each channel are assumed to appear consecutively, with the lower numbered
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* channels preceeding higher-numbered channels. E.g. if there are two
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* channels, the samples will appear in this order:
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* <pre><code>
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*
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* l0, r0, l1, r1, l2, r2...
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*
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* where
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* l<i>x</i> indicates the <i>x</i>th sample on channel 0
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* r<i>x</i> indicates the <i>x</i>th sample on channel 1
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* </code></pre>
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*
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* @since 0.0.8
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* @author Mat McGowan
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*/
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public interface AudioDevice
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{
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/**
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* Prepares the AudioDevice for playback of audio samples.
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* @param decoder The decoder that will be providing the audio
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* samples.
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*
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* If the audio device is already open, this method returns silently.
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*
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*/
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public void open(Decoder decoder) throws JavaLayerException;
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/**
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* Retrieves the open state of this audio device.
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*
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* @return <code>true</code> if this audio device is open and playing
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* audio samples, or <code>false</code> otherwise.
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*/
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public boolean isOpen();
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/**
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* Writes a number of samples to this <code>AudioDevice</code>.
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*
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* @param samples The array of signed 16-bit samples to write
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* to the audio device.
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* @param offs The offset of the first sample.
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* @param len The number of samples to write.
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*
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* This method may return prior to the samples actually being played
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* by the audio device.
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*/
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public void write(short[] samples, int offs, int len) throws JavaLayerException;
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/**
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* Closes this audio device. Any currently playing audio is stopped
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* as soon as possible. Any previously written audio data that has not been heard
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* is discarded.
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*
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* The implementation should ensure that any threads currently blocking
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* on the device (e.g. during a <code>write</code> or <code>flush</code>
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* operation should be unblocked by this method.
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*/
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public void close();
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/**
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* Blocks until all audio samples previously written to this audio device have
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* been heard.
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*/
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public void flush();
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/**
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* Retrieves the current playback position in milliseconds.
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*/
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public int getPosition();
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}
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