3 files changed, 83 insertions, 39 deletions
diff --git a/src/java/com/jogamp/common/av/AudioSink.java b/src/java/com/jogamp/common/av/AudioSink.java
index 9c31244..ac6441a 100644
--- a/src/java/com/jogamp/common/av/AudioSink.java
+++ b/src/java/com/jogamp/common/av/AudioSink.java
@@ -197,21 +197,6 @@ public interface AudioSink {
     public boolean setVolume(float v);
 
     /**
-     * Returns the preferred sample-rate of this sink, i.e. mixer frequency in Hz, e.g. 41000 or 48000.
-     * <p>
-     * The preferred sample-rate is guaranteed to be supported
-     * and shall reflect this sinks most native format,
-     * i.e. best performance w/o data conversion.
-     * </p>
-     * <p>
-     * May return {@link AudioSink#DefaultFormat}'s  44100 default if undefined.
-     * </p>
-     * @see #init(AudioFormat, float, int, int, int)
-     * @see #isSupported(AudioFormat)
-     */
-    public int getPreferredSampleRate();
-
-    /**
      * Returns the number of sources the used device is capable to mix.
      * <p>
      * This device attribute is only formally exposed and not used,
@@ -236,32 +221,64 @@ public interface AudioSink {
     public float getDefaultLatency();
 
     /**
-     * Returns the preferred {@link AudioFormat} by this sink.
+     * Returns the native {@link AudioFormat} by this sink.
      * <p>
-     * The preferred format is guaranteed to be supported
+     * The native format is guaranteed to be supported
      * and shall reflect this sinks most native format,
      * i.e. best performance w/o data conversion.
      * </p>
      * <p>
+     * The native format is not impacted by {@link #setChannelLimit(int)}.
+     * </p>
+     * <p>
+     * May return {@link AudioSink#DefaultFormat} if undefined.
+     * </p>
+     * @see #init(AudioFormat, float, int, int, int)
+     */
+    public AudioFormat getNativeFormat();
+
+    /**
+     * Returns the preferred {@link AudioFormat} by this sink.
+     * <p>
+     * The preferred format is a subset of {@link #getNativeFormat()},
+     * impacted by {@link #setChannelLimit(int)}.
+     * </p>
+     * <p>
      * Known {@link #AudioFormat} attributes considered by implementations:
      * <ul>
      *   <li>ALAudioSink: {@link AudioFormat#sampleRate}.
+     *   <li>ALAudioSink: {@link AudioFormat#channelCount}
      * </ul>
      * </p>
-     * <p>
-     * May return {@link AudioSink#DefaultFormat} if undefined.
-     * </p>
+     * @see #getNativeFormat()
      * @see #init(AudioFormat, float, int, int, int)
+     * @see #setChannelLimit(int)
      * @see #isSupported(AudioFormat)
-     * @see #getPreferredSampleRate()
      */
     public AudioFormat getPreferredFormat();
 
-    /** Return the maximum number of supported channels, e.g. 1 for mono, 2 for stereo, etc. */
-    public int getMaxSupportedChannels();
+    /**
+     * Limit maximum supported audio channels by user.
+     * <p>
+     * Must be set before {@link #getPreferredFormat()}, {@link #isSupported(AudioFormat)} and naturally {@link #init(AudioFormat, int, int, int, int)}.
+     * </p>
+     * <p>
+     * May be utilized to enforce 1 channel (mono) downsampling
+     * in combination with JOAL/OpenAL to experience spatial 3D position effects.
+     * </p>
+     * @param cc maximum supported audio channels, will be clipped [1..{@link #getNativeFormat()}.{@link AudioFormat#channelCount channelCount}]
+     * @see #getNativeFormat()
+     * @see #getPreferredFormat()
+     * @see #isSupported(AudioFormat)
+     * @see #init(AudioFormat, int, int, int, int)
+     */
+    public void setChannelLimit(final int cc);
 
     /**
      * Returns true if the given format is supported by the sink, otherwise false.
+     * <p>
+     * The {@link #getPreferredFormat()} is used to validate compatibility with the given format.
+     * </p>
      * @see #init(AudioFormat, float, int, int, int)
      * @see #getPreferredFormat()
      */
@@ -275,7 +292,7 @@ public interface AudioSink {
      * <p>
      * Caller shall validate <code>requestedFormat</code> via {@link #isSupported(AudioFormat)}
      * beforehand and try to find a suitable supported one.
-     * {@link #getPreferredFormat()} and {@link #getMaxSupportedChannels()} may help.
+     * {@link #getPreferredFormat()} may help.
      * </p>
      * @param requestedFormat the requested {@link AudioFormat}.
      * @param frameDurationHint average {@link AudioFrame} duration hint in milliseconds.
diff --git a/src/java/jogamp/common/av/JavaSoundAudioSink.java b/src/java/jogamp/common/av/JavaSoundAudioSink.java
index d3ddda9..58f0fec 100644
--- a/src/java/jogamp/common/av/JavaSoundAudioSink.java
+++ b/src/java/jogamp/common/av/JavaSoundAudioSink.java
@@ -61,6 +61,9 @@ public final class JavaSoundAudioSink implements AudioSink {
     private int bufferCount;
     private final byte [] sampleData = new byte[BUFFER_SIZE];
     private boolean available = false;
+    private final AudioFormat nativeFormat;
+    private int userMaxChannels = 8;
+    private AudioFormat preferredFormat = null;
     private AudioFormat chosenFormat = null;
 
     private volatile boolean playRequested = false;
@@ -79,8 +82,12 @@ public final class JavaSoundAudioSink implements AudioSink {
     public JavaSoundAudioSink() {
         available = false;
         if( !staticAvailable ) {
+            nativeFormat = DefaultFormat;
             return;
         }
+        nativeFormat = new AudioFormat(DefaultFormat.sampleRate, DefaultFormat.sampleSize, getMaxSupportedChannels(),
+                                       DefaultFormat.signed, DefaultFormat.fixedP, DefaultFormat.planar, DefaultFormat.littleEndian);
+        preferredFormat = nativeFormat;
         available = true;
     }
 
@@ -118,11 +125,6 @@ public final class JavaSoundAudioSink implements AudioSink {
     }
 
     @Override
-    public int getPreferredSampleRate() {
-        return DefaultFormat.sampleRate;
-    }
-
-    @Override
     public int getSourceCount() {
         return -1;
     }
@@ -138,17 +140,41 @@ public final class JavaSoundAudioSink implements AudioSink {
     }
 
     @Override
+    public final AudioFormat getNativeFormat() {
+        return nativeFormat;
+    }
+
+    @Override
     public AudioFormat getPreferredFormat() {
         return DefaultFormat;
     }
 
     @Override
-    public final int getMaxSupportedChannels() {
-        return 2;
+    public final void setChannelLimit(final int cc) {
+        userMaxChannels = Math.min(8, Math.max(1, cc));
+        preferredFormat = new AudioFormat(nativeFormat.sampleRate,
+                                       nativeFormat.sampleSize, getMaxSupportedChannels(),
+                                       nativeFormat.signed, nativeFormat.fixedP,
+                                       nativeFormat.planar, nativeFormat.littleEndian);
+        if( DEBUG ) {
+            System.out.println("ALAudioSink: channelLimit "+userMaxChannels+", preferredFormat "+preferredFormat);
+        }
+    }
+
+    private final int getMaxSupportedChannels() {
+        final int cc = 2;
+        return Math.min(userMaxChannels, cc);
     }
 
     @Override
     public final boolean isSupported(final AudioFormat format) {
+        if( format.planar != preferredFormat.planar ||
+            format.fixedP != preferredFormat.fixedP ||
+            format.sampleRate > preferredFormat.sampleRate ||
+            format.channelCount > preferredFormat.channelCount )
+        {
+            return false;
+        }
         return true;
     }
 
@@ -157,6 +183,9 @@ public final class JavaSoundAudioSink implements AudioSink {
         if( !staticAvailable ) {
             return false;
         }
+        if( !isSupported(requestedFormat) ) {
+            return false;
+        }
         // Create the audio format we wish to use
         format = new javax.sound.sampled.AudioFormat(requestedFormat.sampleRate, requestedFormat.sampleSize, requestedFormat.channelCount, requestedFormat.signed, !requestedFormat.littleEndian);
 
diff --git a/src/java/jogamp/common/av/NullAudioSink.java b/src/java/jogamp/common/av/NullAudioSink.java
index 19b0acb..904b863 100644
--- a/src/java/jogamp/common/av/NullAudioSink.java
+++ b/src/java/jogamp/common/av/NullAudioSink.java
@@ -84,11 +84,6 @@ public final class NullAudioSink implements AudioSink {
     }
 
     @Override
-    public int getPreferredSampleRate() {
-        return DefaultFormat.sampleRate;
-    }
-
-    @Override
     public int getSourceCount() {
         return -1;
     }
@@ -104,16 +99,19 @@ public final class NullAudioSink implements AudioSink {
     }
 
     @Override
-    public AudioFormat getPreferredFormat() {
+    public AudioFormat getNativeFormat() {
         return DefaultFormat;
     }
 
     @Override
-    public final int getMaxSupportedChannels() {
-        return 8;
+    public AudioFormat getPreferredFormat() {
+        return DefaultFormat;
     }
 
     @Override
+    public void setChannelLimit(final int cc) { }
+
+    @Override
     public final boolean isSupported(final AudioFormat format) {
         /**
          * If we like to emulate constraints ..