From a363312ec6082aac666bc067184e0a876d6301f3 Mon Sep 17 00:00:00 2001
From: paweldomas <pawel.domas@jitsi.org>
Date: Thu, 12 Jun 2014 14:41:05 +0200
Subject: [PATCH] Adds SilenceAudioSystem which can be used in server type
technologies.
---
.../neomedia/device/AudioSilenceSystem.java | 50 +++
.../impl/neomedia/device/AudioSystem.java | 2 +
.../impl/neomedia/device/DeviceSystem.java | 1 +
.../protocol/audiosilence/DataSource.java | 366 ++++++++++++++++++
4 files changed, 419 insertions(+)
create mode 100644 src/org/jitsi/impl/neomedia/device/AudioSilenceSystem.java
create mode 100644 src/org/jitsi/impl/neomedia/jmfext/media/protocol/audiosilence/DataSource.java
diff --git a/src/org/jitsi/impl/neomedia/device/AudioSilenceSystem.java b/src/org/jitsi/impl/neomedia/device/AudioSilenceSystem.java
new file mode 100644
index 00000000..c7a699e1
--- /dev/null
+++ b/src/org/jitsi/impl/neomedia/device/AudioSilenceSystem.java
@@ -0,0 +1,50 @@
+/*
+ * Jitsi, the OpenSource Java VoIP and Instant Messaging client.
+ *
+ * Distributable under LGPL license.
+ * See terms of license at gnu.org.
+ */
+package org.jitsi.impl.neomedia.device;
+
+import org.jitsi.impl.neomedia.jmfext.media.protocol.audiosilence.*;
+
+import javax.media.*;
+import java.util.*;
+
+/**
+ * Audio system used by server side technologies that do not capture any sound.
+ * The device is producing silence.
+ *
+ * @author Pawel Domas
+ */
+public class AudioSilenceSystem
+ extends AudioSystem
+{
+ private static final String LOCATOR_PROTOCOL
+ = LOCATOR_PROTOCOL_AUDIOSILENCE;
+
+ protected AudioSilenceSystem()
+ throws Exception
+ {
+ super(AudioSystem.LOCATOR_PROTOCOL_AUDIOSILENCE);
+ }
+
+ @Override
+ protected void doInitialize()
+ throws Exception
+ {
+ CaptureDeviceInfo2 captureDevice
+ = new CaptureDeviceInfo2(
+ "AudioSilenceCaptureDevice",
+ new MediaLocator(LOCATOR_PROTOCOL + ":"),
+ DataSource.SUPPORTED_FORMATS,
+ null, null, null);
+
+ List<CaptureDeviceInfo2> captureDevices
+ = new ArrayList<CaptureDeviceInfo2>(1);
+
+ captureDevices.add(captureDevice);
+
+ setCaptureDevices(captureDevices);
+ }
+}
diff --git a/src/org/jitsi/impl/neomedia/device/AudioSystem.java b/src/org/jitsi/impl/neomedia/device/AudioSystem.java
index 5f7343c4..327356c2 100644
--- a/src/org/jitsi/impl/neomedia/device/AudioSystem.java
+++ b/src/org/jitsi/impl/neomedia/device/AudioSystem.java
@@ -87,6 +87,8 @@ public enum DataFlow
public static final String LOCATOR_PROTOCOL_AUDIORECORD = "audiorecord";
+ public static final String LOCATOR_PROTOCOL_AUDIOSILENCE = "audiosilence";
+
public static final String LOCATOR_PROTOCOL_JAVASOUND = "javasound";
/**
diff --git a/src/org/jitsi/impl/neomedia/device/DeviceSystem.java b/src/org/jitsi/impl/neomedia/device/DeviceSystem.java
index d940fe58..ddd72f28 100644
--- a/src/org/jitsi/impl/neomedia/device/DeviceSystem.java
+++ b/src/org/jitsi/impl/neomedia/device/DeviceSystem.java
@@ -196,6 +196,7 @@ public static void initializeDeviceSystems(MediaType mediaType)
OSUtils.IS_WINDOWS ? ".WASAPISystem" : null,
OSUtils.IS_MAC ? ".MacCoreaudioSystem" : null,
OSUtils.IS_ANDROID ? null : ".PortAudioSystem",
+ ".AudioSilenceSystem",
".NoneAudioSystem"
};
break;
diff --git a/src/org/jitsi/impl/neomedia/jmfext/media/protocol/audiosilence/DataSource.java b/src/org/jitsi/impl/neomedia/jmfext/media/protocol/audiosilence/DataSource.java
new file mode 100644
index 00000000..0e7fbac1
--- /dev/null
+++ b/src/org/jitsi/impl/neomedia/jmfext/media/protocol/audiosilence/DataSource.java
@@ -0,0 +1,366 @@
+/*
+ * Jitsi, the OpenSource Java VoIP and Instant Messaging client.
+ *
+ * Distributable under LGPL license.
+ * See terms of license at gnu.org.
+ */
+package org.jitsi.impl.neomedia.jmfext.media.protocol.audiosilence;
+
+import org.jitsi.impl.neomedia.codec.*;
+import org.jitsi.impl.neomedia.jmfext.media.protocol.*;
+import org.jitsi.impl.neomedia.jmfext.media.renderer.audio.*;
+import org.jitsi.util.*;
+
+import javax.media.*;
+import javax.media.control.*;
+import javax.media.format.*;
+import javax.media.protocol.*;
+import java.io.*;
+import java.util.*;
+
+/**
+ * Implements a <tt>CaptureDevice</tt> which provides silence in the form of
+ * audio media.
+ *
+ * @author Lyubomir Marinov
+ * @author Pawel Domas
+ */
+public class DataSource
+ extends AbstractPushBufferCaptureDevice
+{
+ /**
+ * The logger.
+ */
+ private final static Logger logger = Logger.getLogger(DataSource.class);
+
+ /**
+ * The compile-time flag which determines whether
+ * <tt>AudioSilenceCaptureDevice</tt> and, more specifically,
+ * <tt>AudioSilenceStream</tt> are to be used by <tt>AudioMixer</tt> for the
+ * mere purposes of ticking the clock which makes <tt>AudioMixer</tt> read
+ * media from its inputs, mix it, and write it to its outputs. The preferred
+ * value is <tt>true</tt> because it causes the <tt>AudioMixer</tt> to not
+ * push media unless at least one <tt>Channel</tt> is receiving actual
+ * media.
+ */
+ private static final boolean CLOCK_ONLY = true;
+
+ /**
+ * The interval of time in milliseconds between two consecutive ticks of the
+ * clock used by <tt>AudioSilenceCaptureDevice</tt> and, more specifically,
+ * <tt>AudioSilenceStream</tt>.
+ */
+ private static final long CLOCK_TICK_INTERVAL = 20;
+
+ /**
+ * The list of <tt>Format</tt>s supported by the
+ * <tt>AudioSilenceCaptureDevice</tt> instances.
+ */
+ public static final Format[] SUPPORTED_FORMATS
+ = new Format[]
+ {
+ new AudioFormat(
+ AudioFormat.LINEAR,
+ 48000,
+ 16,
+ 1,
+ AudioFormat.LITTLE_ENDIAN,
+ AudioFormat.SIGNED,
+ Format.NOT_SPECIFIED,
+ Format.NOT_SPECIFIED,
+ Format.byteArray)
+ };
+
+ /**
+ * {@inheritDoc}
+ *
+ * Implements
+ * {@link AbstractPushBufferCaptureDevice#createStream(int, FormatControl)}.
+ */
+ @Override
+ protected AudioSilenceStream createStream(
+ int streamIndex,
+ FormatControl formatControl)
+ {
+ return new AudioSilenceStream(this, formatControl);
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * Overrides the super implementation in order to return the list of
+ * <tt>Format</tt>s hardcoded as supported in
+ * <tt>AudioSilenceCaptureDevice</tt> because the super looks them up by
+ * <tt>CaptureDeviceInfo</tt> and this instance does not have one.
+ */
+ @Override
+ protected Format[] getSupportedFormats(int streamIndex)
+ {
+ return SUPPORTED_FORMATS.clone();
+ }
+
+ /**
+ * Implements a <tt>PushBufferStream</tt> which provides silence in the form
+ * of audio media.
+ */
+ private static class AudioSilenceStream
+ extends AbstractPushBufferStream<DataSource>
+ implements Runnable
+ {
+ /**
+ * The indicator which determines whether {@link #start()} has been
+ * invoked on this instance without an intervening {@link #stop()}.
+ */
+ private boolean started;
+
+ /**
+ * The <tt>Thread</tt> which pushes available media data out of this
+ * instance to its consumer i.e. <tt>BufferTransferHandler</tt>.
+ */
+ private Thread thread;
+
+ /**
+ * Initializes a new <tt>AudioSilenceStream</tt> which is to be exposed
+ * by a specific <tt>AudioSilenceCaptureDevice</tt> and which is to have
+ * its <tt>Format</tt>-related information abstracted by a specific
+ * <tt>FormatControl</tt>.
+ *
+ * @param dataSource the <tt>AudioSilenceCaptureDevice</tt> which is
+ * initializing the new instance and which is to expose it in its array
+ * of <tt>PushBufferStream</tt>s
+ * @param formatControl the <tt>FormatControl</tt> which is to abstract
+ * the <tt>Format</tt>-related information of the new instance
+ */
+ public AudioSilenceStream(
+ DataSource dataSource,
+ FormatControl formatControl)
+ {
+ super(dataSource, formatControl);
+ }
+
+ /**
+ * Reads available media data from this instance into a specific
+ * <tt>Buffer</tt>.
+ *
+ * @param buffer the <tt>Buffer</tt> to write the available media data
+ * into
+ * @throws IOException if an I/O error has prevented the reading of
+ * available media data from this instance into the specified
+ * <tt>buffer</tt>
+ */
+ @Override
+ public void read(Buffer buffer)
+ throws IOException
+ {
+ if (CLOCK_ONLY)
+ {
+ buffer.setLength(0);
+ }
+ else
+ {
+ AudioFormat format = (AudioFormat) getFormat();
+ int frameSizeInBytes
+ = format.getChannels()
+ * (((int) format.getSampleRate()) / 50)
+ * (format.getSampleSizeInBits() / 8);
+
+ byte[] data
+ = AbstractCodec2.validateByteArraySize(
+ buffer,
+ frameSizeInBytes,
+ false);
+
+ Arrays.fill(data, 0, frameSizeInBytes, (byte) 0);
+
+ buffer.setFormat(format);
+ buffer.setLength(frameSizeInBytes);
+ buffer.setOffset(0);
+ }
+ }
+
+ /**
+ * Runs in {@link #thread} and pushes available media data out of this
+ * instance to its consumer i.e. <tt>BufferTransferHandler</tt>.
+ */
+ @Override
+ public void run()
+ {
+ try
+ {
+ /*
+ * Make sure that the current thread which implements the actual
+ * ticking of the clock implemented by this instance uses a
+ * thread priority considered appropriate for audio processing.
+ */
+ AbstractAudioRenderer.useAudioThreadPriority();
+
+ /*
+ * The method implements a clock which ticks at a certain and
+ * regular interval of time which is not affected by the
+ * duration of the execution of, for example, the invocation of
+ * BufferTransferHandler.transferData(PushBufferStream).
+ *
+ * XXX The implementation utilizes System.currentTimeMillis()
+ * and, consequently, may be broken by run-time adjustments to
+ * the system time.
+ */
+ long tickTime = System.currentTimeMillis();
+
+ while (true)
+ {
+ long sleepInterval = tickTime - System.currentTimeMillis();
+ boolean tick = (sleepInterval <= 0);
+
+ if (tick)
+ {
+ /*
+ * The current thread has woken up just in time or too
+ * late for the next scheduled clock tick and,
+ * consequently, the clock should tick right now.
+ */
+ tickTime += CLOCK_TICK_INTERVAL;
+ }
+ else
+ {
+ /*
+ * The current thread has woken up too early for the
+ * next scheduled clock tick and, consequently, it
+ * should sleep until the time of the next scheduled
+ * clock tick comes.
+ */
+ try
+ {
+ Thread.sleep(sleepInterval);
+ }
+ catch (InterruptedException ie)
+ {
+ Thread.currentThread().interrupt();
+ }
+ /*
+ * The clock will not tick and spurious wakeups will be
+ * handled. However, the current thread will first check
+ * whether it is still utilized by this
+ * AudioSilenceStream in order to not delay stop
+ * requests.
+ */
+ }
+
+ synchronized (this)
+ {
+ /*
+ * If the current Thread is no longer utilized by this
+ * AudioSilenceStream, it no longer has the right to
+ * touch it. If this AudioSilenceStream has been
+ * stopped, the current Thread should stop as well.
+ */
+ if ((thread != Thread.currentThread()) || !started)
+ break;
+ }
+
+ if (tick)
+ {
+ BufferTransferHandler transferHandler
+ = this.transferHandler;
+
+ if (transferHandler != null)
+ {
+ try
+ {
+ transferHandler.transferData(this);
+ }
+ catch (Throwable t)
+ {
+ if (t instanceof ThreadDeath)
+ throw (ThreadDeath) t;
+ else
+ {
+ logger.error(t, t);
+ }
+ }
+ }
+ }
+ }
+ }
+ finally
+ {
+ synchronized (this)
+ {
+ if (thread == Thread.currentThread())
+ {
+ thread = null;
+ started = false;
+ notifyAll();
+ }
+ }
+ }
+ }
+
+ /**
+ * Starts the transfer of media data from this instance.
+ *
+ * @throws IOException if an error has prevented the start of the
+ * transfer of media from this instance
+ */
+ @Override
+ public synchronized void start()
+ throws IOException
+ {
+ if (thread == null)
+ {
+ String className = getClass().getName();
+
+ thread = new Thread(this, className);
+ thread.setDaemon(true);
+
+ boolean started = false;
+
+ try
+ {
+ thread.start();
+ started = true;
+ }
+ finally
+ {
+ this.started = started;
+ if (!started)
+ {
+ thread = null;
+ notifyAll();
+
+ throw new IOException("Failed to start " + className);
+ }
+ }
+ }
+ }
+
+ /**
+ * Stops the transfer of media data from this instance.
+ *
+ * @throws IOException if an error has prevented the stopping of the
+ * transfer of media from this instance
+ */
+ @Override
+ public synchronized void stop()
+ throws IOException
+ {
+ this.started = false;
+ notifyAll();
+
+ boolean interrupted = false;
+
+ while (thread != null)
+ {
+ try
+ {
+ wait();
+ }
+ catch (InterruptedException ie)
+ {
+ interrupted = true;
+ }
+ }
+ if (interrupted)
+ Thread.currentThread().interrupt();
+ }
+ }
+}
--
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