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#30 - improves silence frame handling. Appends silence to end of MP3 recordings to round them out to whole second intervals and adds an MP3 silence generator to generate 1 second silence frames each interval when there is no audio to broadcast. Previous approach used static silence frame, but we can't generate an exactly 1 second frame, so the remote server was resetting the connection when it detected that we were sending data at over or under rate.

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This commit is contained in:
Denny
2016-12-26 11:52:25 -05:00
parent 524a76e583
commit 5611f594c7
8 changed files with 148 additions and 48 deletions
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39
src/audio/broadcast/AudioBroadcaster.java
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@@ -20,6 +20,7 @@ package audio.broadcast;
import audio.AudioPacket;
import audio.IAudioPacketListener;
import audio.convert.ISilenceGenerator;
import audio.metadata.AudioMetadata;
import controller.ThreadPoolManager;
import org.slf4j.Logger;
@@ -47,7 +48,7 @@ public abstract class AudioBroadcaster implements IAudioPacketListener
private RecordingQueueProcessor mRecordingQueueProcessor = new RecordingQueueProcessor();
private LinkedTransferQueue<StreamableAudioRecording> mAudioRecordingQueue = new LinkedTransferQueue<>();
private byte[] mSilenceFrame;
private ISilenceGenerator mSilenceGenerator;
private Listener<BroadcastEvent> mBroadcastEventListener;
private BroadcastState mBroadcastState = BroadcastState.READY;
@@ -85,8 +86,7 @@ public abstract class AudioBroadcaster implements IAudioPacketListener
mBroadcastConfiguration = broadcastConfiguration;
mDelay = mBroadcastConfiguration.getDelay();
//Create a 1 second silence frame - from 1200 millis of silence
mSilenceFrame = BroadcastFactory.getSilenceFrame(getBroadcastConfiguration().getBroadcastFormat(), 1200);
mSilenceGenerator = BroadcastFactory.getSilenceGenerator(broadcastConfiguration.getBroadcastFormat());
mStreamManager = new StreamManager(threadPoolManager, this,
SystemProperties.getInstance().getApplicationFolder(BroadcastModel.TEMPORARY_STREAM_DIRECTORY));
@@ -326,7 +326,8 @@ public abstract class AudioBroadcaster implements IAudioPacketListener
{
private AtomicBoolean mProcessing = new AtomicBoolean();
private ByteArrayInputStream mInputStream;
private int mChunkSize;
private int mAverageBytesPerInterval;
private long mFinalSilencePadding = 0;
@Override
public void run()
@@ -335,12 +336,18 @@ public abstract class AudioBroadcaster implements IAudioPacketListener
{
if(mInputStream == null || mInputStream.available() <= 0)
{
if(mFinalSilencePadding > 0)
{
broadcastAudio(mSilenceGenerator.generate(mFinalSilencePadding));
mFinalSilencePadding = 0;
}
nextRecording();
}
if(mInputStream != null)
{
int length = Math.min(mChunkSize, mInputStream.available());
int length = Math.min(mAverageBytesPerInterval, mInputStream.available());
byte[] audio = new byte[length];
@@ -357,7 +364,7 @@ public abstract class AudioBroadcaster implements IAudioPacketListener
}
else
{
broadcastAudio(mSilenceFrame);
broadcastAudio(mSilenceGenerator.generate(PROCESSOR_RUN_INTERVAL_MS));
}
mProcessing.set(false);
@@ -395,17 +402,21 @@ public abstract class AudioBroadcaster implements IAudioPacketListener
{
mInputStream = new ByteArrayInputStream(audio);
int wholeIntervalChunks = (int)(recording.getRecordingLength() / PROCESSOR_RUN_INTERVAL_MS);
double intervals = (double)recording.getRecordingLength() / (double)PROCESSOR_RUN_INTERVAL_MS;
//Check for divide by zero situation
if(wholeIntervalChunks == 0)
mAverageBytesPerInterval = (int)((double)mInputStream.available() / intervals);
int wholeIntervals = (int)Math.floor(intervals) + 1;
//Silence padding to transmit at the end to keep stream length at multiples of run interval
mFinalSilencePadding = (wholeIntervals * PROCESSOR_RUN_INTERVAL_MS) -
recording.getRecordingLength();
if(connected())
{
wholeIntervalChunks = 1;
broadcastMetadata(recording.getAudioMetadata());
}
mChunkSize = (int)(mInputStream.available() / wholeIntervalChunks) + 1;
broadcastMetadata(recording.getAudioMetadata());
metadataUpdateRequired = false;
}
}
@@ -423,7 +434,7 @@ public abstract class AudioBroadcaster implements IAudioPacketListener
}
//If we closed out a recording and don't have anything new, send an empty metadata update
if(metadataUpdateRequired)
if(metadataUpdateRequired && connected())
{
broadcastMetadata(null);
}