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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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34
src/audio/broadcast/BroadcastFactory.java
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@@ -33,7 +33,9 @@ import audio.broadcast.shoutcast.v1.ShoutcastV1Configuration;
import audio.broadcast.shoutcast.v2.ShoutcastV2AudioBroadcaster;
import audio.broadcast.shoutcast.v2.ShoutcastV2Configuration;
import audio.convert.IAudioConverter;
import audio.convert.ISilenceGenerator;
import audio.convert.MP3AudioConverter;
import audio.convert.MP3SilenceGenerator;
import controller.ThreadPoolManager;
import gui.editor.Editor;
import gui.editor.EmptyEditor;
@@ -53,6 +55,20 @@ public class BroadcastFactory
public static final int MP3_MONO_16_KHZ_BITRATE = 16;
public static final boolean MP3_CONSTANT_BITRATE = false;
private static MP3AudioConverter MP3_SILENT_FRAME_GENERATOR;
static
{
MP3_SILENT_FRAME_GENERATOR = new MP3AudioConverter(MP3Recorder.MP3_BIT_RATE, MP3Recorder.CONSTANT_BIT_RATE);
//We have to charge the converter pipeline with 1200 milliseconds to get 1 second of audio the first time
float[] silence = new float[9600]; //1200 milliseconds at 8000 kHz
AudioPacket silencePacket = new AudioPacket(silence, null);
List<AudioPacket> silencePackets = new ArrayList<>();
silencePackets.add(silencePacket);
MP3_SILENT_FRAME_GENERATOR.convert(silencePackets);
}
/**
* Creates an audio streaming broadcaster for the configuration
@@ -194,23 +210,15 @@ public class BroadcastFactory
}
}
public static byte[] getSilenceFrame(BroadcastFormat format, long duration)
public static ISilenceGenerator getSilenceGenerator(BroadcastFormat format)
{
int length = (int)(duration * 8); //8000 Hz sample rate
float[] silence = new float[length];
AudioPacket silencePacket = new AudioPacket(silence, null);
List<AudioPacket> silencePackets = new ArrayList<>();
silencePackets.add(silencePacket);
switch(format)
switch (format)
{
case MP3:
MP3AudioConverter converter = new MP3AudioConverter(MP3Recorder.MP3_BIT_RATE,
MP3Recorder.CONSTANT_BIT_RATE);
return converter.convert(silencePackets);
return new MP3SilenceGenerator();
default:
throw new IllegalArgumentException("Unrecognized broadcast format: " + format.name());
throw new IllegalArgumentException("Unrecognized broadcast format [" + format +
"] can't create silence generator");
}
}
}