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Adds de-emphasis filter to P25 decoded IMBE audio output.

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This commit is contained in:
denny
2015-12-11 13:34:20 -05:00
parent d9fe979ccf
commit 6763a4bdd6
6 changed files with 88 additions and 13 deletions
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21
src/module/decode/p25/audio/P25AudioModule.java
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@@ -6,8 +6,6 @@ import message.IMessageListener;
import message.Message;
import module.Module;
import module.decode.p25.message.ldu.LDUMessage;
import module.decode.p25.message.tdu.TDUMessage;
import module.decode.p25.message.tdu.lc.TDULinkControlMessage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@@ -23,6 +21,8 @@ import audio.squelch.ISquelchStateListener;
import audio.squelch.SquelchState;
import controller.channel.ChannelEvent;
import controller.channel.IChannelEventListener;
import dsp.audio.P25AGC;
import dsp.filter.iir.DeemphasisFilter;
public class P25AudioModule extends Module implements Listener<Message>,
IAudioPacketProvider, IMessageListener, IChannelEventListener,
@@ -43,6 +43,8 @@ public class P25AudioModule extends Module implements Listener<Message>,
private AudioMetadata mAudioMetadata;
private ChannelEventListener mChannelEventListener = new ChannelEventListener();
private SquelchStateListener mSquelchStateListener = new SquelchStateListener();
// private P25AGC mAGC = new P25AGC( 2.0, 10.0 );
private DeemphasisFilter mDeemphasis = new DeemphasisFilter( 48000.0f, 300.0f, 0.6f );
public P25AudioModule( boolean record )
{
@@ -89,9 +91,10 @@ public class P25AudioModule extends Module implements Listener<Message>,
}
/**
* Primary inject point for p25 imbe audio frame messages. Each LDU audio
* message contains 9 imbe voice frames. If the audio is not encrypted,
* we insert each audio frame asynchronously into the audio converter.
* Primary processing method for p25 imbe audio frame messages. Each LDU
* audio message contains 9 imbe voice frames. Each frame is converted to
* audio when the JMBE library is loaded, processed by auto-gain, and
* broadcast to the audio packet listener.
*/
public void receive( Message message )
{
@@ -101,15 +104,15 @@ public class P25AudioModule extends Module implements Listener<Message>,
{
LDUMessage ldu = (LDUMessage)message;
/* If we detect a valid LDU message with the encryption flag
* set to true, we toggle the encrypted audio state until we
* receive the first TDU or TDULC message, then reset it. */
/* Only process unencrypted audio frames */
if( !( ldu.isValid() && ldu.isEncrypted() ) )
{
for( byte[] frame: ((LDUMessage)message).getIMBEFrames() )
for( byte[] frame: ldu.getIMBEFrames() )
{
float[] audio = mAudioConverter.decode( frame );
audio = mDeemphasis.filter( audio );
mAudioPacketListener.receive(
new AudioPacket( audio, mAudioMetadata.copyOf() ) );
}