We were recently asked to look at how to provide absolute timecodes in a stream, regardless of if the encoder sent them or not. This can be done and is extremely simple to do.
package guru.thewowza.example.absolute;
import com.wowza.wms.application.*;
import com.wowza.wms.amf.*;
import com.wowza.wms.module.*;
import com.wowza.wms.stream.*;
public class Timecode extends ModuleBase
{
public void onAppStart(IApplicationInstance appInstance)
{
String fullname = appInstance.getApplication().getName() + "/" + appInstance.getName();
getLogger().info("onAppStart: " + fullname);
}
public void onAppStop(IApplicationInstance appInstance)
{
String fullname = appInstance.getApplication().getName() + "/" + appInstance.getName();
getLogger().info("onAppStop: " + fullname);
}
public void onStreamCreate(IMediaStream stream)
{
stream.addLivePacketListener(new PacketListener());
}
public void onStreamDestroy(IMediaStream stream)
{
}
class PacketListener implements IMediaStreamLivePacketNotify
{
private boolean firstPacket = false;
private long baseTimeCode = 0L;
private long baseSystemTime = 0L;
private long packetTimeCode = 0L;
public PacketListener()
{
}
public void onLivePacket(IMediaStream stream, AMFPacket thisPacket)
{
if ( this.firstPacket == false )
{
this.firstPacket = true;
this.baseTimeCode = thisPacket.getAbsTimecode();
this.baseSystemTime = System.currentTimeMillis();
}
packetTimeCode = thisPacket.getAbsTimecode()-this.baseTimeCode;
packetTimeCode = packetTimeCode + this.baseSystemTime;
thisPacket.setAbsTimecode(packetTimeCode);
}
}
The code simple determines if this is the first run, sets up a base time from the first packet, gets the current system time and then all packet timecodes are a delta from the first packet with the addition of system time.
You will need to compile this code and then add a module entry in your Application.xml of the following
<Module> <Name>Timecode</Name> <Description>Timecode</Description> <Class>guru.thewowza.example.absolute.Timecode</Class> </Module>
You can see this code in action if you enable the Cupertino chunk based on timecode property
<Property> <Name>cupertinoCalculateChunkIDBasedOnTimecode</Name> <Name>true</Name> <Type>Boolean</Type> </Property>
The packetizer would then show the timecode but it appears to be divided by the chunk duration target, so as below you can see the chunk IDs
LiveStreamPacketizerCupertino.endChunkTS[live/_definst_/myStream]: Add chunk: id:1[146084065] mode:TS[H264,AAC] a/v/k:124/200/4 duration:8620 LiveStreamPacketizerCupertino.endChunkTS[live/_definst_/myStream]: Add chunk: id:2[146084066] mode:TS[H264,AAC] a/v/k:143/250/5 duration:10000 LiveStreamPacketizerCupertino.endChunkTS[live/_definst_/myStream]: Add chunk: id:3[146084067] mode:TS[H264,AAC] a/v/k:144/250/5 duration:9984 LiveStreamPacketizerCupertino.endChunkTS[live/_definst_/myStream]: Add chunk: id:4[146084068] mode:TS[H264,AAC] a/v/k:143/250/5 duration:9984 LiveStreamPacketizerCupertino.endChunkTS[live/_definst_/myStream]: Add chunk: id:5[146084069] mode:TS[H264,AAC] a/v/k:143/250/5 duration:9999 LiveStreamPacketizerCupertino.endChunkTS[live/_definst_/myStream]: Add chunk: id:6[146084070] mode:TS[H264,AAC] a/v/k:144/250/5 duration:9984