Hi guys.
We have our transcoder (based on VLC) serving up some H.264 live streams in Asia via RTMP. We are pulling these RTMP streams to our Wowza edge server in Dallas, and using the “liverepeater-edge” stream type.
Everything is smooth, with no buffering or latency. However intermittently (maybe once every 2-3 minutes, and lasts up to 5 seconds) we are seeing what appears to be “scrambled” video. The audio continues to be stable, but for a few seconds the video looks like those seedy Pay-Per-View channels on cable that we curiously tried to watch as kids. 
Example:
http://i.imgur.com/pvzxgn0.jpg
I think it might be happening when action is “faster” like higher framerate. Not sure yet. Viewing the RTMP source directly from Asia we don’t see this issue happening at all.
I hope this is just a tuning related issue, but your help is GREATLY appreciated.
Thanks.
Rezilient
Hi guys.
We have our transcoder (based on VLC) serving up some H.264 live streams in Asia via RTMP. We are pulling these RTMP streams to our Wowza edge server in Dallas, and using the “liverepeater-edge” stream type.
Everything is smooth, with no buffering or latency. However intermittently (maybe once every 2-3 minutes, and lasts up to 5 seconds) we are seeing what appears to be “scrambled” video. The audio continues to be stable, but for a few seconds the video looks like those seedy Pay-Per-View channels on cable that we curiously tried to watch as kids. 
Example:
http://i.imgur.com/pvzxgn0.jpg
I think it might be happening when action is “faster” like higher framerate. Not sure yet. Viewing the RTMP source directly from Asia we don’t see this issue happening at all.
I hope this is just a tuning related issue, but your help is GREATLY appreciated.
Thanks.
Rezilient
Ok it doesn’t seem to be related to framerate or anything occurring on screen, it is just completely random.
We are using the latest version of Wowza 3.5 (trial) on a Linux VM server.
We did some extended testing and confirmed this is not happening from the “source” since the RTMP stream from Asia is not exhibiting this behavior at all. Only the Wowza edge server, both RTMP and HLS versions of the same stream.
Please help, this is preventing us from purchasing a license right now.
Thanks.
Rezilient
Intercontinental re-streaming can be problematic. One thing to try in this case is to move packetization to the edge. On the origin, make the Application.xml /Streams /LiveStreamPacketizers empty, and change the edge Application.xml /Streams /LiveStreamPacketizers to the regular packetizers instead of the repeater packetizers.
This will reduce the traffic between the edge and origin, which might reduce packet loss.
Richard
Then the edge should have the regular packetizers, which they probably do or HLS playback would not work at all.
Are the higher bitrate renditions the problem? The scamble is most likely due to packet loss. I would consider lowering or removing the higher bitrate versions.
However, if your VLC based transcoders is producing an RTMP stream you can push that to a regulation Wowza origin server and re-stream from that from your edge servers. You can use the standard configuration or try packetizing on the edge.
Richard
Ok it doesn’t seem to be related to framerate or anything occurring on screen, it is just completely random.
We are using the latest version of Wowza 3.5 (trial) on a Linux VM server.
We did some extended testing and confirmed this is not happening from the “source” since the RTMP stream from Asia is not exhibiting this behavior at all. Only the Wowza edge server, both RTMP and HLS versions of the same stream.
Please help, this is preventing us from purchasing a license right now.
Thanks.
Rezilient
Anyone? Could it be related to the hardware (VM) that we’re running Wowza on? The cpu doesn’t seem stressed at all. I havent seen this behavior before, but it’s definitely only happening on the Wowza edge server. Help!
Intercontinental re-streaming can be problematic. One thing to try in this case is to move packetization to the edge. On the origin, make the Application.xml /Streams /LiveStreamPacketizers empty, and change the edge Application.xml /Streams /LiveStreamPacketizers to the regular packetizers instead of the repeater packetizers.
This will reduce the traffic between the edge and origin, which might reduce packet loss.
Richard
Thanks Richard. In this case our service provider is not using Wowza at the origin, i believe they are using a hardware trancoder appliance (DVEO). So what is the correct configuration in that case?
Is the “scrambled” effect indicative of a packetization problem?
Thanks.
