Tricaster FMLE 3.2 is causing Audio Video sync issues over time for Live Broadcast.

[pobrejuanito]

Hi,

For last few weeks we have been testing live broadcast using Tricaster and Wowza EC2 instances using RTMP.

Here is our broadcast environment: For Audio/Video, we have microphones hooked up to audio mixer and panasonic video cameras all hooked up to Tricaster 450 series. We are streaming live using RTMP using Tricaster, which I believe is using FMLE. Our stream is originating from Atlanta, GA and sending it to Origin/Balancer Wowza EC2 instance in N. California region. We have 3.0Mbps upload connection. We are streaming @ 512Kbps.

At first, we noticed over time, audio was drifting behind video.

I've searched and tried adding this piece of code to our application XML on the origin and the edges:

<Property>
    <Name>sortPackets</Name>
    <Value>true</Value>
    <Type>Boolean</Type>
</Property>
<Property>
    <Name>sortBufferSize</Name>
    <Value>750</Value>
    <Type>Integer</Type>
</Property>

I also made sure the encoding profile on Tricaster was is baseline profile, level 3.1. We tested with that and audio still drifts behind video.

So my next option was to turn on the dvsyncfeature in config.xml on FMLE 3.2 on Tricaster box. That still caused audio drift issues. I am running out of options here and we are going to start broadcasting soon.

Any wisdom to this novice would be sincerely appreciated.

[randall]

Some suggestions:

What is the audio encoding? Have you tried fiddling with it? What are all the encoder settings.

Check your source stream for problems using a tool such as ffprobe. Does the actual stream match what you've entered in the encoder?

Use the Stream Monitor property AVSyncToolerance with logging enabled to see if the incoming stream timecodes are drifting, and reset it.

Increase the sort buffer, 1000, 2000, etc..

Use a different source encoder, perhaps VLC, ffmpeg, FMLE. If you'd like to hire someone you can request a list of consultants by sending an email to support@wowza.com.

[pobrejuanito]

Hi,

So far here is what I did.

The camera source is set to 720P (30fps)

FMLE Profile I am using is this:

Audio:
Codec: ACC
Bitrate:96Kbps
Sample Frequency: 32000
2 Channel

Video:

24FPS
H.264
Baseline, 3.0
Bitrate: 640Kbps
Resolution: 640x320
Keyframe Frequency: 3

I also copied and pasted the Stream Monitor property on the origin (liveorigin) application.xml. I also increased the sortBuffer to 3000 on liveorigin

So over the 30 minutes of streaming, the audio drifted behind the video about 3 seconds.

Is there any other settings I can adjust? I can accept delay up to 1 second if possible.

Thank you for your help.

[joexromero]

Have you tried streaming at the same framerate as your source - i.e. 30fps instead of 24fps

[pobrejuanito]

Have you tried streaming at the same framerate as your source - i.e. 30fps instead of 24fps

I did, have you experienced similar problem?

[pobrejuanito]

So, after applying all the suggested settings, I've also switched to 24fps at the source and on the FMLE. After an hour of testing, there were no noticeable audio drift issue.

I believe that was the final piece and it works now without apparent drifts.

Anyone have some kind of explanation as to why switching to 24fps helped eliminate audio drift at the encoding side?

Thank you.

[Brandon Rohde]

This was a known problem on the TriCaster when streaming using Flash. We had the same issue. The latest TriCaster update fixes this though. Just log in to your members area of the TriCaster website and download/install the latest version and it will be fixed. If you "Check for Updates" on the TriCaster, it sometimes will say you have the latest version, even if you don't. The members area will tell you what the latest version available is.

-Brandon