Audio behind Video when Streaming from Hudl Camera

[jaredsACHS]

Good Morning,
I work for a public school and we use a Hudl camera to live stream our games. The camera is connected through the network and has an audio and video device that come through one IP. If I am not streaming, it seems like the audio and video are pretty much in sync with each and stay that way. The issue is that when I start the stream, it seems like audio is instantly about 10 seconds behind the and only get worse from there as it seem to get further and further off to the point that I can not tell what whistle is for what play with 100% certainty. I have reached out to Hudl and they said that they could not provide any insight since we are using OBS. They have their own software called Production Truck but I only have a windows machine to run it on and they no longer support that either since they only mention Mac in their documentation now. Can anyone give me some insight into somethings to look at or tests to run to try and figure out what the issue is and hopefully how to resolve it? Any ideas are welcome as I have very little experience in streaming with OBS and all of the research that I have done is for video being behind the audio not audio behind the video.

 

[AaronD]

If I am not streaming, it seems like the audio and video are pretty much in sync with each and stay that way. The issue is that when I start the stream, it seems like audio is instantly about 10 seconds behind the and only get worse from there...

Normally, I'd say to either:

• Tweak the Sync Delay in the Advanced Audio Properties by trial and error until the stream is right.
  or
• Do something different with OBS's Monitor so that it doesn't increase ad infinitum. Because that's a known problem with the Monitor.

But you say that the problem only exists when you stream and not when you don't? That's a new one for me.

Does the audio snap back into alignment when you stop streaming? Or does it stay wrong, or keep getting further out of sync?
How, and where in the chain, are you measuring the sync?

How are you actually streaming?

• Direct from OBS?
• Fullscreen projector and Audio Monitor to a standalone hardware encoder?
  • There's that Monitor problem, but it *should* be consistent regardless of streaming or not.
• Something else?

 

[jaredsACHS]

Normally, I'd say to either:

• Tweak the Sync Delay in the Advanced Audio Properties by trial and error until the stream is right.
  or
• Do something different with OBS's Monitor so that it doesn't increase ad infinitum. Because that's a known problem with the Monitor.

But you say that the problem only exists when you stream and not when you don't? That's a new one for me.

Does the audio snap back into alignment when you stop streaming? Or does it stay wrong, or keep getting further out of sync?
How, and where in the chain, are you measuring the sync?

How are you actually streaming?

• Direct from OBS?
• Fullscreen projector and Audio Monitor to a standalone hardware encoder?
  • There's that Monitor problem, but it *should* be consistent regardless of streaming or not.
• Something else?

Thank you for the reply AaronD! I don't see it in OBS itself but rather in the stream. I have attempted to use the Sync Delay but it has been a moving target it seems. I have not used the monitor during my live streams so I don't believe my issue lies there.

I am not sure how to answer the "How are you actually streaming?" question but I will try and explain the best I can. With Hudl, we get access to a portal (formerly BlueFrame Technologies if that helps) and I get a streaming URL/Host and a Stream Name/Key. I take those to the Stream tab on OBS Setting and paste them in the Destination area in the corresponding fields. I also use "Custom" as the service on the same screen.

I will say that I just did a test stream to the platform where I was standing in the gym and bounced a ball and adjusted the Sync Delay to -750 and that seemed to be pretty spot on with the video. The hard part is that during the day, when my network is taxed more with all of the school's devices connecting to the internet, I have no issues. Then game time comes around and then the issues show up.

Now that I am typing all of this out it is sounding like an issue on their end. I welcome your thought on this topic and if you need any further clarification on anything, please let me know and I will get you the answers.

 

[AaronD]

With Hudl, we get access to a portal (formerly BlueFrame Technologies if that helps) and I get a streaming URL/Host and a Stream Name/Key. I take those to the Stream tab on OBS Setting and paste them in the Destination area in the corresponding fields. I also use "Custom" as the service on the same screen.

That would be streaming directly from OBS.

Occasionally, someone will use a physical box that takes a video signal - usually HDMI - and streams that. They're often associated with a specific streaming service, but there are standalone ones as well. To use OBS with one of those, the computer needs to have a multi-screen configuration, with that box as one of the "screens", put a full-screen projector on that screen in OBS, and send OBS's Monitor to the corresponding audio device. Then the Monitor becomes the stream audio, and you need to keep that in mind as you set things up.
But you're not doing that.

...Sync Delay to -750 and that seemed to be pretty spot on with the video.

I'm kinda surprised that worked! 750ms is 3/4 second, and negative numbers eat into the buffer that is normally used to handle hiccups. I guess if it works it works, but I'd consider it kinda risky.

Better to delay the picture (there are filters for that), and keep the Sync Delay positive or zero.

The hard part is that during the day, when my network is taxed more with all of the school's devices connecting to the internet, I have no issues. Then game time comes around and then the issues show up.

I think that's actually the easy part. Everyone packed together, on the same network, and trying to stream the game themselves, text, send pictures, etc. could easily be what causes it to choke.

It also hints at a possible solution. If your media-critical network is the same as what everyone else connects to and swamps, then that could easily be the problem. Can you get the media-critical stuff onto its own dedicated network that has *nothing else* on it?

Ideally, that'd be dedicated wiring and dedicated physical boxes, that are all yours, and the IT guys stay off of it except to give you a tunnel to the internet, with guaranteed bandwidth at everyone else's expense. And it would all be wired, because wireless is a mess during a game.