Audio Syncing

[VSW]

So we are having difficulty keeping our audio synced to the video during livestreaming at our Church.

We stream at 1080p @ 29.97 fps. We have the latest NDI tools installed. We use 2 Birddog 4k cameras (the P400s) wired directly via CAT6 to a new Ubiquiti GB switch and then to our computer all over a GB network. The cameras are set at 1080p @ 29.97 fps. We use x264 compression. The audio comes in directly via an analogue to digital mixer then to a USB port on our computer. Our audio is set to mono at 44.1 kHz with a 160 bitrate. We have added about a 400ms delay in OBS to the audio. However, at times the audio drifts in and out of sync with the video, generally the video falls behind. I assume that the audio remains constant and it is the video input that is variable. Can't seem to keep the video and audio matched.

Just wondering if there is any particular setting needed to keep the audio synced to the video. Why does the time between the audio and video vary? Would it be better to have the audio converted to an ndi source? I am thinking of installing the Audinate Dante Avio to see if that would assist?

We use 64 bit Windows 10 laptop with an i7 9th generation intel chip and a Nvidia GeForce 1650 graphics chip. We have 16 GB of ram. We only run OBS when streaming.

Any feedback is most welcome.

Thanks.

 

[Lawrence_SoCal]

Check your OBS log... do you have audio devices at both 44.1KHz and 48? usual recommendation is to change all to 48, but depends on you audio feed

Are you doing hardware resource monitoring to make sure PC isn't overloaded?

Have you made sure the various NDI related drivers all up-to-date?
Do you have someone who truly knows how to make sure Win10 is effectively setup (good hygiene, unnecessary eye candy & background processes, etc disabled/turned off)?
Is your PC firewall off from any other devices that might interrupt/try to communicate with it?

 

[VSW]

Thank you for your reply.

Our audio is set to 44.1 kHz in OBS, Windows and the M-Audio interface device. I earlier attempted to use 48 kHz, but it would not work, so switched all settings to 44.1.

Our laptop is only used for live streaming. We only stream to YouTube. While we do have MS Office installed, it is shut down during our live-streaming. We use Firefox as our browser and only one tab is open, which is for YouTube Studio. OBS shows about 10-12% CPU usage during our live streaming.

Our laptop is about eight months old and I believe that I have deleted or disabled all unnecessary options, which I review after each windows update. We do not run any "eye candy" or the like. It is regularly "cleaned up". All Windows automatic updates are turned off - I check manually.

We are up to date with NDI tools and the NDI plug in.

I believe that I have the most advantageous firewall settings, but I am sure there are more tweaks that I could still learn about.

We used to use two iPhones for our live streaming and we had no syncing issues.

 

[Lawrence_SoCal]

OBS shows about 10-12% CPU usage during our live streaming.

OBS is only showing a small portion of actual CPU usage (and I find to be near worthless as a stat)
I recommend monitoring full system hardware resource (CPU, GPU, RAM, etc) utilization [for ex. using Task manager’s Performance tab and/or Resource Monitor] to look for bottlenecks

 

[VSW]

Thanks for your reply.

The audio was a bit better in our last live stream with less drift.

I monitored everything again, including through Task Manager. There was no significant processes using up resources. In fact, there was plenty of overhead remaining for CPU, GPU, memory, etc. I have previously and carefully disabled various processes/services that were not required.

So I am still baffled as to what would cause the audio to drift. Both our PTZ cameras are the same model with the same settings. Both remain active throughout our streaming.

Anyway, I continue to research and look for solutions.

 

[InfluxxMedia]

please send an OBS log what says the Network Bandwitch when 2 cams on ?
when the bandwitch is very high use more network interfaces NDI support to use mutiple Network devices.

i had the problem i use a stream PC and the cams are on my stream PC so i Transfer my cams to my Gaming PC to use in Discord and other softwares and my gaming PC sends the Desktop to the Streaming PC when i stream over twitch i had bandwitch problems so i had add a second network card only for OBS output and it works on the limit !
next step on my NDI setup is to change to 10gbs network over SFP cables

Jeez learn to use some punctuation. Your message is complete gibberish.