At our church I have multiple PTZOptics 30X NDI|HX cameras feeding to OBS that streams to Facebook. Two weeks ago someone complained the sound was not synced with the video. When reviewing the service Facebook live recording I noticed in the middle of service suddenly a >1/2 sec delay of video from audio. The next Sunday during service it happened again. This time we noticed during the service. What we saw was one camera on the Program screen was synced to audio and an other camera on the Preview screen had ~1/2 second delay from the audio. You can notice the different hand gestures in the attached image of the pastor. With other cameras and computer this use to happen really bad sometimes ( >7 seconds). This is now happening with new cameras and high end computer. When troubleshooting the next day I noticed all cameras virtually in sync at the start. Latency setting = Normal and sync = source timing. I changed the sync = Network on all cameras and Latency = Low on only two to the three. Went to a meeting and after noticed the one with latency = normal had a delay again. Is Latency = Low the main fix? Is there a way to reset delays mid-broadcast if this happens again? What is the difference in the Sync settings (Network vs Source timing)?
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
How do I prevent different video latency between multiple NDI HX PTZ cameras?
- Thread starter mjbusta
- Start date
Lawrence_SoCal
Active Member
This really is a question for PTZ Optics and/or NewTek (maker of NDI Tools).
Fortunately, I've not dealt with this issue on my HoW NDI PTZ camera. My initial thought is PC 'horsepower' but if truly adequate (and something worth confirming, vs assuming)...
- Do you have all cameras sending same frame rate, video encoding, etc?
with a single camera, I had no issue with letting camera at default of 1080P60 and letting OBS drop Recording and Streaming to 30fps. TO keep system load reasonable, I'd recommend making sure cameras sending same. And if you aren't using 60fps, and cameras support being configured for 30, I'd do that (but test)
- I don't have PTZ Optics, but just in case similar, presuming you are using House mixer, vs audio routed through camera, have you disabled Audio on the cameras (or made sure disabled at Operating System level)?... no shouldn't really be an issue, but safer than sorry??
- have you confirmed NDI camera feeds being decoded by GPU/iGPU decode chip, vs CPU?
- You ignored pinned post in this forum and didn't post OBS log.. DO you have a GPU to do video encode offload?
The sync settings you mention, are not in OBS right? Are you setting that in PTZ Optics's OBS tools/plugin, camera web interface, or ??
There may be an advanced setting for the PTZ cameras to make sure cameras all time syncing the same. That would be PTZ Optics specific config (though may require network config to support).
Your NDI cameras hopefully are on an isolated network (physical or VLAN), not shared with church office, guest WiFi, etc. If not, start there
Fortunately, I've not dealt with this issue on my HoW NDI PTZ camera. My initial thought is PC 'horsepower' but if truly adequate (and something worth confirming, vs assuming)...
- Do you have all cameras sending same frame rate, video encoding, etc?
with a single camera, I had no issue with letting camera at default of 1080P60 and letting OBS drop Recording and Streaming to 30fps. TO keep system load reasonable, I'd recommend making sure cameras sending same. And if you aren't using 60fps, and cameras support being configured for 30, I'd do that (but test)
- I don't have PTZ Optics, but just in case similar, presuming you are using House mixer, vs audio routed through camera, have you disabled Audio on the cameras (or made sure disabled at Operating System level)?... no shouldn't really be an issue, but safer than sorry??
- have you confirmed NDI camera feeds being decoded by GPU/iGPU decode chip, vs CPU?
- You ignored pinned post in this forum and didn't post OBS log.. DO you have a GPU to do video encode offload?
The sync settings you mention, are not in OBS right? Are you setting that in PTZ Optics's OBS tools/plugin, camera web interface, or ??
There may be an advanced setting for the PTZ cameras to make sure cameras all time syncing the same. That would be PTZ Optics specific config (though may require network config to support).
Your NDI cameras hopefully are on an isolated network (physical or VLAN), not shared with church office, guest WiFi, etc. If not, start there
nelsonlvidoes
New Member
I have the same issue sometimes. Last Sunday audio/video sync on one camera was off by a second but the other two were ok. I have a beefy computer and my latency is 1 ms or less when I ping all the cameras? Most times it works ok. I have a gig switch to connect 3 computers and 3 cameras and that is all on that switch. Rebooted between class and worship and all were back in sync?
Lawrence_SoCal
Active Member
Upper end cameras have a GenLock feature to keep things in sync (broadcast level feature).
Presuming you have Standard (not GenLock capable) NDI cameras, then, depending on camera, I'd be inclined to make sure NTP working correctly on network, and get into habit of 'rebooting' the cameras weekly.
We usually, but not always, put camera into Standby mode after service. *if* we find we forgot, and find camera powered up from prior week, then we put it into standby and take back out. And, of course, I do NOT leave streaming computer logged in/standby/hibernate. We always shutdown PC after service, and fresh OS boot day a few hours before service/stream
After many decades of experience, I'd never trust Windows OS Standby/sleep/hiberate for anything important. And I've been in the habit of shutting down daily for same decades, for reasons, and recent experience only confirms why it is still a good idea. Is a full reboot required? no, but 99% of folks don't have the expertise to follow the steps necessary, so a reboot is usually simply quicker & easier instead. And there are some circumstances that require a reboot, especially with poorly written consumer apps and drivers.
- And then there is best practices/hygiene of making sure no malware gets onto those 3 computers, that many do no follow that can cause complications.
- And hard to know if you weren't doing real-time network monitoring at LAN level (which almost no one does, understandably).
- And, as for 1 camera audio/video being off sync? personally, I prefer to use House mixer/mics, and NO camera audio, at all...ever. So, are you using camera audio for some reason? or did you mis-type, and issue was 3 cameras video not being in sync with each other [1 not being in sync with other 2 in your case]?
Presuming you have Standard (not GenLock capable) NDI cameras, then, depending on camera, I'd be inclined to make sure NTP working correctly on network, and get into habit of 'rebooting' the cameras weekly.
We usually, but not always, put camera into Standby mode after service. *if* we find we forgot, and find camera powered up from prior week, then we put it into standby and take back out. And, of course, I do NOT leave streaming computer logged in/standby/hibernate. We always shutdown PC after service, and fresh OS boot day a few hours before service/stream
After many decades of experience, I'd never trust Windows OS Standby/sleep/hiberate for anything important. And I've been in the habit of shutting down daily for same decades, for reasons, and recent experience only confirms why it is still a good idea. Is a full reboot required? no, but 99% of folks don't have the expertise to follow the steps necessary, so a reboot is usually simply quicker & easier instead. And there are some circumstances that require a reboot, especially with poorly written consumer apps and drivers.
- And then there is best practices/hygiene of making sure no malware gets onto those 3 computers, that many do no follow that can cause complications.
- And hard to know if you weren't doing real-time network monitoring at LAN level (which almost no one does, understandably).
- And, as for 1 camera audio/video being off sync? personally, I prefer to use House mixer/mics, and NO camera audio, at all...ever. So, are you using camera audio for some reason? or did you mis-type, and issue was 3 cameras video not being in sync with each other [1 not being in sync with other 2 in your case]?