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frustrating sync problems between cameras
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Joined: 3/20/2020(UTC) Posts: 29 Location: Oregon Thanks: 1 times Was thanked: 4 time(s) in 4 post(s)
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In short, I have three PTZ Optics NDI cameras. After time (varies from a few to 20 or 30 minutes or so), the cameras get out of sync. I need to find a solution to this.
The details: - Core i5-8600 6 core, 16GB mem, NVMe SSD, Quadro P2200, Intel Gb ethernet - Intensity Pro 4K capture card - three PTZ Optics 30x NDI|HX cams (inputs 1-3) - HDMI capture from second computer (input 4) - less than 6 total additional overlays, titles, images, etc. - Ubiquiti Switch 8 60W (Gb) connecting it all and powering the cams - Longest ethernet run is ~150', Cat6 shielded - Cams set to NDI Medium with no changes to defaults (1920x1080p/30) - hardware accel enabled everywhere - problem exists even when encoding to one source (facebook) - task manager shows VMix less than 40%, VMix agrees - Rebooting the cams fix it temporarily - Closing and re-adding them to VMix fixes it temporarily - Trying out OBS to see if the problem follows
I'm at the point of closing and re-adding cameras multiple time while live to fix the problem. It's getting stressful because there are a few things that need to be done to the cams before each is live and some of the XKeys functions don't work when you do this until after restarting VMix.
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Rank: Advanced Member
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Joined: 4/23/2017(UTC) Posts: 1,210 Location: Germany Thanks: 3 times Was thanked: 168 time(s) in 150 post(s)
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I have no immediate solution but you could waste a thought on using RTSP instead of NDI and see if it's the same there. Second you can also test with the NDI ISO recorder if the cams are drifting apart there as well. Just to narrow it further down to identify the root.
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Rank: Member
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Joined: 3/20/2020(UTC) Posts: 29 Location: Oregon Thanks: 1 times Was thanked: 4 time(s) in 4 post(s)
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I tried adding them as rtsp. There is a larger delay in the video feed, but all the cams seemed to be in sync. However the delay seems to increase over time which is simply unworkable. I can close and re-add a single cam after 15 mins and it’s way off the other two cams which are still in sync.
I’ll try the iso recorder.
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Rank: Advanced Member
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Joined: 4/23/2017(UTC) Posts: 1,210 Location: Germany Thanks: 3 times Was thanked: 168 time(s) in 150 post(s)
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This sounds to me that it more a cam issue. I would expect the cams drifting apart even in the ISO recorder. I don't know the PTZoptics products very good. Maybe there is a chance to let them rync against something. Genlock or NTP.
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Rank: Member
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Joined: 3/20/2020(UTC) Posts: 29 Location: Oregon Thanks: 1 times Was thanked: 4 time(s) in 4 post(s)
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Coincidentally I enabled ntp yesterday. Didn’t have much hands on testing time though. I left the three cams open in OBS and they stayed in sync for over an hour. Wasn’t streaming though. Will test more today under a bigger variety of scenarios.
What’s genlock?
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Rank: Member
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Joined: 3/20/2020(UTC) Posts: 29 Location: Oregon Thanks: 1 times Was thanked: 4 time(s) in 4 post(s)
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So far enabling NTP has seemingly solved this. I still reboot the cams before each event, which is about a 1 hour church service. I looked up GenLock and PTZ Optics do not support this feature. So I'm guessing they have some exceptionally bad internal clocks. I asked them, Once NTP is enabled how often do the cams query the time servers? but didn't get any info back.
Anyway, just wanted to follow up.
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Rank: Advanced Member
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Joined: 4/23/2017(UTC) Posts: 1,210 Location: Germany Thanks: 3 times Was thanked: 168 time(s) in 150 post(s)
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Rank: Member
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Joined: 3/20/2020(UTC) Posts: 29 Location: Oregon Thanks: 1 times Was thanked: 4 time(s) in 4 post(s)
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I feel confident in posting I have an actual solution to this. NTP wasn't it. In short, PTZ Optics released a firmware update and for the last two weeks I have not experienced the cameras getting out of sync. I haven't even restarted anything this last use outside of opening VMix. The computer, cameras and network switch have all been on for the last week. I'm on firmware 6.3.12. I was on 6.2.84 previously, so there have been a couple firmware versions in between that could have solved the problem. Their changelog doesn't indicate anything that looks related, but I've only been able to get through a church service one other time without having to close and re-add cameras multiple times in a one hour period of use. The hours I've lost to troubleshooting this, the upgrades, the hardware swaps... So, if you use PTZ Optics NDI|HX cameras, you probably want to be on firmware 6.3.12 or newer.
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Rank: Newbie
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Joined: 6/24/2021(UTC) Posts: 2 Location: Cape Town
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Thanks for posting that NTP wasn't the solution. I saw your original post a few months back when I was trying to troubleshoot cameras going out of sync and as a result of one of your posts I pursued NTP syncing as a solution, going so far as to hack my NDI hardware encoders to get it working. In short NTP sync wasn't the answer for vMix (although it did have an effect in another app I tested with).
The NDI SDK documents specifically talk about NTP-derived timestamps in streams as a good idea/necessary for syncing, but in practice that doesn't seem to be the case.
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Rank: Advanced Member
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Joined: 4/23/2017(UTC) Posts: 1,210 Location: Germany Thanks: 3 times Was thanked: 168 time(s) in 150 post(s)
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If the firmware update fixed it it was then more an internal issue and nothing outside. Thanks for providing the info.
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Rank: Member
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Joined: 3/20/2020(UTC) Posts: 29 Location: Oregon Thanks: 1 times Was thanked: 4 time(s) in 4 post(s)
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Yep, definitely firmware. And as a further follow up I haven’t restarted the switch or cameras in some time. They get restarted now and then for other reasons. I am very confident with the sync in our three cameras now. Zero concerns there.
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1 user thanked mikesg for this useful post.
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