Hi all, long story short I’m building a multimedia playback rig for our webcast productions and decided to use the NRK fork of the server since it seems to handle audio sync with system audio a lot better than 2.2.x or 2.3.x, with which the audio will drift out of sync over time. However none of the client versions I’ve tried don’t seem to work perfectly with NRK server, I noticed that on some client versions there’s no time display on the rundown items and some videos stop a couple of frames before the video actually ends, therefore preventing auto play of groups (video gets stuck before transitioning to the next one).
I tested the SuperConductor Client posted here recently and it handles playback flawlessly, so it seems that the server is not the one causing the problem?
Why not just use SuperConductor then I hear you ask? Maybe we will in the future, but for now it lacks some of the functions of the official client so I’d rather have that also just to be safe. So does a client for the NRK fork even exist or am I chasing ghosts here?
And 2.0.7 or .8 is unfortunately not an option since our html graphics don’t work on them.
Thanks for your reply. Playing back a 25p file through a 50i decklink consumer should work no problem, right? From what I’ve read and seen it seems that the decklink consumer and system-audio consumer will drift out of sync over time no matter the frame rates.
What is your “over time”? minutes, hours, days, weeks, years
Is the drifting constant (for all framerates)
and you said you are taking the audio from “system audio”, is that DVS, a USB-soundcard or pc-3,5mm?
these are all question that can help us better understand your problem.
Usually I think most users here use embedded audio in SDI and those who need analog audio uses a Decklink Extreme-card that has analog audio out.
My signal flow for testing is like this:
Ch 1 video → decklink consumer (1080i50) → SDI out → SDI monitor
Ch 1 audio → PCIe sound card (ESI maya44) → 4ch yamaha mixer → speaker
I need to be able to send the audio to an audio mixer for routing purposes.
I don’t know if the drifting is constant, I can only measure it by playing a sync test video in caspar, pointing a camera at the monitor and recording it. First test was with 2.3.3 LTS, I played a 2hr seminar recording (25fps progressive) and towards the end I started to notice audio going out of sync. Then I used a 50p sync test video to measure the diffrence, and audio was 12 frames behind video. After restarting the server and measuring sync audio was 6 frames behind video. I let the sync test run for an hour or so at which point the audio had drifted further behind the video but I can’t remember the exact amount.
Writing this out I do realize I haven’t been very thorough with my testing and the test video I used was 50p instead of 25p.
Then I tried using the NRK fork, let the 50p test video run for 4 hours and didn’t notice any drifting, but any of the client versions I tried didn’t work 100% and now here we are.
You could try to run a longer clip (1-2 hours) and compare the audiosync between your audiocard and the audio from the monitor. If the audio from the monitor is in sync with the video the it something related to your audiocard.
If you compare the audio-specs in the videofile (with Mediainfo) are they the same as your system-audio-settings in windows?
I don’t know how your audiocard get’s synced I don’t think it takes it from the Decklink so my best guess is from the graphics card, normally 60hz.
At SVT we use 2.3.3 as video server for the tre largest controll rooms and for a lot off other chains and I nerver heard about syncissues.
The best solution is to use a deembedder to get the correct audio from the sdi where the video lives, they like to stay together.