Audio output lost after a while (hours to a day)

I’m trying to output mp4 clips via Blackmagic i/o card
everything works perfectly for a while, after a few hours (possibly a day) - the audio stops playing,
video still playing, but all outputs of the blackmagic have no audio.
I restart the casparcg server, reload the clips and the audio works again for a while till it happens again,

what would be the right way to start debugging that?
it’s different clips everytime, all 3 outputs I use stop providing audio at once


Are you running in 50 or 59.94?
What version of CasparCG?

How does the DIAG window compare between the audio working and not working?
Anything in the logs?

Hi Julusian, thanks for the quick reply!

I couldn’t find any errors in the log prior to the audio stopping,

When I noticed the issue I shut down the casparcg server,
in the log it says:
[2023-07-31 13:27:25.647] [error] DeckLink Duo 2 [3-3|1080i5000] Failed to schedule audio.
[2023-07-31 13:27:25.647] [info] DeckLink Duo 2 [3-3|1080i5000] Scheduled playback has stopped.

but I don’t know if it’s normal, might be a normal shutdown behavior (?)

there’s another warning a few hours earlier but I’m almost sure the audio worked after that:

[2023-07-31 06:52:43.122] [warning] DeckLink Duo 2 [4|1080i5000] in-sync changed: -0.556896
[2023-07-31 06:52:43.170] [warning] DeckLink Duo 2 [4|1080i5000] out-sync changed: 0.02
[2023-07-31 06:52:43.205] [warning] DeckLink Duo 2 [4|1080i5000] out-sync changed: 0.04
[2023-07-31 06:52:43.644] [warning] DeckLink Duo 2 [4|1080i5000] out-sync changed: -0.158021

do you think that those messages contain any valuable information?

I am not sure if that is normal or not, I suppose it could be depending on timings.

If it was only a couple of log lines then I don’t think there is anything to worry about there.

What decklink driver version are you using?

I’m using Blackmagic 12.5.1 with a Decklink Duo2 card at 1080i50

I’m running CasparCG server 2.3.2

is there a recommended version for casparcg/decklink drivers?

I have had similar audio issues in the past caused by unstable Genlock. (Blackburst/TriLevel). Do you use Genlock ? If yes, try without or try changing from TriLevel to Blackburst if possible.

Hi Dirkdamerau,
We have 2 machines, one with genlock, the other without
it happens on both, I’m not sure it’s genlock related…
I can tell you that the switcher that the SDIs are connecting to is shutting down every day,
Not sure if this could cause such a behavior

I don’t think a mixer shutdown has to do with this as SDI is unidirectional. But to be sure just leave the mixer running for a few days.

yeah, I guess you’re right,
I have no explanation for that,

after a few days of work I can say that we still lose audio after 15-20 hours since startup,
restarting caspar server solves the issue for an hour or two,
Rebooting the whole machine fixes it for the next 15-20 hours

Any ideas would be much appreciated

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