Hi,

We're having the same issue here.

We're using Black Magic Quad Card with 2 HD-SDI inputs which carry embedded audio. We output over HD-SDI to a BM decklink Studio card to a Pix240 recorder.

Over the course of a 2 hour test, we had around 11 dropped frames and probably about as much (11 frames) audio drift. The info button said that the drops were due to the source frame rate (for the decklink output, the vmix virtual output claims no dropped frames). All of our sources are from the same 1080p29.97 inputs. Is there anything that we can do to get rid of the drops? If the delay in audio is in fact being caused by the dropped frames is there a way to make the audio and video stay in sync even when the frames are dropped (as in drop the frame of audio as well)?

We just upgraded to the trial of vmix9, we were hoping it would solve this issue. Let me know if I can provide any more info!

Thanks!

Dan

Hi Martin,

My issue is not with local recording to VMIX, it's actually over the decklink render to SDI which is being recorded to a pix240 video recorder. I am happy to do the experiment for you, but will there be a log file generated if I don't record locally? I am only ouputting via decklink out and vmix virtual camera.

Edit:
I ran a 3 hour test, then pulled the final files into final cut pro to look at how many frames of drift we had:

Output via decklink 1080p29 recording onto pix240 recorder HD-SDI
00:00:00 - no drift
00:45:00 - 3 frames audio lags behind video
01:38:00 - 5 frames audio lags behind video
02:45:00 - 11 frames audio lags behind video

Downloaded file from livestreaming service (new.livestream.com), vmix video is the video source, system mix is the audio source (can't choose vmix audio for "livestream for producers"). This is the file that was recorded on the server:
entire video (3 hours) the file's audio was consistently 5 frames ahead of the video
- is there a way to make "live stream for producers" to recognize the vmix audio as a source? It only sees the system mix and default audio device. I wonder if this would allow to introduce a 6 frame audio delay? Other ideas? So far in playing with the audio delay feature under external output, I've had no luck getting any kind of delay to effect either my SDI output or my virtual vmix cam output.

There were no log files produced that I could see. We also dropped about 6 frames right when we started up (for the decklink output) but then never reported dropping any more frames. let me know if I can recover them somewhere and send them along. And THANK YOU for your help!

Dan