Roland Edirol V-8 latency problems

[CFMMEDIA]

We recently just purchased a Roland Edirol V-8. We are currently using an IMAC and running pro presenter as our presentation software.

We are experiencing a few latency problems in our videos played from the iMac with audio and video not in sync (little delay) since we added the Roland V-8 in the loop. Didn't have this problem when we ran iMac directly into switcher/scaler. But now that we have added the Roland V-8 there is a delay! Any suggestions out there? Do I need a distribution amp between Roland V-8 and switcher? If so any recommendations?

Thanks,
CFMMEDIA

[waynehoskins]

Anything that retimes the video will introduce at the very least 1 frame of delay, which is 1/30 second. The V8 with its built-in frame syncs does this, as does your scaler. Most add more than one frame, more like 2-3. By introducing the V8 in the chain, you've likely doubled the processing delay.

The only way to have no delay from input to output is to use a broadcast-grade system with no transcoders in the middle. However, since it's only for playback, two possibilities come to mind:
1. Take the V8 out of the chain.
2. Delay the audio so it's in time, using something like a Rane AD22, a two-channel audio delay. There's a version that's calibrated in frames, and I think it has "AVA" in the model, an "Audio-Video Alignment" delay.