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DecklinkSDI audio drop outs

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John Robinson
DecklinkSDI audio drop outs
on Dec 21, 2010 at 4:26:41 am

I am hoping someone can help us figure out this audio problem.

We recently set up a Decklink SDI on a new Mac Pro in order to ingest material from our SRW-5800 and lay off to fresh tape for tape for duplication/dubbing purposes. We are using pro-res compression on a 4 drive sata raid.

The Decklink machine and the SRW both receive HD-Blackburst, but for some strange reason, we get random audio dropouts on the SDI path to tape every time we try to layoff. The puzzling part of this is that the video looks great... just random audio "pops" about every 30-50 seconds.

I've talked to black magic, sony, and several final cut "gurus" and so far no-one can offer us any definitive solutions. My suspicion is that we're dealing with some sort of digital sync issue, but as of yet there seem to be too many variables in the equation.

I'm hoping others have experienced similar conditions and could advise us. Thank you,


John Robinson

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Robert Dewerff
Re: DecklinkSDI audio drop outs
on Oct 13, 2011 at 8:41:54 pm

We are seeing a similar problem on some of our machines: We are seeing random audio blips/spikes equipped with BMD Decklink SDI or Studio 2 cards. There is normally a drop in video frames (a few frames of black) associated, but not always. Sometimes the audio blip has a high pitched chirp tone as well. When looking at the SDI input feed with media express, we can see the audio levels on embed channels 1 and 2 peak out at max. Occasionally we are see levels across channels 1-8. We are noticing these issues when the source is NTSC or PAL (no symptoms with HD-SDI formats)

We have one location with 6 encoders connected to a BMD Router. When multiple encoders are patched to the same source, they are all experiencing this anomaly at the same moment. This should eliminate the possibility that the issue is being created/manifested at the card itself.

Some sources types are worse than others. Most of the situations we are experiencing this have an a source that originates at a Satellite IRD, though we have seen it with Xserve.

We are currently using the new 8.6 drivers, but have had the same issue with 8.5, 8.01, and 7.93

Any ideas, suggestions, or verbal beatings would be appreciated.

Bob D
America One Networks

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