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Intensity Pro bad audio

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Rodney Rushing
Intensity Pro bad audio
on Aug 27, 2009 at 4:35:02 am

When I am capturing from my Intensity Pro card using the provided Media Express app, the audio is completely distorted. I captured a raw AVI and extracted the audio, and I can see what looks like the waveform is DC biased off the chart.

Also, sometimes without anything connected to the input it clicks at me like once every half second. Then sometimes it almost works - it gets clipped a tiny bit, but most of the signal is there and just sounds a little fuzzy. I can't find the pattern though. I thought it was the drivers because I uninstalled, cleaned the registry and the driver repository, reinstalled, and it worked, but then the next try was totally off again.

With my "lesser" TV capture card this all works perfectly.

Help!

- Rod


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Rodney Rushing
Re: Intensity Pro bad audio
on Aug 27, 2009 at 7:11:09 am

Oh dear. I was trying different settings when all of a sudden it started screeching at me, even if I unplug both the audio and video cables or restart the application:



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Kristian Lam
Re: Intensity Pro bad audio
on Sep 1, 2009 at 10:40:48 pm

Could be a bad card. Have you contacted tech support? They will be able to sort you out.

regards

Kristian Lam
Blackmagic Design


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Rodney Rushing
Re: Intensity Pro bad audio
on Sep 10, 2009 at 5:35:41 am

Not yet. It didn't go so well when I called in about composite video not working. And, their work hours are my work hours, so I have to find just the right time to hang on the phone for a long time. I thought I'd try here first this time.


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Sean Sullivan
Re: Intensity Pro bad audio
on Sep 10, 2009 at 2:43:46 am

It looks to me like the audio you're trying to record is too loud. I don't know of an interface to adjust the volume of the card's audio input from your pc, but maybe you could adjust the volume on your source's output?


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Rodney Rushing
Re: Intensity Pro bad audio
on Sep 10, 2009 at 5:43:15 am

When it works, you are correct, the output is being clipped. But these are consumer video player outputs, there is no volume control. I find it odd that this pro equipment can't accomodate the signals from these devices, but everything else can.

The bigger problem is not volume. If you look at the waveforms, one is operating above the clip level and occassionally dips below. the other is a screeching/whistling type sound that is completely unrelated to the audio source - I can unplug the audio source, restart the application, and it's still there.


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Rodney Rushing
Re: Intensity Pro bad audio
on Oct 4, 2009 at 4:04:23 pm

FYI - As an experiment I sent the audio through a simple voltage divider resistor network and while the signal was sufficiently below the limit, the distortion was still there - looking closely there is actual noise in there at a higher frequency than the audio (some stuff was at or greater than the sampling rate.)

I since updated to the newest drivers and ran Media Express v1. The audio sounded clean and completely different; this signal has a clean sinusoidal look to it. But, the program I want to use still has the horrible sound.

I think the root cause is the drivers.


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