Odd audio error "message".

farss wrote on 6/14/2008, 4:18 PM
Captured A/V over firewire from a device that is known to be faulty.
Vision looks OK, audio shows up on the Vegas T/L as nothing, not even a flatline waveform, Vegas cannot even decide if it's stereo and where a waveform should be is just solid red.
But it plays back and sounds like garbage.
Open it in SF and there is a waveform, in stereo as it should be. It still sounds like garbage of course. By the sound of it there's very serious sample rate errors.

This suspect piece of hardware has come my way because it doesn't work right on Avid systems either with similar audio problems.
It seems to work OK with DV Rack but I need to test this more carefully to be 100% certain.
We've previously shipped the untit back to the manufacturer in the USA and they tested it on FCP and returned it claiming nothing wrong with it. We have around another 10 of the same units here in Australia and all work perfectly with Avid and Vegas.
Clearly something is wrong with it. Before we incur the considerable cost of shipping it back to the USA again I'd like to have a more definative fault description. Knowing why Vegas displays the captured DV's audio as just red could be very helpful in my quest.

Bob.

Comments

Widetrack wrote on 6/14/2008, 7:16 PM
Ugh. not a great situation. But there may be a solution.

If you can play the video on the A/V device you have, or any other one on which the audio sounds ok, I think your best bet is to forget about capturing your audio via firewire. Instead, play back your tape and record its analog audio output in Vegas via your audio interface. If it sounds ok as you play it, and your audio interface is ok, this should be a snap. After recording, you ought to be able to line up the audio with the video in Vegas with a little careful adjustment.

try to keep the peak level of the audio at about -9 dB. but above all, keep the signal from hitting 0 dB, as this will cause ugly digital distortion. Unless your audio contains a lot of bad background noise, you should be able to normalize the audio signal after recording it in Forge or any other audio editor.

good luck.
farss wrote on 6/14/2008, 7:22 PM
Sorry but I'm not worried about trying to recover the audio. I'm only using standard BBC test tapes. I'm trying to diagnose what's wrong with the hardware (SDI to firewire converter) before I send it back to the manufacturer.

Bob.
musicvid10 wrote on 6/14/2008, 9:55 PM
Uh Bob, sorry to overstate the obvious, but you haven't identified the problem "device" other than in the most generic sense, so none of us can have a clue as to what to steer clear of. Care to enlighten?