Capture: VHS-C camera, live, via USB device OR Sony PD150

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dmcconville

New member
Hello all! Thanks for having me on the forum!

I am helping a friend to capture some footage; helping because I own many old formats, converters etc.

We're capturing live footage through a JVC gr-ax280 - we like the CCD sensor and the lens, it's got a look we enjoy.

When capturing through a cheap USB capture device, or through my Blackmagic Analog to SDI / Mini Recorder, there are lines present on the capture.

Laced, scan lines. Digital artefacts, I guess.

However, when I use Firewire instead, via my Sony PD150, those lines are not present.

The image without them is much more pleasing to us.

I'd prefer not to have to continue daisy chaining cameras to get the result, so would like to find another solution.

But I can't understand why we're getting such different results. If anyone has any ideas on what could be causing each outcome it would be super useful!

Thank you!

TigerD
 
When you daisy chain through your PD150, composite to Firewire the signal goes through a two-line TBC stabilizer that restores correct H & V Syncs to the firewire output to enable a good solid signal for Firewire capture. It also locks the audio signal frame by frame to the leading edge of line one's sync pulse of each frame. Thereby maintaining constant audio/video sync as the transfer or playback takes place. This two-line TBC was designed to correct any tape wow, flutter, and phase jitter of the Mini-DV tape when it was in playback mode. This very basic TBC function is also active when doing composite to Firewire transfers. On the other hand, the BM Analogue to SDI Mini Converter is expecting to see an already stable timebase corrected signal at its input, like an EE signal from a camera for example. The mini-converter requires an input signal without any H & V Sync or jitter inconsistencies to be able to achieve a good stable output signal. I would strongly suggest that this is your issue. Beg, borrow or steal an old TBC with a Proc Amp in it if you can. That way you will get a stable output with the ability to adjust the black level, chroma, and video levels in realtime as the signal is being processed. We often used to successfully run unreferenced recordings like VHS etc through a studio deck like an SP Beta or DVC Pro deck and process the pass-thru signal by using the deck's inbuilt TBC and Proc Amp. Good luck.

Chris Young
 
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