Quantcast Proc Amp Use Cases and Guide - digitalFAQ Forum
07-17-2019, 11:40 AM
will74 will74 is offline
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Thanks again in advance for the incredible information and help you've given me with this forum. After much time of acquiring equipment and putting this off for various reasons, I have recently received my JVC HR S7900 from lordsmurf to complete my setup of JVC HR-S7900 VCR>AVT-8710>(sometimes) SignVideo PA-100 >ATI AIW 9200 to Huffyuv AVI in Virtualdub.

I've started to capture some tapes and things have gone well so far. I have done most of the tapes without the proc amp, but on a few, i've connected it up and played around with the black and gain settings to make a few adjustments.

That said, I'm trying to figure out how and when to use the proc amp.

I looked around this site (and the internet in general) to try and find a guide beyond the manual that comes with it, but couldn't find anything.

Here's what I've been able to figure out:

-I know that the hue and saturation adjustments are in almost all situations (outside of a color cast over the whole video) better done in post.

-I know that for this type of work, a really good, calibrated display is important. I have a decent IPS screen that has been calibrated with an X-rite calibrator, so it's pretty much the best i'm going to get.

-I also know that the IRE meter on the PA-100 can be very useful for keeping things within the viewable/legal limits.

I have read that you're trying to keep the histogram value in Virtualdub between 16-235 (inside the red areas on the side). Is that correct?

I know that it can be difficult to adjust these levels during capture since scene to scene the lighting can be drastically different and the histogram doesn't show up during capture. I think that this is where the IRE meter comes in. I can use it to adjust the luminance levels to avoid signal clipping in real-time while capturing. I also think that I read somewhere that you want to keep things in the IRE meter between 7.5-100, because there's a point below 7.5 where the capture doesn't really get anything from a 5 IRE and below. Is that correct?

Overall, when using the Proc Amp, are you trying to keep the levels between the low IRE (7.5 or whatever is the answer to my question above) through 100 without clipping?

Is another goal to try and fill the meter in the PA-100 for every scene from the low IRE through 100 without clipping?

Additionally, I know from doing some other video work, that for a video that you want to use to color grade/make adjustments in post, people often recommend capturing it in a "flat" profile on the digital camera, to give the most latitude for the edits later. When making any adjustments with the proc amp, should a "flat" output be the goal?

And finally, related to the above, as far as I can tell, when I've been able to capture successfully, I've used the "Overlay" option in Virtualdub, because I've had problems with CPU use (I think, although maybe I should try this again) causing audio sync issues when using the "Preview" option. How do you view the capture as it's happening? Is there a way to break out the signal to a separate monitor (without harming the signal going to the capture card) Or is there another method to view the video live while capturing? Or is the only option to do it the way I have been doing it, by using Preview to get to my starting point, then switching to Overlay right before I start capturing, and trying to use the sound from the video that's playing to tell when I need to stop capturing.
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