VirtualDub drops the brightness by 10 IRE during the capture

[Hypersonic1]

After capturing a video, only the first few seconds plays above 100 IRE and then it drops below to about 90 or 95 IRE no matter how bright the subsequent scenes are, regardless of what I set the levels at. This is an irritating problem for me. I have a Diamond VC500.

[Hypersonic1]

Actually, it seems to do this in other software too. I don't know why it does this.

[jagabo]

VirtualDub isn't doing that unless you've added an AGC filter to the capture chain. Check your capture device's proc amp settings and disable any AGC (and all other filtering) function.

[Hypersonic1]

The proc amp settings are at 5000, 5000, 5000, 0. That's the default. I don't have anything in my chain, just a AG-1980 or Sony TRV-350 attached to a VC500. The brightest part of a scene starts at 110 somethings for a few seconds and then it never goes above 100 after that. It appears to be dynamic. It does this on the USB Live2 and the VC500. I would like to think it's just the recorded tape, but I had these videos digitally-converted by a company (dissatisfied with the results), and they didn't have that issue. There are 110 IRE parts all over the video with the same video clips. They could have adjusted the levels in post, but I don't know why they would keep the whites above 100. They appear to have not adjusted the levels.

[jagabo]

So there's not "auto" column next to the other proc amp settings? Here's a typical proc amp dialog in Windows with the auto column:



If that's the case maybe the VC500 always has the AGC enabled. Start capturing a few seconds earlier and trim the unwanted frames away.

[Hypersonic1]

[Attachment 44199 - Click to enlarge]
The auto's are all greyed out.

I tried capturing several minutes before, but it doesn't seem to lower it until shortly after a clip goes above 100 IRE.

[Hypersonic1]

I uploaded a couple examples to show the difference.