ATI USB 600 Brightness

[theseeker2]

I'm capturing using my JVC HR-3900U VHS VCR and an ATI USB 600. Can anyone else out there who has a ATI USB 600 tell me what the default brightness setting is on the built-in proc amp? My adapter is currently set to 100 brightness, but it looks like 128 would be closer to the defaults. I've tried playing around with the contrast and brightness using the histogram in VirtualDub, but I've read so much conflicting stuff on whether that's worth my time that I'm leaning towards using the defaults apart from turning the sharpness down to 0. Although I will say that typically the pictures look more "natural" to me when brightness is at 100 rather than 128.

Any wisdom from other ATI USB 600 users would be much appreciated! Thank you.

[theseeker2]

Here are two captures, the first is with brightness at 100 and contrast at default, the second with brightness at 100 and contrast turned up a bit. I'd appreciate any feedback as to which you think is better.

If you'd rather do an image slider comparison, here it is: https://imgsli.com/MTk5Mzc5.

[davexnet]

It's not possible to know from those two images. You should review the footage before and after to try and figure out if that
is representative of the footage or not. Rather than raise the black level, perhaps increase the gamma a little

[theseeker2]

Thanks for chiming in. I feel like the raised constrast version brings out a few more details but also washes out some things (like the mic on the left). I guess it's always a trade-off, isn't it?

[theseeker2]

@Skiller, @lollo, @Sharc, any opinions on the two images above?

[Sharc]

I share davexnet's comment.
Based on that single frame I would say the levels are ok, just raise the gamma a bit (say from default 1.0 to 1.05 .... 1.1) which will expand the darks. Do it in post (avisynth) rather than fiddling again with the proc amp.

[theseeker2]

So the contrast up version (second frame) isn't really an improvement? It sounds like whether the contrast is flat or up, I can just make some gamma adjustments in post and I'm good?

I'm grateful for you all weighing in, thanks again.

[Sharc]

Yes, gamma correction should be fine to bring out more details in the dark.
But first, as has already been said, one cannot draw final conclusions just based on a single frame. You have to check the captured video using the histogram and/or waveform monitor for various scenes. Then make your choice what corrections (if any) to apply in post processing. Plenty of posts exist in this forum how to do this in avisynth.
And second, trust your own eyes and personal preference. There is no absolute truth.

[lollo]

Upload a video sample rather than a fixed image.
Do not play too much with the procamp of the card. Just be sure that you're inside its capture range levels (16-252).
The other parameters are quite subjective and need to be evaluated on a calibrated monitor, looking for the skin for example. In addition, changing at capture level require tape-by-tape, scene-by-scene modifications, not really easy.

Just let the card capture what it wants, beeing sure that the lowest blacks are at 16 and the highest whites at 252 finding an appropriate scene as good candidate.

In post processing you can then modify what you want in a more effective way.

Put the sharpness of ATI USB 600 at 0, otherwise you'll have ugly halos.

Enjoy your captures!

[theseeker2]

Thank you all again for chiming in, I really appreciate it! I'm definitely doing all captures with sharpness of 0 with the ATI USB 600, thanks for the reminder on that.

It seems that having the brightness set on 100 on the card procamp, which is lower than the default, and leaving the contrast at the default of 32, ends up giving the best looking histogram on just about every tape I try to capture. The default 128 brightness seems way too bright on everything and leads to the whites on the right of the histogram being out of range.

I will try to upload some video samples here shortly.

[Skiller]

@Skiller, @lollo, @Sharc, any opinions on the two images above?

My opinion is, this cannot properly be judged with two still images, let alone on a display that is not a TV or video monitor.

I would capture with safe contrast and brightness settings which do add any additional clipping (see lollo's post), then use histograms to make corrections while also judging visually on a video monitor.

[theseeker2]

Today I played around with the sharpness settings on the ATI 600 USB in the VirtualDub procamp. There are lots of threads out there suggesting setting the sharpness to 0 instead of using the default of 2. I tried it both ways, and to my eyes sharpness of 2 brings out more details. For example, look at the difference in the detail in the left eye between these two captures. Everything is exactly the same capture-wise except for the sharpness setting of 0 in the first and 2 in the second.

Is this just my mind playing tricks on me? Do these additional details not actually exist in the source? This is a commercial VHS tape btw.


[Attachment 73437 - Click to enlarge]


[Attachment 73438 - Click to enlarge]

https://imgsli.com/MjAxMDE3

[lollo]

We can do the same or better in post-processing, whitout introducing halos (hopefully).

If you deeply check your captures with sharpness=2, you'll probably find portions with evident halo artifacts.

[Skiller]

Is this just my mind playing tricks on me?

Yes, it is. There is zero real additional detail in the sharpness=2 capture. Actually, it is worse – the noise is sharpened and halos are introduced.

[lordsmurf]

There's really not a huge different between the pair.
- Enhanced grain, slight contrast boost.
- Not much ringing/halos in either.

I hate the term "clipping" when applied to capture cards, as it gives a false impression that the card has done something wrong. On the contrary, the capture card is capturing legal values. The illegal values are made legal, the so-called "clipping" or "crushing". Proper video workflow is to adjust the video values prior to capture, usually proc amp. Illegal values get crushed/clipped to legal somewhere, eventually. Thus is the nature of colorspaces.

[theseeker2]

Thanks all, really appreciate the feedback. I will stick with sharpness=0 for capture.

Any recommendations for tools/plugins to add just a little bit of sharpness in post? My ultimate goal with this footage is to upload to YouTube in case that helps, and ffmpeg is a big part of my post processing.

[lollo]

Any recommendations for tools/plugins to add just a little bit of sharpness in post?

AviSynth, LSFmod, CAS, SeeSaw, many others available: http://avisynth.nl/index.php/Category:Sharpeners