710-USB software proc amp settings?
 

I am about to begin recapturing my Hi8 tapes using Sony TRV461E, with VirtualDub and the recently acquired 710-USB on a Win7 set up. I have a query on the capture device software proc amp settings.

Is this a one time process wherein I tune the 710-USB proc amp settings to avoid clipping for the brightest of whites and darkest of the blacks from my tapes? Thank you.

If it's a hardware device then it'll pass through so you can have another bite at the tapes, but yes that's one of the main functions of it.

I do have proc' amps but for myself, I prefer a solid capture then deal with it 'in post' with Premiere and calibrated monitors providing the video isn't too out of range, generally, they're not if they're from a reasonable source and not been copied a million times. If you can get it right in hardware, it's definitely a good option though.

Knowing where illegal values are is going to be a bit tricky without a vector-scope though, unless you capture and analyse your results by trial and error.

Hope that helps,
RR

In general the YUV levels depends on the video in the tape, but it is rare that UV are outside range 16-240. We always take into account luma only.

What is related to the card is its capture range, you can look at this post http://www.digitalfaq.com/forum/vide...html#post62640.
Out of range values "clipped" at capture stage cannot be recovered in post processing.

Finally, according to the capture range of your card, you could identify the worst segment in your video and tune the card proc-amp to stay inside the card capture range (i.e. 16-252) and use this setting for the whole tape. Difficult and tedious work.

Also consider that some user states that for some card, i.e. ATI USB 600, this procedure is not effective for "super blacks" Y<16. I cannot confirm.
https://forum.videohelp.com/threads/...ng#post2580749

Thanks RR & lollo2 for the responses.

Unfortunately I do not have access to a hardware proc-amp. I am planning to only tweak the brightness & contrast settings to get luma within 16-235 range for the extreme bright and dark sections. I am not planning to touch any of the other settings.

These are home videos on Hi8 tapes. With the default software proc-amp settings for 710-USB, I could see the histograms regularly hitting the walls at both ends.

It is good to know that I will have arrive at these settings only once for this card and that will work for all tapes. I will continue to monitor the histogram though.

This question is asked from the wrong stance. It infers that the capture card is doing something wrong, and harming the video. But that's not accurate.

Anything out 16 and 235 are illegal values for NTSC. Most capture cards therefore only capture the 16-235 legal range.

If your tapes are being "clipped", it's because the tapes have the problem, not the capture card. This is addressed with an external proc amp prior to the capture card.

The capture card's "proc amp" isn't actually a proc amp whatsoever. It corrects alreadty-digital values, and is not any different from post-capture NLEs for color correction. (I"m not 100% sure about every single card doing this, as it doesn't have to be this way, but I've yet to see one does any differently.)

Even if you capture the blacker-than-black and whiter-than-white levels, you still must correct those in post. It's not NTSC, and formats like DVD-Video will truncate them. Even playing a streaming version will be truncated to 16-235 by the television. The only "safe" place to view these badly-made videos is the computer.

The ATI AIW is one of the few cards that capture the entire range. (sanlyn used to harp on this topic quite a bit, and showed his VC500 to properly get the illegal values. However, my VC500 did not, as it's a variable card.)

I sometimes think too much is made of this issue. It mostly becomes important when you get into more nth gen materials, where even the slightest loss is magnified. Or if your video is fully overexposed or underexposed. For general home movies, you're unlikely to see major difference when watching for enjoyment. In most cases, it's the difference between seeing a head of brown hair, and the individual hairs, when pausing the screen and looking for flaws. Or fine details in clouds. This error rarely "jumps out at you" like wiggle lack-of-TBC errors, bad capture cards, etc. Your TV set and computer monitor likely monkeys with contrast values far more than anything the capture card does.

See also: DO NOT "correct" with a non-calibrated monitor. Because then you're just ruining video to look good on a single monitor.

PAL values differ, "clipping" less of a problem.

Thank you for the detailed explanation LS. I am trying to follow the "Capturing with VirtualDub guide" i.e. adjusting brightness and contrast in conjunction with the capture Histogram and Cropping features to set valid input levels for 16-235 video.

If the card's proc-amp corrects already digitized values then this exercise is futile. Histogram shows no overflow beyond the red bars; so I assume that USB-710 does not capture the blacker-than-black and whiter-than-white levels. Please confirm my understanding.

And these are PAL Hi8 tapes. When you say PAL values differ, do you mean the 16-235 legal range? Thanks.

Update on 710-USB proc amp settings.

I am attaching select segments from 2 VirtualDub captures - (i) with default s/w driver proc amp settings and (ii) settings tuned using histogram to keep luma within legal limits.
Attachment 14157 & Attachment 14158

Also attaching a few frames for side-by-side comparison with histogram scaled using - left image is from tuned proc amp and the right image is from default settings after cropping out blank edges and head-switching bands.
Attachment 14159 Attachment 14160 Attachment 14161

It appears that the 710-USB's proc amp corrects the video signal before digitizing - captures with tuned proc amp settings brings out details otherwise lost in extreme bright and dark areas.

Excellent!

You obtained this: https://imgsli.com/NzE4NjU

Edit:
You can also experiment that the missing details cannot be recovered in the capture without the procamp tuning even if you reduce the brightness (using for example Tweak(bright=-60, coring=false, dither=true)