Setup quality check, converting VHS tapes?

[Okiba]

Hi everyone,

I finally had some time yesterday to set up VirtualDub and try to capture a Demo. I followed sanlyn
guide, and I'm using VC500, along with an LG DVD/VHS combo unit (when we last talked, It wasn't clear if it had some sort of build-in TBC). The VHS is connected via Acoustic Research PR-121 Pro Series II S-Video Cable to the Capture device, and the machine is Windows 7.

My father brought me couple of random tapes from out collection. One is an old Cartoon. Which probably is not an amazing Demo, because the Cartoon itself is very old. The other video is a dancing competition. it's been taken non-professionally. I'm assuming lighting is a problem on the scene, but maybe it actually a good good.

if you can perhaps point me in the right direction, I can share a better types of demo. I did notice couple of things :

1. The final video is darker compared to what I can see being played on VirtualDB preview window. I'm not sure if that's a card problem, or I just need to play with white balance/contract to make it in the proper range.

2. I didn't notice any issue sync issue, but maybe it's because I took shorts demos, and I didn't lost enough frames along to way to notice it.

Thank you!

[traal]

Looking at the cartoon's histogram, the blacks are a little crushed. You need to increase brightness a little more when capturing.

I use VirtualDub's "gradation curves" filter in YUV mode to boost the luminance a little on the right and to adjust the ChromaB and ChromaR as necessary to fix color casts like I see in the cartoon (the whites are a little pink).

[Okiba]

Hello traal, thanks for the feedback :-)

Quote:

Looking at the cartoon's histogram, the blacks are a little crushed. You need to increase brightness a little more when capturing.

Is that specific specifically tied to the Capture device? or to the content? I'm assuming that I will have to do that Histogram check every time I capture a new type of content?

Quote:

I use VirtualDub's "gradation curves" filter in YUV mode to boost the luminance a little on the right and to adjust the ChromaB and ChromaR as necessary to fix color casts like I see in the cartoon (the whites are a little pink).

I never used filters before. I did find the "Gradation Curve" filter, and moved the line a little bit to the right as you suggested (maybe you can supply a picture just to make sure I did it correctly?) - and where can I find the ChromaB/R settings? Are those also settings that I can just leave like so for future captures because it's a capture device/VHS oriented? or again - it's to this specific cartoon content I shared?

Thank you!

[Sirworm]

Capture cards are known to do funky things with the video, changing the brightness being one of them. For an example, my VC500 made things brighter (at least on my Snow White retail tape). It could also be your video player application (meaning programs like VLC), depending on which one you use. There's a program called Crossbar Thing that, I believe, let's you change the values on the card itself... however I'd be careful when changing the brightness and whatnot on video, especially VHS tapes.

[hodgey]

You can adjust brightness, contrast, saturation and sharpness on the capture through virtualdub. Should be under video -> levels when in capture mode. You can use the histogram feature in the same menu. You will need to set video mode to "preview" (or "display with filters in virtualdub2) to get the histogram to work, can set it back to overlay afterwards, all this should be in the guide.

[traal]

Quote:

Originally Posted by Okiba

Is that specific specifically tied to the Capture device? or to the content?

Both! With my VC500 I go into VirtualDub's "Video -> Source" menu to find brightness and contrast.

Quote:

Originally Posted by Okiba

I did find the "Gradation Curve" filter, and moved the line a little bit to the right as you suggested (maybe you can supply a picture just to make sure I did it correctly?) - and where can I find the ChromaB/R settings?

Here's an example where I slightly increased luma (luminance) at the high (bright) end (see the little red square where I moved the curve). It also shows how to get to ChromaB and ChromaR:

gradation_curves.png

You should also use the R/G/B histograms in the "Color Tools" filter to check your work. It takes practice.

[Okiba]

Quote:

here's a program called Crossbar Thing that, I believe, let's you change the values on the card itself.

Yes, I don't think it's necessary. If you can modify those settings in VirtualDub, I'm fine :-)

Quote:

all this should be in the guide.

Is it. At least the simple stuff like Brightness as you mentioned. What traal mentioned seems to be more complex.

Quote:

You should also use the R/G/B histograms in the "Color Tools" filter to check your work. It takes practice.

Yes, I will give it a try at home and check Color tools.

So the only visible problem is the colour? Is it possible to know based on the Demo if the VHS has build-in TBC? and if not - how TBC will improve the current state?

Also, All the video I checked has those black and white distortion at the lower section of the video. I'm assuming it's common, because I see it in other captures online (not mine). What causing that? and should I bother about it? I'm assuming I can crop the lower section - but the guide advise against it during capture?

Thanks for the help guys!

[BarryTheCrab]

The distortion at the bottom of virtually any VHS capture is unavoidable and is called "head switching noise". Old timey tube TVs would zoom in on the video thereby pushing the edges off-screen so nobody ever noticed it. Masking and/or cropping is the common cure. I mask, it's easier. for me anyway.

[Okiba]

Quote:

Old timey tube TVs would zoom in on the video thereby pushing the edges off-screen so nobody ever noticed it. Masking and/or cropping is the common cure. I mask, it's easier. for me anyway.

Ohhh, that explains it :-)
Isn't cropping change the resolution and stretching the picture (and therefore hurting quality?) and what do you mean by 'masking'?

Thanks!

[lordsmurf]

Quote:

Originally Posted by Okiba

Isn't cropping change the resolution and stretching the picture (and therefore hurting quality?)

Yes, cropping is bad. Don't crop. Mask.

Quote:

and what do you mean by 'masking'?

Masking is just covering with black.
See this: http://www.digitalfaq.com/forum/vide...converted.html

[Okiba]

Thank you. I will check how to properly mask it.

Well - I didn't get any comments about quality rather than colour. I'm still not sure how TBC effect image quality besides helping to prevent frame-skipping and therefore audio sync issue. I also don't know if my VHS has TBC build in or not - but because there haven't been comment about it, I'm assuming it OK.

I will do three things next. One would be taking a longer video. To verify Audio doesn't go out of sync with longer captures. Secondly - I will learn how to adjust black-white levels with the Histogram, and colours with the Colour tool. And lastly, try the lower portion. I'm assuming there is no need for post filters - as non were mentioned.

I will re-post the final longer video here for another review. And if the comments will be positive, I will start migrating our 50+ family tapes one by one.

Thank you guys!

[msgohan]

The cartoon clip appears to be from one of those horrible compilation tapes. Not even gonna bother commenting on it.

Quoting hodgey from your previous thread:

Quote:

Originally Posted by hodgey

It depends, the digitizing process will strip away the non-visible parts of the image, which are what's used by e.g the TBC in SVHS VCRs to stabilize horizontal jitter. So what you get out is what the internal digitizer is capable doing with the original signal (which is significantly better than what the VC500 can do on it's own with a raw signal.) Though, the internal digitizer is not great at stabilizing horizontal jitter, compared to what a SVHS built-in TBC or a Panasonic DMR-ES10 DVD recorder is capable of correcting. You can see in the example video I posted the difference between the LG DVD recorder (should be similar to what your VCR will do) and the Panasonic DVD recorder (an ES10 would be at least as good.) on a tape that's in pretty good condition. The VCR part of the LG is a little better than the VCR I used though, but not as nice as a high-end JVC or Panasonic SVHS deck.

test.mp4 (dance competition) is a 714x576 MP4 file created by Handbrake: x264 (interlaced content incorrectly encoded in progressive mode) + for some reason, both AAC and AC3 audio tracks.

As hodgey predicted, there is uncorrected horizontal jitter that causes vertical lines to appear bent/wavy. There are also oversharpening halos, probably caused (mostly) by the playback VCR. It's tough to say much more with this wrongly-encoded sample.

[Okiba]

Quote:

It's tough to say much more with this wrongly-encoded sample.

Ha, that's a good feedback. I was following a guide how to use Handbrake externally, perhaps IT wasn't a good guide. I will check how to properly encode it with handbrake, probably someone has posted information about it here in the forum.

I wasn't able to identify those uncorrect horizontal jitter, I had the same problem with the original videos hodgey post. The LG RH video looks almost identical (if not better?) compared to the Panasonic EH57. Probably I'm not 100% know what to look at - and that's why I don't see it.

[hodgey]

To be fair the amount of horizontal jitter is not massive in either your or my samples of the LGs. You can see what the complete lack of correction looks like on my raw sample though. It's most noticeable when there's text or graphics that are supposed to be still. In my samples from the other thread it's most visible on the channel logo in the top right, though the recording is of decent quality so even the LG sample is quite stable (the raw capture is another beast.) On the cartoon sample you can see the image is bent a little to the left at the but the original film-to-tape is so unstable that it makes it hard to spot other issues, which is not uncommon on cartoon recordings.

You will have to see for yourself if you feel satisfied with what you get from your current deck.

[Okiba]

Now that you mentioned it, I did noticed it. But as you mentioned, it's one of the the things you need to look for to notice. I wasn't sure a combo of the LG VCR and the VC500 will work when I got it, the 2nd plan was to get a TBC. But I think it's pretty decent. Especially for non-trained eye. I think I'll start work with that. I also have a question about the compression, but I think it's goes beyond that topic and I'm assuming it's better not to mix. I'll open another one.

Thanks!

[josem84]

Quote:

Originally Posted by Okiba

Ohhh, that explains it :-)
Isn't cropping change the resolution and stretching the picture (and therefore hurting quality?) and what do you mean by 'masking'?

Thanks!

Cropping does not affect quality in any way… it just messes with the original aspect ratio, unless you crop the image using the right proportions. You want to crop and pad to do it properly.