VHS to DVD Conversion Question

[gratner]

I'm converting concert videos on VHS to DVD.

I'm using TMPGEnc to encode a 720x480 capture with 2-pass VBR and average bitrates of 6000 (overkill probably but I have the room) and using the noise filtering option.

It looks as good as the source in every aspect EXCEPT that when the background is very dark I notice some pixelation in the black areas.

What can I do to eliminate or reduce this pixelation on the black backgrounds?

Any help would be greatly appreciated.

Thanks.

[fmctm1sw]

Nice question, I've seen that in some of my SVCDs. I'd like that answer too....

[housepig]

you could run one of the Virtualdub filters on it to blur it slightly, that would help reduce the pixelation effect.

there was a great thread full of good links for info on cleaning up VHS - I'll dig up the link and post it here in a little while.

[housepig]

check here...

https://www.videohelp.com/forum/viewtopic.php?t=164765

[indolikaa]

A question, if you don't mind...

Have you tried CVD (also known as 1/2 D1) onto DVD?

[DJRumpy]

Your problem is probably due to luminance compression. A standard television can display only 219 luminance levels (16-235). A PC monitor on the other hand can display 256 (0-255). When you capture, be sure you capture in television format, and keep it that way throughout your entire conversion process. The problem could be introduced in either the capture, or the encoding process. If your using TMPGenc, try reversing the setting on the Quantize matrix tab: "Output YUV data as Basic YCBCr not CCIR601". Just to be sure though, see if your capture software has a setting for luminance range, and ensure it's set to 16-235, not 0-255.

All this means, is that any light, in the 236-255 range, and any dark area in the 0-15 range, will be compressed to fit into the 16-235 luminance range. When this happens, you get 'sparkles' in the dark areas (looks like faint blocks flashing on and off), and in the light areas, you get somewhat washed out brights. The dark areas will typically be most visible in black and dark green areas.

[pijetro]

To help alleviate some of your pixelization, perhaps try encoding Half D1 (352x480). This resolution should buy you some extra without sacrificing quality.
If it's quite bad, perhaps use AVIsynth or Vdub pre filtering (spatial soften). That will also free up much desired bitrate...
Is the pixelization on your monitor the same as what's representative on your TV set (I'm assuming that your final product is DVD)??

[indolikaa]

Have you tried CVD (also known as 1/2 D1) onto DVD?

To help alleviate some of your pixelization, perhaps try encoding Half D1 (352x480).

My thoughts exactly. That's why I asked if you had tried it. Capturing VHS at D1/6000 resolution is sheer overkill. In my previous experience, such overkill actually adds to problems that are common with VHS A/D transfers.

I had the same problem trying to transfer The Peacemaker from VHS to DVD. I used D1/5000 and the opening train scenes had horrible pixelation in the black fields. I tried CVD/2496 and the result was a bazillion times better. CVD is perfect for VHS, even at lower resolutions.

[DJRumpy]

My thoughts exactly. That's why I asked if you had tried it. Capturing VHS at D1/6000 resolution is sheer overkill. In my previous experience, such overkill actually adds to problems that are common with VHS A/D transfers.

Putting too much bitrate into an encoded mpeg will have no other affect than to increase the quality, to the point where the bitrate produces the image that is a 1:1 copy of the original. Any more than that is wasted. It will certainly not cause problems like the pixelation you described.

If your pixelation is due to bitrate, it would show up over your entire image, not just the dark areas. Your problem is due to luminance, if it shows up only in the dark areas. When you take the color black (luminance =0), and brighten it up to 16, to make it fit into the luminance profile for a telvision, it makes the black areas lighter, causing it to 'sparkle'. This will be evident with very slow or low motion scenes. If the black area is not all the same luminance (likely the case, as real life rarely is), then you end up with 'sparkles' in the dark areas that were brightened to fit the new luminance scale. Just think of it as turning the brightness up.

In either case, you will have to re-encode to fix the issue, whether it's luminance, or bitrate, so you should verify which it is. Find the scene where the pixelation is evident, and encode only that section. It should be a simple matter to determine which is the cause.

[indolikaa]

OK, DJ. Time to work your brain!

When I transfer VHS to optical media, I use a Sony SLV-R5U S-VHS VCR. I run that signal into the Dazzle DVC-II. From there, it's straight to optical media. Now, if I transfer and compare CVD 2496/256 versus D1 4992/256, there is less of this black pixelization problem in the CVD stream. Pixelization is not an issue on the VHS source material, as the signal is analog. But it suddenly becomes an issue during transfer. This would lead me to think the Dazzle is acting up.

I don't know if it is. Connect a satellite receiver or DVD player to the Dazzle and run the same test. There is no noticable black pixelization on either the CVD or D1 stream.

I read your reply and thought about it. It makes perfect sense. But I can't explain what's happening. I am still a certified Grade-A Newbie in this hobby, so any thoughts or enlightenment you might have is always welcome!

.indolikaa.

[DJRumpy]

Can you post a screenshot of a pixelated frame?

[indolikaa]

Yes, I can and will. Just as soon as I find the two discs in question...