Pixellated horizontal bands

[Macon]

Hi,

I've got a good quality PAL VHS recording of a digital TV broadcast, which I want to convert to DVD. I'm using the Hauppauge WinTV PVR USB, which can't capture as AVI, but as MPEG2 (full D1 6Mb/sec VBR). The audio went out of sync in the MPEG, but I was able to fix that up using ProjectX, which left me with separate MPV and MPA streams.

I didn't do any more processing on these streams - just imported them straight into Ulead DVD Workshop 2. Workshop didn't attempt to re-encode the MPV file: it was happy to leave it as it was. I created an ISO, which I mounted using Daemon Tools. When I play that on my PC, everything looks fine - but I've now burned a whole string of coasters attempting to turn this ISO into a DVD (after first defragging my hard drive, and closing all other applications)....

The problem is that I end up with this weird artefact at the bottom of the TV picture. It's a flickering horizontal band of pixels going all the way across the screen (usually about 6 lines in height, but sometimes more). A lot of the time, there is a similar artefact at the top, and they extend too far for me to be happy to just crop the picture. They continue throughout the entire recording, independent of how much motion there is on screen. The rest of the picture looks super sharp and clear.

Now, there was no sign of this on the original VHS recording, or when I viewed the ISO on my PC. I thought this might be because more of the picture shows on the TV, but no - I checked, and the ISO version doesn't appear to be a clipped version of the DVD version.

Any ideas on what causes this interference, and a painless way to make it vanish? If I let DVD Workshop recode at a lower bitrate, the pixellation does seem to lessen, at the expense of a generally more blocky picture - but why should that be the case? 6Mb/sec VBR shouldn't present any problem for a standalone DVD player, should it?

I suppose the obvious answer is that its a problem with the media I'm using (jewel-case Maxwell DVD-Rs), and if you reckon that's the only possible diagnosis, I'll go out and experiment with some other brands. However, these have worked beautifully for me in the past when using material ripped from DVD rather than tape. (I did make one token attempt with another disc I had lying around, and experienced the same problem, but it was a lousy brand anyway).

I've got all of the standard kit to put things right, if necessary, but nothing I've attempted has worked so far (recoding in TMPGEnc, spatialsmoothen in AviSynth 2.5), and I've been mucking about with this project since Easter now....

Thanks,

Macon.

[rfmmars]

Its not clear to me if you have tried to record direct without the VCR from your digital source. Also can you make a DVD file on the hard drive instead of burning?

Is the noise on top of the video or are you seeing data lines in the vertical blanking that didn't show because of overscan of the TV?

richard
www.photorecall.net

[Macon]

Hi Richard,

No, my original recording is on VHS tape. When I first got the Hauppauge, I tried to configure it so that I could capture a digital signal on the fly, without first taping, but I couldn't persuade it to work (which isn't to say that it can't be done!).

I always create an ISO, and burn from that, to make sure the encoding worked properly. However, if I give up on burning, and just aim to watch the ISO on my PC, I'm going to run out on disk space sooner or later, so I'd prefer not to do this if possible.

As far as I can tell, the noise appears to be on top of the DVD recording. I don't think it's about overscan: when I play back the ISO, I can see a single pinky green line at the bottom, which I associate with VHS recording, and which I was expecting to see on my final DVD recording too. When I look at the DVD picture, the lines which are pixellated appear to be lines which displayed OK in the ISO, rather than extra lines which were never designed to be seen.

Thanks for your help,

Macon.

[rfmmars]

Macon.........I don't understand why you can't record in real time if you useing the pass though on the VCR, there should not any difference whether its live or Memorex.

However I remember a problem that I had with a satellite rig feeding a beta VCR with lines. You not see them monitoring the video out of the vcr, but on playback they were there.

The problem was with the vcr and only recording SAT.feeds.

In your case if you can't record direct from the Sar. receiver, and can't record live with the feed though from the vcr, then its looks like the problem is the video out of the SAT. receiver.

richard

[Macon]

Yeah, I'm sure you're right about real time recording - it must be possible. But I've never got it to work in practice (passing a digital TV signal through the VCR involves turning on another set-top box in the chain going to the Hauppauge, and it didn't like it).

However, it's too late for this particular project anyway, and I just have to work with the VHS recording I've got. I wasn't initially expecting fantastic quality, and was surprised when the ISO looked as clean as it did: I'm just perplexed that I can't turn that into an equally good looking DVD.

With your problematic satellite project, did you create an ISO first? And if so, did the lines show up on that, or did they only appear once you'd burnt to DVD?

(I'm also going to go back tonight and double-check your overscanning suggestion, just to make sure that this isn't it)

Macon.

[rfmmars]

No there was no iso file. The satelite was a 4 gig system way before the DVD.

Then your capture card has only RF in, not video in?

richard

[Macon]

RF in? Video in? Gulp - dunno. I have very little understanding of hardware...

However, you've just spurred me into making a (totally off-topic) discovery. My Hauppauge PVR is a USB device, not a card. When I tried and failed to pass a digital signal to it in the past, the route I was using was:-

(TV aerial) to (Digibox) to (VCR) to (Hauppauge), which let me view all my analogue channels via the VCR, but I got no reception on the digital ones.

I've just experimented, and if I remove the VCR from the chain - i.e. do (TV aerial) to (Digibox) to (Hauppauge), the digital channels DO come up.

So.... I'll never have to copy digital TV to VHS first as an initial task - I'll be able to capture direct, which is great - many thanks.

****************************

But meanwhile, I've still got this tape I want to turn into a DVD!

I've checked again, comparing identical frames of the ISO and DVD and it definitely isn't an overscanning issue.

One new thing which I noticed when stepping through frame by frame is that the interference isn't on every single frame: some are perfect. But it's on enough of them to make it look as if it's continuous when viewed.

I know I'm being repetitive, but I just feel that if the ISO is fine, it must be possible to squeeze a good DVD out of it somehow...

[rfmmars]

Glad you tripped on the recording solution, many times that's what happens.

Its still sounds that it may be data in those lines. Do you have more than one DVD burning program that you could try, or have you aready done that?

richard

[Macon]

Ooh, that's a good idea - I haven't tried that. I'll give Nero a go, and see if it does any better.

[rfmmars]

This may be important in your case

Some CD-burning applications create plain ISO 9660 images, .while others interpret the ISO format as they like . Nero, from Ahead Software, uses the NRG suffix to name its ISO images.

ISO images created by Easy CD Creator (from Roxio, Inc., which was spun off from Adaptec, Inc. in September, 2000) contain some lead-in and lead-out bytes around the core of the 2048-byte sector.

This explains why ISO images created by Easy CD Creator cannot be burnt by all burning packages (for example, CDRWin complains about the file not beeing a multiple of the sector size). On the other hand, Easy CD Creator can burn plain ISO images written by other packages.

richard

[Macon]

Hmmm... see exactly the same pixellation when burning with Nero: no better, no worse.

I've got a couple of other burning programs I could try, but I suspect it might be wasted effort.

Oh dear.