bad quality with virtual dub - black horizontal lines/blobs

[_N_]

I've spent quite a while trying to get this sorted.

Firstly, I record stuff with a VCR and then I record it onto my PC via my TV tuner. I'm using windows XP Pro Sp1.
I've been doing this for quite a while, but recently the video's come out looking really poorly.

Can someone explain to me, why is, that the preview window in VirtualDub looks really nice, while the actual captured file is really bad quality.

It happens on all video's. It didn't use to.
I chose this particular video because it has a lot of black next to white parts and then the black spills over into the rest.

I've played around with deinterlacing etc, read the guides etc,

but, why is the preview ok and the captured file looks like crap?

Here are the screenshots:
http://onlygod.orcon.net.nz/tuner.jpg

http://onlygod.orcon.net.nz/tuner.jpg

[fccHandler]

What kind of capture card do you have? Your picture looks exactly like some of the captures I have been getting with my ATI All-In-Wonder 9600, and I also use WinXP Pro SP1. I still don't know the actual reason for it, but I suspect it's losing h/v sync because of weak signal, or its pesky "Macrovision detection" kicking in erroneously.

I had the opportunity to test a time base corrector (TBC) device, and in my case the problem cleared up completely. But TBC's ain't cheap, and right now I can't afford to purchase my own. I may have a better solution, though. Last week I happened to find the ATI TV Wonder VE on sale for $30 USD, and I grabbed one. This card uses a BT878 chip, and so far it doesn't seem to suffer from the same video scrambling problem my expensive AIW has. Go figure... :rolleyes:

[_N_]

My tv tuner uses a BT878 chip.
Any way of getting around this problem?

Howcome the preview in VirtualDub is such good quality?

[Arachnotron]

Could you give us the settings you use in vdub? And which driver do you use, the one that came with the card or BTWincap? What codec do you use?

Firstly, I record stuff with a VCR and then I record it onto my PC via my TV tuner. I'm using windows XP Pro Sp1.

That is not really a good way to do it.
In order of decreasing quality:
1.record directly on the PC using the on-card tuner
2.record to VCR first, and through composite video to PC afterwards
3.record to VCR first, and through rf / tuner to PC afterwards

[_N_]

ok, I use the drivers that came with the card, I tried using BTWincap but then it wouldn't work. The card is called "TV excel". TV tuner/FM radio/remote/RCA in, etc..

settings in Vdub,
since I only have the original drivers, I capture at 320x240.
no compression, I got a large 10GB NTFS partition, so it's not a problem.

I can't record directly with TV tuner, cause I'm mainly trying to copy old home video's or the stuff I record on tape.

So, I got an RCA cable between VCR video out and tuner card in. For audio, I got RCA to line in on sound card.

If try recording in other software, I also get those black lines, so I wouldn't blame Vdub for the poor quality, but this is the thing, in the preview window, in VDub, it comes out really nice.

[Arachnotron]

I thought New Zealand uses PAL ? Those are NTSC settings.

Try capping with VirtualVCR
set resolution to 696x576
25 frames per second
color space yuy2
compression huffyuv

And see what happens.
[edit]maybe even better: no compression at all. The resulting file would be huge, but you only need a few seconds to test. And disable the preview during capping.

Since vdub can have problems with certain drivers, for troubleshooting it is best to start with a directshow app like VirtualVCR. Once you have that running, you can tackle vdub.

[_N_]

Ok,
I've done what you said,
this is what the capture looks like at full res

http://onlygod.orcon.net.nz/original.jpg

and then,
I deinterlaced it (blend both fields)
sharpen
resize to 320x240 - precise bilinear

and this is what I get, better quality than before

http://onlygod.orcon.net.nz/final.jpg

that's been quite helpful,

but, I'm still wondering, how can virtual dub get such nice quality in preview window?

also, can you recommend any filters which might be better than what I used? as you can see, I still get those black lines at the end.

[Arachnotron]

also, can you recommend any filters which might be better than what I used? as you can see, I still get those black lines at the end. Those black lines/distortion in lines at the bottom is perfectly normal for VCR.

I must say I'm puzzled by your first pic. The distortions look like a poor VCR/ poor tape, but that should affect the preview too. The preview is from the tape by the way, not from the original broadcast through the card tuner?

You could try capping at 348x288 (and padding to 352x288 afterwards). It would cause the card to discard a field each frame, so the distortions would not show up as much as they do with deinterlacing.

[_N_]

>>The preview is from the tape by the way, not from the original broadcast through the card tuner?

Yes, it's from the same tape.

I went out and bought a brand new tape to make sure that it's not the tape causing the problems.