Capturing vhs - not happy with quality

[drcldrcl]

I'm using a PANASONIC FS200 PAL with a KWORLD DVBT210SE capture card (Philips SAA713x) connected vis s-video.

I'm trying to capture as cleanly as possible. I dont seem to have a problem with mass chroma noise but i seem to be getting a what i can only describe kind of crosstalk/ dot crawl pattern which is most obviously visible where a strong colour is adjacent to black. I thought S-video did not have this issue.

It's not even visible to the naked eye when uncompressed but i want to be able to create the highest quality mpeg2 interlaced encodes. You need to zoom in and playback at half speed to see it

I have uploaded a file to mediafire -its only a few seconds because it is huffyuv.

http://download98.mediafire.com/2icp...zs2ns5/CAP.avi (44MB)

Any advice on how to cure this would be greatly appreciated.

Duncan

[TheSkiller]

Ah, the Panasonic NV-FS 200, I have that VCR too, it's excellent. Be sure to operate it in Edit mode by setting the switch on the very left of the control panel to the right position (called "EDIT - ON"). Note that the sharpness slider does not have any effect anymore then, you're getting the rawest video output possible.

I thought S-video did not have this issue.

Indeed, it doesn't. However, if the video signal was a Composite video signal at some point before it was recorded to (S-)VHS with an S-VHS unit using it's S-Video input (!), it had to be Y/C separated at some point (maybe by the recording VCR). It's possible that this has happened with a simple technique (like the color-trap one), introducing dot crawl and rainbowing. And that is why there can be some slight dot crawl in a (S-)VHS recording that is played back via S-Video.

I think there is some very faint remaining dot crawl in your video, however it really is VERY faint. Your capture looks pretty clean, not much to do imo.


But, are you sure 704 is the correct width for your capture device? With the old WDM 1.4 Terratec drivers for SAA7134 it was correct, but I know for a fact that the analog capture window of the new BDA drivers is 53.333µs which equals 720 pixels. That and the size of the black borders on the left and right makes me pretty certain the correct capture width for you is 720. Also keep in mind that the picture is shifted upwards by 2 lines when capturing PAL with SAA7134. Don't ask me why, but the drivers (any) don't get that right.

Edit: Saturation seems to be a bit too strong, it's actually exceeding the TV-levels range on the U-plane.

[drcldrcl]

Well I'm not too concerned about exact aspect ratios unless it affects the picture quality when it comes to encoding. I chose 704 simply because I can use horizontalreduceby2() later if I wish. Obviously the black borders are detrimental and eat up bitrate though.

I'm just using the standard drivers from the kworld site. I didn't know teradec had anything to do with it. Apparently Trident own the chip rights now.

Well i suspected it had something to do with a composite signal somewhere but I haven't tested any other tapes yet. I will try to find a CG scene or overlay on other tapes.

My concern is that the encoder chip itself is not receiving the signal as separated (not sure why kworld would do that)

The other possibility is that my VCR is faulty.

[TheSkiller]

Originally Posted by drcldrcl

Well I'm not too concerned about exact aspect ratios unless it affects the picture quality when it comes to encoding.

But isn't the aspect ratio also part of "picture quality"?

Originally Posted by drcldrcl

Obviously the black borders are detrimental and eat up bitrate though.

Since the edges are soft (at least the ones of the left/right borders) it doesn't really eat bitrate, especially if you're doing a high bitrate MPEG2 encoding it really doesn't matter.

Originally Posted by drcldrcl

I'm just using the standard drivers from the kworld site.

Then it's probably a BDA driver for the SAA713x.

Originally Posted by drcldrcl

My concern is that the encoder chip itself is not receiving the signal as separated (not sure why kworld would do that)

That is unlikely because for that to work the capture card would need a circuit that can encode a composite signal and it would make absolutely no sense to even put that onto a capture card. All it can do is decode and digitize Y/C and Composite input.


Your VCR is not faulty, the picture looks just like VHS looks, maybe you're expecting too much. Your picture is very good looking - like I would expect it too look from this VCR and a tape in good condition. Are you using EDIT-mode?

[drcldrcl]

OK so I did a few experiments.

played with the composite input to see if the comb filter would remove the problem. no change.

Turns out when i play the tape back at the slowest rate using the VCR jog control with the capture card contrast and saturation to max, I can see the interference pattern in slow motion. That would make me believe its on the tape. It appears to be like diagonal RF pattern like you get if your TV isn't tuned in properly.

Thanks for the input.

[mike20021969]

Originally Posted by TheSkiller

Are you using EDIT-mode?

If he tells you, he might have to kill you afterwards

[TheSkiller]

Huh? Sorry I don't get it. Since he never responded to that question I assumed he has not yet cared about that setting at all.

[drcldrcl]

i realise there is an edit switch which does make the output look great to the eye but i find that it produces more noise which is creating artifacts when i encode to dvd even with with CCE at 9mbit. im trying to eliminate noise at much as possible. I feel like the player is adding noise.

I am forced into capturing with the sharpnesss setting towards soft and my capture card sharpness on a negative.

[Mounir]

Originally Posted by drcldrcl

OK so I did a few experiments.

played with the composite input to see if the comb filter would remove the problem. no change.

Turns out when i play the tape back at the slowest rate using the VCR jog control with the capture card contrast and saturation to max, I can see the interference pattern in slow motion. That would make me believe its on the tape. It appears to be like diagonal RF pattern like you get if your TV isn't tuned in properly.

Thanks for the input.

Buy a better cable (shielded preferably to avoid RF and EMI) but it's possible the tape was recorded with these lines.
Also setting brightness/contrast is essential in my experience try to raise up the brightness somewhere between 10-20 units and see if that helps

[drcldrcl]

the cable is very short and very expensive and is a very sheilded and even has coring. its not the cable. I believe it is the tape but the player does seem to add noise too - it oversharpens in my opinion.

Anyone know what the best type of head cleaner to use in this player?

thanks

[TheSkiller]

Originally Posted by drcldrcl

Anyone know what the best type of head cleaner to use in this player?

Isopropyl alcohol (99%) and some strips of plain white print paper (uncoated!) are the best way to clean the heads and all the other parts that come in contact with the tape (for those parts you can also use Q-tips, but keep them away from the head drum). You can get Isopropyl alcohol in a pharmacy store (very cheap btw), but be careful not to buy the more common mixture with 30% water, you need 99% alcohol!
I've done this myself several times, also with the NV-FS 200, works like a charm and surely better than a cleaning tape and it's also very gentle to the heads (well, if you're careful). In fact, when I got my NV-FS 200 the head drum was so dirty you could see the dirt with the bare eye easily - now it's all shiny and clean and the picture quality is awesome.

Here is a tutorial about how to do this, it's in German but there are also some pictures to give you an idea.

[Ghitulescu]

I never used any fluid, only plain copymachine paper or cotton hard tissue (no loose fibres as they can clog the gaps).

[Oleg Rode]

Isopropyl alcohol (99%) and some strips of plain white print paper (uncoated!) are the best way to clean the heads and all the other parts that come in contact with the tape (for those parts you can also use Q-tips, but keep them away from the head drum).

It is better to use acetone, (NOT the nail polish remover). And yes, use little bits of paper to prevent video heads cracks

[Ghitulescu]

Originally Posted by Oleg Rode

It is better to use acetone, (NOT the nail polish remover).

I'm not that sure ....