Best VHS capture resolution??

[ForYouAndI.com]

I know this is a question that has been asked alot because I have read alot about it. There are so many opinions that I don't know what to choose.

My understanding is that VHS signal comes in at ABOUT 352x480 NTSC. BUT some people recommend capturing at 720x480! What is the deal? If the signal comes in at 352 why up it to 720? Even this site:
http://www.digitalfaq.com/dvdguides/capture/intro.htm
suggests capturing at 352x480.

However, I did my own little test. I captured one at 352 and the other at 640 and the 640 seems to look better when burned to DVD with WinDVD Creator 2. I am not sure if it was the capture that made it look better or if WinDVD Creator 2 does a better job at sizing down than sizing up??

Another thing, I am using VirtualDub to capture and have I am not sure what the difference between Capture Pin and Set custom format is, because when I change the Capture Pin the custom format also changes with it.

Please help me understand these things.

[yoda313]

I captured one at 352 and the other at 640 and the 640 seems to look better when burned to DVD with WinDVD Creator 2

640 is not in the dvd specs. It would have been resized to 352 or more likely 720.

352, 704, and 720 are the main acceptable dvd specs.

halfd1 352x480 is probably more than acceptable for most cases. Its a matter of personal preference in my opinion.

[Barnabas]

352x480 is correct for non SVHS. 352x480 will capture all the rez that the tape has in it.

[ForYouAndI.com]

"640 is not in the dvd specs."

I knew that and is why I said this:

"I am not sure if it was the capture that made it look better or if WinDVD Creator 2 does a better job at sizing down than sizing up??"


"352x480 will capture all the rez that the tape has in it."

Than why did the 640x480 look better, you think?

[thecoalman]

"I am not sure if it was the capture that made it look better or if WinDVD Creator 2 does a better job at sizing down than sizing up??"

Any software will do a better job going down, resizing the resolution upwards should be avoided. Matter of fact if you capped at 620x480 and did a side by side comparison of one resized to to 720x480 and the other resized to 352x480 the one resized to 352x480 will look better. Give it a try............err I guess you already have.

BTW, I'm assuming your encoding and authoring your video 352x480?

As for your origianl question you'll get a lot of opinions on that. Persoanlly I capture at 720x480, I really have no choice because I use a ADVC. I leave it at 720x480 using a reasonable amount of bitrate usually 6000kbps.

Overkill? Probably, but I'm not concerned with disc space.

[junkmalle]

It varies with different capture cards. With my Hauppauge WinTV PVR-250 VHS caps at 720x480 are slightly clearer than 352x480.

[ForYouAndI.com]

"BTW, I'm assuming your encoding and authoring your video 352x480?"

That was my GUESS. Guessing is one of the things I hate about WinDVD Creator 2. The only info it gives me is 1 hour dvd, 2 hour dvd...I chose 2, hoping the resolution was 352x480.

[ForYouAndI.com]

352 capture bicubically resized to 640:


640 capture:

[davideck]

With my Hauppauge WinTV PVR-250 VHS caps at 720x480 are slightly clearer than 352x480.

That has been my experience as well..
I have also noticed the same thing with Beta.

[thecoalman]

The only info it gives me is 1 hour dvd, 2 hour dvd...I chose 2, hoping the resolution was 352x480.

Bitrate determines the length of video, the resolution has nothing to do with it. I'd imagine that product has the option somewhere to adjust the resolution. If not get a different product.

If it doesn't I'd guess it's probably resizing everthing you put into it to 720x480. If your capturing anything less than that the quality is going to suffer no matter what it is. If you use a lower resolution video you have to encode and/or author at that resolution.

[junkmalle]

Here is an old post of mine with samples captured at 352x480 and 720x480 with my PVR-250:

https://www.videohelp.com/forum/viewtopic.php?p=1336431#1336431

You can easily count the vertical bars in the lower two patterns in the 720x480 sample. You can't in the 352x480 sample, even if you enlarge the image.

[slacker]

WinDVD Creator was one of my first apps. 1 hour mode = 720x480. 2 hour mode = 352x480.

[thecoalman]

Bitrate determines the length of video, the resolution has nothing to do with it.

That should read: Bitrate determines the length of video you can get on one disc, the resolution has nothing to do with it.


Just thought I'd make that a little clearer as it wasn't entirely clear.

[ForYouAndI.com]

Which one of my captures would you say is better? They're both really bad aren't they?

junkmalle, those images weren't stretched at all, just cropped?

[junkmalle]

Which one of my captures would you say is better? They're both really bad aren't they?

The 640x480 capture looks clearer. But we don't know exactly what the source looked like.

junkmalle, those images weren't stretched at all, just cropped?

Yes, those were crops, not resized, and saved as lossless PNG for posting.

[winifreid]

You might be comparing apples and oranges. If you increase the bitrate for the 640 then it could look better. Also, if both examples were resized during authoring to 720, then the 640 would definately look better. But if you use the same bit rate and don't resize the 352, the 352 should look better. Or at the very least look the same and take less time to encode and less space on the disk.

[anitract]

Okay, a lot of people on these boards say that there is no point in going higher than 352x480, but I will tell you that capping at 704 or 720 WILL give you a sharper, more detailed picture (when viewed on a TV). At least this is what I found using ATI AIW. Do a comparison for yourself.

EDIT: Now whether or not the increase in detail is worth the increase in file size is debatable. I think it is.

[lordsmurf]

You cannot make screen caps to compare resolutions. Period.

Of course 352 will look worse on a computer monitor, you mess it up by stretching it out into a 1:1 space (and using a poor bicubic resize at that!) and totally destroy the 4:3 rectangle pixels.

[whitejremiah]

a lot of people will tell you that 352x240 is good enough for VHS.....i personally do NOT agree with that, you can see macroblocks that DONT appear in the original source file......personally, i'd just go with 720x480 and eat the extra space that it takes.....and dont try and shove 4 movies from VHS captures to a dvdr either.........ive seen people try and do that, not worth the quality loss in my opinion......do 1 movie per dvdr and set the bitrate as high as you can get away with...dvdr's are cheap enough these days anyhow.....good luck with your conversion process.

[winifreid]

I may be wrong, but doesn't macro blocking result form low bit rate, and not resolution?

[ForYouAndI.com]

"Of course 352 will look worse on a computer monitor, you mess it up by stretching it out into a 1:1 space (and using a poor bicubic resize at that!) and totally destroy the 4:3 rectangle pixels."

352 looked worse on my tv too. And what do you mean by poor bicubic resize? Bicubic is one of the highest quality stretches there is.

[slacker]

That should read: Bitrate determines the length of video you can get on one disc, the resolution has nothing to do with it.

Since your selected resolution DOES effect the ultimate bitrate you choose, it DOES effect the length of the video indirectly. What am I missing?

[Nelson37]

Boy, I get really, really tired of answering this question.

Is 352x480 the nearest approximation of VHS resolution? Yes

Would this, THEORETICALLY, be the best resolution to capture at? Yes

Do these two tidbits of information have anything at all to do with what will give you the best looking capture? NO

Capture cards almost all capture at a FIXED RESOLUTION. Whenever a resolution is requested that is different from this, the card will then apply a software resize to achieve this. Some cards will also apply a smoothing filter, the test I have seen proved conclusively that on at least one card, such a smoothing filter was automatically applied at any res UNDER 360. They had it down to the point of identifying the pin number on the main chip where this instruction was activated.

Note that it does not matter if you, I, or anyone else think this is a good design, makes sense, or we like it. These are the facts. Numerous cards and their fixed capture resolutions are listed at various sites, I have not seen ANY information on ANY card which has a truly variable capture resolution. Regardless, I know that MY card is fixed.

Find the native capture res for your card. Capture at that res. If it is already DVD-compliant, you are all done. If it is not, then you must test whether a real-time resize performed by the card is equal, superior, or close enough to a capture done at native res, then resized in software later. Note that cropping ability may, or may not, affect the actual captured resolution.

A note for all those with the charts and graphs. IMO, it is NOT POSSIBLE to prove that strawberries taste better than bananas (insert your own fruits here) and I for one have no interest in such an excercise.

I recommned you solve this issue the same way I, and others have. Test the capture both ways and look at the results. Dozens of test clips and 5-10 independent observers confirm for me that on the AIW 128 pro and the AIW 7500, 720x480 capture of VHS looks better than a 352x480 capture. It does not really matter WHY or HOW this occurs, does it? You are not testing different capture resolutions, you are testing different resizing methods and filtering.

I see you have tested a resize to 640. What would be the point of such a resize, if your goal is DVD playback? 352x240, 352x480, or 720x480. These are the available targets. Anything else is a pointless waste of time, unless PC playback is the goal.

[lordsmurf]

ATI AIW cards have a native size of about 704x480, and that is part of the reason why they do so well at 352x480.

Unlike crappier BT8x8 chipsets and others, which have any number of odd resolutions, and downsizing looks so bad. For those cards, either capture at the goofball native size, or just do the safe 720x480 resolution.

[ForYouAndI.com]

Nelson37, now everything makes sense. I don't trust my capture card. It is a eViewTV card by Encore. The manual says the chipset is Bt878/878a.

Do you think I could find out WITHOUT trial and error what resolution it captures at?

[junkmalle]

this might help:

http://btwincap.sourceforge.net/

[ForYouAndI.com]

How will that help me? I even downloaded the capture spy program and it did not even tell me at what resolution the card captures at.

[junkmalle]

How will that help me? I even downloaded the capture spy program and it did not even tell me at what resolution the card captures at.

I believe the BT848 chips capature internally at something like 1400 samples horizontally. So everything is downscaled from there. If you're capturing for DVD use 720, 704, or 352 pixels horizontally. Try all three and see which looks best to you.

From what I understand, the BTWinCap drivers are considered the best for capturing with BT8x8 cards. Try using them with the supplied capture software.

[Dasun]

In my experience, using a Datavideo analogue to DV converter, 720 X 576 VHS proves sharper than when I resize it to half D1. Hence I store my MPEG converted VHS at 720 X 576, with the highest bitrate I can get away with and I can not tell it from the original.

[ForYouAndI.com]

Nelson and junkmalle, are you both saying that my capture card probably captures at 1400 and then resizes it down no matter what I do? I'm asking this because VirtualDub never gives me the option of capturing at 1400.

Another thing that could be messing up my captures is which device I capture with. Should I use

WDM Image Capture (VFW)
or
Conexant's BtPCI Capture (DirectShow)?