Resolution size?

[akeller87]

i have a question or two that you guys will hopefully be able to answer. id like to get more into converting my vhs tapes to dvd, and ive tried a few, but the picture is fuzzy and blotchy when i watch it on dvd. would this be becasue i have the wrong resolution size? someone told me that tv's resolution is usually 352 x 480. so is that the resolution i should be capturing video in? or is that just a myth. i thought the higher the resolution, the clearer the picture. id appricate some clarification there.

also, what should be the data rate when capturing 1.) TV from my All in Wonder card. and 2.) from vhs? Pinnacle studio 8, which came with my video card has the high quality (dvd) settings as: 720 x 480 resolution and 6000 kb/s data rate. so what should i be capturing these two things at?

thanks

[akeller87]

anyone?

[hexxisoft]

capture as high as you want, and then downsize for DVD/VCD.

[dphirschler]

I would say that a typical TV is 640x480, but some better ones show more detail. I would capture and encode at 704x480 or 720x480 if possible.


Darryl

[overloaded_ide]

Where did you two guys pull those answers from?? And it doesn't matter the TV display, it's the source you go by. And why capture HIGH and DOWNSIZE, why not do it right the first time??

but the picture is fuzzy and blotchy

Capture at 352x480 and 6,000 bits per second! That will be as clear as your source for TV or VHS unless you have other problems like bad cable connections. As for fuzzy or blockyness ect.. that would most likely be to low a bit rate causing it not resolution. What rate did you capture at?
You are using Mpeg 2 also I assume.

Either other settings are wrong or external problems if that setting does not work well. Does the video look good on the PC full screen as you capture it? If so then it should look good on the TV latter with those settings. If it does not look good durring capture you have some other problem, because capture settings do not effect the display durring capture.

I never use anything over 352X480 and everything I do looks as good as the source VHS unless I push the bits per second way low to fit alot of time on a disk, carring more about the time on disk than quality. I rarely do that though.

You cannot tell the difference between the Love BUG VHS tapes and my DVDs! All 3 disks look as good as the 3 movies, all captured at 352x480 same as everything else on VHS has been. Normal TV broadcasts are the same thing.

[overloaded_ide]

Pinnacle studio 8, which came with my video card has the high quality (dvd) settings as: 720 x 480 resolution and 6000 kb/s data rate

Oh yes, and I forgot to mention, your not capturing a DVD as your source are you :P

And I am surprised they don't have that set for 8,000 instead of 6,000 anyway.

You might want that setting if your source is from a DV camcorder and professional quality as that would be a DVD quality source (maybe), but TV or VHS is not.

[akeller87]

thanks for the responses. as reccommened by overloaded_ide, ill try capturing at 352x 480 and 6,000 kb/s.

Oh yes, and I forgot to mention, your not capturing a DVD as your source are you

no, that setting was if you planned on putting your video on DVD. im sticking to my vhs tapes

[iantri]

Depending on the quality of the capture card, I would argue that it is best to capture at the absolute highest resolution possible, since capturing is an analog to digital process that can only decrease picture quality.

Certainly, if it is a short video (under 2 hours) capture at 720x480, as long as you are able to keep the bitrate high (over 5mbit).

[akeller87]

now i just have one problem guys.. my file sizes are too big. for 1 minute of video, the file size is 45mb. how do i get this down to somethign managable? i mean id like to be able to fit at least 1.5 hours of quality video on a DVD. is that possible or am i gonna have to lose quality?

[overloaded_ide]

Depending on the quality of the capture card, I would argue that it is best to capture at the absolute highest resolution possible, since capturing is an analog to digital process that can only decrease picture quality..

Totally wrong!
If you add info that is not allready present what makes you think you are adding any quality? Taking a 352 line image and turning it into a 720 line image does nothing to encrease the info in the image itself, what you started with. You are just filling in lines that don't exist!

And you got that backwards, capturing analog to digital process does not Decrease Quality! It does not increase either. It should be the same.
Going from digital to Analog Decreases quality!
Analog is the low quality source you are trying to covert to a high quality output (DVD) Why would it decrease?
Of course taking high quality DVD down to analog tapes will decrease the quality, if your DVD was a comercail DVD quality DVD.
But it does not even decrease quality if you are using a DVD you made from a VHS capture, since you never had better than the original VHS anyway. Yes I know, I have done this! Sometimes after authoring a DVD for a group I need to make tapes also for people that don't have DVD players. I play back the DVD and record to tape, they still get the same finished movie as everyone else. It's ALL VHS quality, because.... yes the source was VHS!!

Certainly, if it is a short video (under 2 hours) capture at 720x480, as long as you are able to keep the bitrate high (over 5mbit)

Again Why? Not to explain the same thing over, lets just say there is no reason to do things differently just because the Video is shorter. If anything increase the bitrate NOT the resolution! Your 720 5mbit setting for VHS will look like crap or at least NO better than a 352 at 5mbit, the higher the resolution the more Mbits needed to maintian equal quality, simple as that! Either they look the same, or 352 will look far better at the same bitrates. Less resolution, less info, less bits needed to store info to maintain equal quality. So again, use the setting closet to your source, not over!
As for bit rates, you can use about any bit rate that gives you decent quality you are happy with. Bitrate has far more to do with quality than resolution! To low bits and it look like crap, too high does not hurt anything, it just wastes space and shortens the time you can fit on a disk.
If you don't need the space or extra time then go ahead and use 8,000 if you want. May not be any better than 6,000 or 7,000 but so what. You are not adding extra info, your just adding extra bits to better store the info that is present to begin with.

[lordsmurf]

Depending on the quality of the capture card, I would argue that it is best to capture at the absolute highest resolution possible, since capturing is an analog to digital process that can only decrease picture quality.

I would actually have to agree with this. Some cards cannot resize very well. BT8x8 chipsets are a perfect example.

If you know your card is good (like an ATI or Hauppauge), then capture any resolution allowed.

[overloaded_ide]

now i just have one problem guys.. my file sizes are too big. for 1 minute of video, the file size is 45mb. how do i get this down to somethign managable? i mean id like to be able to fit at least 1.5 hours of quality video on a DVD. is that possible or am i gonna have to lose quality?

Ok, do quick math here. 1.5 hours is 90 minutes. 90 X 45mb=4050mb.
How many MB on a 4.7gig DVD R? About 4.3 actual gigs, and a real gig is more than 1,000 MB!
4050/1,000= 4.05 gig as the disk makers would figure it, and that's less than both a 4.7gig disk as they call it, or 4.3gigs it really is.
So it looks like you may fit 90 minutes at that rate with a little room to spare.
To be sure, maybe drop your bit rate by about 50?

I took the easy way out on the math, maybe someone else would like to use exact true figures to check how much room is actually left.
And that's figuring you were exact on the one minute time, and 45MB size. Alittle off on those 2 figures and in 90 minutes you could have larger or smaller than expected file sizes.

If you look around the site or do some searches, it should be easy to find exact numbers. Like 1024mb or something like that being a real gig, and maybe 4.35 gigs to a DVD R. At this time I just didn't care to look it up exactly to the MB per disk myself.

One of the problems with having too many computers, I am often not at the one I have something stored on. Or the software installed to look at my exact settings. Especaily since I will not connect my main systems to the net EVER, so I am not ever on those when in a forum!
Right now I am not home so I can't even access my network!

[overloaded_ide]

Depending on the quality of the capture card, I would argue that it is best to capture at the absolute highest resolution possible, since capturing is an analog to digital process that can only decrease picture quality.

I would actually have to agree with this. Some cards cannot resize very well. BT8x8 chipsets are a perfect example.

If you know your card is good (like an ATI or Hauppauge), then capture any resolution allowed.

I thought you'd be one of the many people to agree with me on this one. Don't you basically say the samething on yoursite?? VHS /TV is 352x480, and going higher does nothing but add un-needed dots/pixels which end up requiring MORE bits to store the fake added dots and pixels at an equal to source quality!

And if I am correct, in this case akeller87 has stated in the first post he is using an ATI card.

And in the USA aren't 352 and 720 about the only DVD valid resolutions, or have I forgotten some? Since 352 has been working for me for all my VHS captures I don't use the others very often. DV Camcorders I tried at 720, but I don't do many of those. And VHS looks the same as the master tapes in 352, even when doing a brand new first time played comercail VHS tape. Like Pirates of the Caribean, 352x480 = VHS quality DVD R from the VHS tape I used! And there seems to be very little difference in the one I made and the comercail DVD I bought also as far as video quality.

I am using a Video clarifier, though I have not yet bought a TBC. I run an RCA jack into that, and S-video out to the ATI AIW. I run everything though that device, even camcorder VHS tapes.

As you know from some of my older posts, I am always interested in trying new things, keeps it interesting. Like that wierd Titanic 2 tape set experiment I did with Tmpgenc DVD Author and DVD shrink along time ago, just to see what would happen.

[lordsmurf]

overloaded_ide, in general that's correct, but if you go through .. very carefully... on the site in many places, I put the qualifier of "good card, good software" an similar things.

I don't really consider cheapo BT cards as good cards. They do not scale well internally.

If you card is good, then yes, capture whatever you want. 720 will definitely be huge overkill for VHS. 352x480 is your best res, but only if the card cooperates.

Compare a BT8x8 352x480 PowerVCRII MPEG capture to a BT8x8 PowerVCRII 720x480 capture. Because both the software and hardware are not that great for scaling, you'll see this huge distance in quality.

In situations like this, I say to grab 720x480 or 640x480 AVI (unless you know the EXACT optimal res, and want to play with crop/clipping/etc), and then re-encode a final MPEG to 352x480.

So, yes, you read it right ... and we agree ... but unfortunately, some cards out there and some software can make the statements untrue. So it's got to be qualified.

Make more sense?

You and I are both operating ATI AIW cards. For the most part, we can do whatever we want, and it'll look to notch. It's good hardware, and ATI MMC is great software.

[DereX888]

lordsmurf, as much as I usually agree with you (and I agree this time as well), but I think youve really made a lobotomy to akeller87 with your last post



@akeller87:

Dont listen to these two PROs above discussing something you probably dont even know what the f***k theyre talkin about

Since you have All-In-Wonder (I assume it is any of the AIW Radeon series, not older) then just create new capture profile in your MMC and set it as follow: size 352x480, format MPEG-2 (for DVD), bitrate VBR max=6Mbps, target=5Mbps, audio MPEg-1 Layer II, 48000Hz, 224kbps.
VideoSoap and other options are totally up to you, but dont use too much filtering with VideoSoap if you dont have powerful CPU (2-2.5GHz +).

have fun.

[lordsmurf]

Oops. Yeah, I sort of glossed over the original question and jumped into something related.

Yes, 352x480 at 4.0 MB/s for the ATI AIW card in question is perfect for almost all sources (especially VHS), and 720x480 is really not needed.

The only time I use VideoSoap is a custom-adjusted 17% despeckle filter for EP tape grain.

Do this:
http://www.digitalfaq.com/capture/atimpeg/atimpeg.htm

[SatStorm]

IMO, with NTSC sources, capture the higher you can, adjust / filter / resize and encode.
With PAL sources, it is more of a card thing. BT8xx cards (Older Hauppauge included) need to capture the higher you can (768 x 576) and resize to whatever you wish for best results. Cards like the nvidia ones, don't really care about it.

I believe that the cards that natively capture at 704 x 576 / 480, don't have a real problem to capture at 352 x 576 / 480 direct. Those cards are the ATI ones, the nvidia ones and probably those based on the philips chipset.
Cards that captures at 720 x 576 natively, are not the best to capture at other framesizes.
BT8xxx cards is a complicated thing, mainly because of the btwincap drivers that push them at their limits! General speaking, it seems that the higher they can capture is 688 x 480 for NTSC and 696 x 576 for PAL. Then, you add the lines you need to end up to 704 x 576 (add black boarders that is). The other alternative is to capture 768 x 576 and resize manually yourself (with correcting the aspect ratio at the same time).

Finally, if you use mainconcept to capture realtime to mpeg 2 with any card, you have to capture at 720 x 480 / 576 (or higher), because of a bug this encoder has. If you capture lower (not encode lower, those 2 settings are totally different....) then you might have some field distortion (like statering...) at the bottom of your screen.

[iantri]

I think you might be mixing up two seperate issues; that is the case with certain BT8x8 card card drivers, however with the btwincap drivers all of them should produce a proper image at 712x480. (Pad/crop as desired).

[DivXExpert]

You will see higher quality if you capture at a higher resolution. Try Printing something on a laser printer at 72dpi, then scan it at 72dpi, and scan it at 300dpi. Even though the printed material was only 72dpi to begin with, the 300dpi scan looks better. Resize the 300dpi scan down to 72dpi, it will look better than the original 72dpi scan.
Same applies for video. Just capture as high as you can. Capture DV if you want to save space.
And don't capture as MPEG-anything, capture it raw, and compress it later. This way you can do a twopass, or six-pass if you want, encode. Not only that, but if you capture low-res MPEG-2, and then upscale it, and re-encode it for a DVD, thats two generations of compression, looks like shit. Capture Hi-Res raw, then downscale to DVD size, or just cap at DVD res to begin with (should be sufficiant), and compress.

[trevlac]

You will see higher quality if you capture at a higher resolution.

IMO -- This is not true.

Here is another experiment. Capture a black screen at 100, 200, ... 720.

Do you see a difference except for the noise ? Probably not. That is because there is no detail to see.

Next question is how much detail is in a VHS recording. The detail is limited to ~ 320x480(576). 352x480 still gives you 10% buffer (which you should probably have).

So in theory ... you don't need more than 352x480 for VHS. In practice it depends upon what your equipment does, and how good your source is, and what your process entails. Simply run a test using both and see. Pick what you like.

Try Printing something on a laser printer at 72dpi, then scan it at 72dpi, and scan it at 300dpi. Even though the printed material was only 72dpi to begin with, the 300dpi scan looks better. Resize the 300dpi scan down to 72dpi, it will look better than the original 72dpi scan.

Interesting test. It would be more fair if you sampled at 2x the analog resolution + say 10%. 72 * 2 +10% ~ 160dpi. Also, if you resize down, it depends upon how you resize.


BTW: The easy answer is capture high. That way you don't have to worry about all the if's and's or but's. For example, TV source can have more detail than will fit into a 352 window. Does it? Test and see.

[SaSi]

trevlac,

you mentioned that VHS provides a detail of 320 x 480(576 for PAL).

I believe you are incorrect here.

The best VHS recorders go as far as 300~320 lines and only Super VHS theoretically - it's a tape thing - can provide something in the range of 400 - 420 lines.

This is for SP recordings. LP recordings are worse.

The problem is that with DVD, one can either go to 240(288) or 480(576) lines. Since 240 is too little even for normal VHS tapes, 480(576) has to be selected, even if it is more or less an overkill.

[lordsmurf]

Analog "lines" and WxH digital resolution are different. No relation, in terms of numbers. The "lines" is also max of the signal, not really the average.

I will say trevlac is going a bit too high for VHS though, that theoretical number (almost 350 res) is never really reached in practice. It's still much, much softer than 352x480, far greater than 20 pixels. It's in the upper 200's more likely. The only way to get better VHS captures is to use resolution boosters and detail enhancers between the VHS player and digital captures.

[Wilbert]

I would actually have to agree with this. Some cards cannot resize very well. BT8x8 chipsets are a perfect example.

If you know your card is good (like an ATI or Hauppauge), then capture any resolution allowed.

1) Perhaps you can provide us two screenshots (containing text; capped from VHS) (352x576 and 720x576). Then everyone can see your second statement is false.

2) BT8x8 resizes fine at/above 400x576.

3) There are hauppauge cards with a BT878 chip I actually have one.

@SaSi,

The best VHS recorders go as far as 300~320 lines and only Super VHS theoretically - it's a tape thing - can provide something in the range of 400 - 420 lines.

This is for SP recordings. LP recordings are worse.

The problem is that with DVD, one can either go to 240(288) or 480(576) lines. Since 240 is too little even for normal VHS tapes, 480(576) has to be selected, even if it is more or less an overkill.

The 300-320 lines is *horizontal* resolution, not vertical. Besides that, read lordsmurf comment.

[iantri]

(Sorry about the size of the pictures.)

This is interesting. I believe lordsmurf is correct. The following images were taken with an ATI TV Wonder VE (a BT878 card, with btwincap drivers), compressed using Photoshop, JPEG Level 9, the 352x480 image was resized for comparison purposes with the "Bicubic Sharp" scaling method. A 352x480 and 704x480 capture were used to keep the same aspect ratio. No deinterlacing or any other sort of manipulation was done. Source is SP VHS, through VHS VCR via composite video. Here is the 352x480 image (scaled to match 704x480 image, unscaled here) followed by the 704x480 image:




Clearly, the 704x480 image is better. (Any I don't think there is any point in claiming that the resizing of the 352x480 image caused quality loss; method was Bicubic Sharp)

Additionally, to support the theory that a good 352x480 image contains all the possible, I resized the 704x480 image down to 352x480 and then back to 704x480. There is no discernable difference in quality between the two.

Original and rescaled.

Lordsmurf, I'm not sure what you are saying about resize quality in the card; are you saying that the cards actually rescale the image horizontally from full-D1 resolution to your desired size? I would think that it would just sample fewer pixels from the analog image..

[lordsmurf]

Yes.

Another thing you have to understand is some cards have artificial sharpening enhancements. The BT8x8 chips with certain drivers at certain sizes kick them in. Because of some things I see in the water, I think your 720 is also being sharpened, in addition to just poor 352 from the card. Double punishment.

Supposedly there's a way to turn down or turn off the sharpening. Satstorm talked about it some long ago. It's not always a bad thing, only when it increases noise. In this case, I'd say it was a good thing for you, as your source started pretty clean. I have a SignVideo DR-1000, so I do this in hardware, actually. Sometimes.

Wilbert, I had some files I was working on in May. I'm not wrong. But much like the blank media gallery images, the works-in-progress were lost with a hard drive crash. When I get time, I have to redo all those tests again. It's on the list, will be on my site in the buying guides.

[Wilbert]

This is interesting. I believe lordsmurf is correct. The following images were taken with an ATI TV Wonder VE (a BT878 card, with btwincap drivers),

1) As I aaid, if you are comparing bt878 caps you should compare 704x480 and 368x480 (PAL 400x576). Lower sizes are blurred very much. We think that a vertical resizer is turned on (when capping lower at these sizes).

2) I hoped someone would post some ATI (theater chip).

[SatStorm]

VHS, VHS, VHS ... The same question over the years....


VHS is about 240 x 300, interlace, scretch in a 720 x 576 interlace Canvas.
SVHS is about 320 x 400, interlace, scretch in a 720 x 576 interlace canvas

This is the only way to try to determine analogue (VHS) to digital and understand it somehow. It is more of a practical way, most technofreaks don't really like that kind of "determination".


The best we can do when we try to capture VHS / SVHS (and any analogue source in the matter of fact...), is to capture the Canvas and then somehow reconstruct the real info from it.

This is clear and easy for the SVHS sources: If you resize and filter correct, you end up with 352 x 576/480 lines, which is very close to the SVHS reality.

The problem is with VHS
There are advance ways to do it, but this is possible only with PAL for real: The reason is the interlace barrier, the vertical 280 lines. PAL use 288 lines but NTSC only 240, so this "reconstruction" is not possible with NTSC. Also, only few standalones support correct those 288 interlace lines PAL can offer.

So, we end up using 352 x 576/480 as our target framesize for VHS. It is an overkill but the only thing we can do for NTSC. For PAL, it is more of a choice, so to have less issues not because of the standards, but because of the bad decoding the cheap commercial DVD standalones do.

[Wilbert]

VHS is about 240 x 300, interlace, scretch in a 720 x 576 interlace Canvas.
SVHS is about 320 x 400, interlace, scretch in a 720 x 576 interlace canvas

This is the only way to try to determine analogue (VHS) to digital and understand it somehow. It is more of a practical way, most technofreaks don't really like that kind of "determination".

It's a wrong determination. Vertically you need the full size. Horizontally, you need at least about 300 (VHS) and 500 (SVHS)[*], provided the card's resizer is good (for ati and bt8x8 you need larger sizes).
[*] http://www.doom9.org/capture/introduction.html

The reason is the interlace barrier, the vertical 280 lines.

Could you clarify and give some references? I never have heard of this.

edit: above I meant "2) I hoped someone would post some ATI (theater chip) PICS".

[Wilbert]

Lordsmurf, I'm not sure what you are saying about resize quality in the card; are you saying that the cards actually rescale the image horizontally from full-D1 resolution to your desired size? I would think that it would just sample fewer pixels from the analog image..

They sample internally at a much higher samplerate and downsize it to the requested capture size.

example: for bt8x8/cx2388x cards: NTSC: 28.64 MHz, and PAL: 35.48 MHz.

http://www.doom9.org/capture/sizes_advanced.html (5.2)

[SatStorm]

Just when I finished saying that many don't like that practical determination, a doom9 forum member jumps, by linking us to doom9....

Ask at doom9's excellent forum about the interlace barrier. They have plenty resourses there to link you (that is their way).
You won't like the way I'm gonna answer you anyway....