Quantcast 352x480 vs 720x480 for VHS captures - digitalFAQ Forum
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12-23-2013, 11:42 PM
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I keep seeing 352x480 suggested for VHS captures, but I haven't really seen any comparisons or examples. I tried capturing like that but either I didn't set it up right or its supposed to look very rectangular. What are your thoughts?
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12-26-2013, 11:56 PM
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You're not supposed to view it with 1:1 square pixels (or 720x480 or 704x480 for that matter). Once you encode for your delivery medium (DVD, Blu-ray) you need to tell the encoding software the correct aspect ratio of the source and then the player will respond accordingly.
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12-27-2013, 12:14 AM
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Quote:
Originally Posted by msgohan View Post
You're not supposed to view it with 1:1 square pixels (or 720x480 or 704x480 for that matter). Once you encode for your delivery medium (DVD, Blu-ray) you need to tell the encoding software the correct aspect ratio of the source and then the player will respond accordingly.
I was looking at this:
352x480 vs 720x480 to capture MPEG2 for DVD

and wondering the real benefits of either, I had mixed up resolution vs aspect ratio, but now I'm wondering if I resize if I will lose details (Lag captures). I will not be making DVDs, but instead making a raid setup with the lossless captures stored.
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12-27-2013, 03:14 AM
msgohan msgohan is offline
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When I've compared my own captures I've found details that disappear when I resize below 352x480 but never any details that require more resolution than that.* This is capturing at 720x480, cropping 16 pixels of black borders, and halving the horizontal resolution. (Few capture devices these days support lower resolutions, and I prefer to do processing at the highest res and then only resizing down at the end.)

*Having said that, I just looked at another tape and the edges of some computer generated lettering looked softer at 352, but I haven't verified that it isn't just a case of "detail" being created by a sharpener in the VCR.

It's easy enough to try for yourself using Avisynth and the Interleave command if you've got some tapes captured.
Code:
#Compare 720 width to 360 width (i.e. 352 with no crop)
Interleave(last.Subtitle("Original"),LanczosResize(width/2,height).LanczosResize(width,height))
One extremely minor advantage to 720x480 is that with some tapes, the picture is very slightly wider than 704 pixels so you get to keep a handful of pixel columns that you'd have to crop to be able to use 352. Another is that you don't have to upscale 720x480 to put it on a Blu-ray Disc for sharing with other people. I can't think of any others at the moment.

For lossless, the advantage of 352x480 is of course filesize. The extra pixels are mostly unpredictable noise, so you should be able to cut your sizes to 55-60% of their initial size without denoising.

Last edited by msgohan; 12-27-2013 at 03:51 AM.
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12-27-2013, 08:45 AM
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So just to confirm, if you capture at 352x480, it sounds like you get the same resolution, you don't really lose any quality. I only ask because it almost sounded like deinterlacing with the discard method, but it sounds like that only applies to already capped videos.

Is there a good way to resize my 720x480 captures without losing quality? They are lag captures and I'm wondering if the filters will compensate.
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12-27-2013, 09:01 AM
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The only card I'd use to capture 352x480 is the ATI All In Wonder cards. The actual chip is almost 704x480, and the 720x480 is actually the padded stream. You can resize 720 to 352 in VirtualDub or Avisynth, and it'll be fine.

Most often "details" are just imagination, or the product of an artificial sharpener. Or both.

I'd capture 720 if SD Blu-ray is the destination.
I'd capture 352 if analog tapes are the source, and DVD is the destination.

Sometimes even the "720x480" of a DV camera is 352x in actuality. Why? The camera lens/glass and sensor wasn't any good. The video palette may be 720, but the actual image detail is not.

Huffyuv is faster and smaller at 352, as msgohan pointed out.

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12-27-2013, 11:04 AM
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Quote:
Originally Posted by lordsmurf View Post
The only card I'd use to capture 352x480 is the ATI All In Wonder cards. The actual chip is almost 704x480, and the 720x480 is actually the padded stream. You can resize 720 to 352 in VirtualDub or Avisynth, and it'll be fine.

Most often "details" are just imagination, or the product of an artificial sharpener. Or both.

I'd capture 720 if SD Blu-ray is the destination.
I'd capture 352 if analog tapes are the source, and DVD is the destination.

Sometimes even the "720x480" of a DV camera is 352x in actuality. Why? The camera lens/glass and sensor wasn't any good. The video palette may be 720, but the actual image detail is not.

Huffyuv is faster and smaller at 352, as msgohan pointed out.
My blackmagic intensity usb 3.0 won't capture at anything less than 720x480, so I've been compressing with Lag in VirtualDub. They will be remaining on hdd and played through a computer, so if I can retain quality with smaller file sizes it would be better. I will try it out and let you know.

I can't figure out how to properly resize my video in virtualdub. I have been playing with the filters with no luck.
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