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-   -   Capture VHS to digital cropped? (http://www.digitalfaq.com/forum/video-capture/9433-capture-vhs-digital.html)

Brandonrowe14 02-09-2019 02:41 PM

Capture VHS to digital cropped?
 
2 Attachment(s)
Hello,

I'm working on a project to convert around 25 hours worth of family footage from VHS to digital. I bought a VC500Mac and am using the VideoGlide Capture software. The image that I am getting looks pretty good, but I seem to be losing a small portion of the left and right sides of the video? This isn't the worst thing, but I'd like to create as perfect replicates as I possibly can.

I looked at the threads stickied on this section and suspect this has something to do with overscanning? I'm totally new to this detailed level of video conversion so I apologize if I'm missing something very obvious.

For comparison, I've attached a picture of the image directly from my TV and a screengrab of the capture below. Any help would be greatly appreciated.

forknor 02-09-2019 03:13 PM

Overscan
 
If you look at the image itself on the TV vs in your capture, you can see that the content is equivalent, but is just:

- slightly stretched horizontally on the TV
- has the black bars removed on the TV

These black bars are trimmed on the TV due to overscan (the analog signal includes blank areas under the assumption that TVs all only display a portion of the image)

The stretching on the TV is either just a setting of the TV (stretching to fill it's screen), or may be the TV taking the display aspect ratio/pixel aspect ratio into account (analog sources do not typically use square pixels).

Brandonrowe14 02-09-2019 03:20 PM

I still think it's cropping some of the content
 
2 Attachment(s)
Thanks forknor. I see that the image is stretched on the TV, but I also believe some of the image is missing on the capture. I've attached two images that point out the detail in the right side of the image. If you look at the content in the circle of the TV photo, you'll notice that it is completely absent from the capture image. Should I be capturing at a different aspect ratio? As far as I know, this is just a normal VHS.

sanlyn 02-09-2019 05:28 PM

Quote:

Originally Posted by Brandonrowe14 (Post 59279)
Thanks forknor. I see that the image is stretched on the TV, but I also believe some of the image is missing on the capture.

The aspect ratio in the screen capture displays the correct Display Aspect Ratio. But the TV image is stretched. Is your TV really sub-par or just not smart enough to display aspect ratios correctly? I'd buy a better tv. BTW, images do not have overscan. Overscan is a property of display panels, not of images. Today's HDTVs employ overscan edge masking by default. If your TV does not allow defeating overscan thru its remote, get a better tv.

The bottom border noise is head-switching noise. It's common with VHS. There might also be thinner or thicker side borders depending on the player or the capture device; ordinarily, SMPTE and other tape standards use only the central 704 pixels of a captured 720-pixel wide image. If you're capturing to square-pixel, you'll see a commensurate amount of side border in the resulting image. How borders are treated is discussed and illustrated in several hundred threads in this forum. In Avisynth and VirtualDub, unwanted border material is removed after denoising and color correction, then replaced with new border pixels that preserve the original frame content (http://www.digitalfaq.com/forum/vide...erly-crop.html). Overmasking actual image content and/or resizing to fill the frame (and thus altering the DAR) is characteristic of beginners.


Your posted images indicate invalid digital video levels in your capture, or else your displays are in serious need of calibration.

If you want a true image of what a video frame actually looks like, unaltered, select a frame in VirtualDub, copy it to the clipboard, and use anything you want to make an image for posting. Frame captures can be saved in Windows Paint or similar apps as jpg or png.

Brandonrowe14 02-09-2019 06:06 PM

Brand New LGTV
 
Thanks sanlyn! My TV is actually brand new. It's a smart LGTV that I purchased about 2 months ago.

Even though the display from the VHS to the TV is a little stretched, I'm not terribly concerned with the VHS to TV display because I'd like to eliminate the VHS player after converting the tapes to digital.

Thanks for clearing up the overscan issue. Since the TV is displaying the complete image, I don't think that's a problem for me.

I'm still unclear as to why the VHS to Mac capture is cropping the image down ever so slightly?


Quote:

Originally Posted by sanlyn (Post 59281)
The aspect ratio in the screen capture displays the correct Display Aspect Ratio. But the TV image is stretched. Is your TV really sub-par or just not smart enough to display aspect ratios correctly? I'd buy a better tv. BTW, images do not have overscan. Overscan is a property of display panels, not of images. Today's HDTVs employ overscan edge masking by default. If your TV does not allow defeating overscan thru its remote, get a better tv.

The bottom border noise is head-switching noise. It's common with VHS. There might also be thinner or thicker side borders depending on the player or the capture device; ordinarily, SMPTE and other tape standards use only the central 704 pixels of a captured 720-pixel wide image. If you're capturing to square-pixel, you'll see a commensurate amount of side border in the resulting image. How borders are treated is discussed and illustrated in several hundred threads in this forum. In Avisynth and VirtualDub, unwanted border material is removed after denoising and color correction, then replaced with new border pixels that preserve the original frame content (http://www.digitalfaq.com/forum/vide...erly-crop.html). Overmasking actual image content and/or resizing to fill the frame (and thus altering the DAR) is characteristic of beginners.


Your posted images indicate invalid digital video levels in your capture, or else your displays are in serious need of calibration.

If you want a true image of what a video frame actually looks like, unaltered, select a frame in VirtualDub, copy it to the clipboard, and use anything you want to make an image for posting. Frame captures can be saved in Windows Paint or similar apps as jpg or png.


hodgey 02-09-2019 07:53 PM

It could be some settings in VideoGlide. I don't remember if VideoGlide has crop settings, though at least in my screenshots of it in an older thread it doesn't crop the image. I can have a look into it once I have the time.

hodgey 04-11-2019 06:14 AM

Almost forgot about thisone.

I checked with the two VC500 mac dongles we got. They have different hardware inside so it seems there are several revisions of these.

One has a Philips SAA7113 + the standard empia usb bridge and audio chips. This one captures to 720x576 no problem.

The other (presumably newer one), which has a single empia em2980 chip refuses to cature to 720x576, it only works with 640x480, and I think it also seemed to crop a bit off at least one side. Interestingly it works fine with 720x576 on windows, so it seems it's some software issue. Granted, the quality is not quite as good as the other one.

lordsmurf 04-11-2019 07:38 AM

Quote:

Originally Posted by hodgey (Post 60731)
Almost forgot about thisone.

I checked with the two VC500 mac dongles we got. They have different hardware inside so it seems there are several revisions of these.

One has a Philips SAA7113 + the standard empia usb bridge and audio chips. This one captures to 720x576 no problem.

The other (presumably newer one), which has a single empia em2980 chip refuses to cature to 720x576, it only works with 640x480, and I think it also seemed to crop a bit off at least one side. Interestingly it works fine with 720x576 on windows, so it seems it's some software issue. Granted, the quality is not quite as good as the other one.

I knew this had to be the case. There have been too many reports of VC500 issues, such as AGC. The trick is to now see if ANY external clues can be found to see which version you have (or will get).

hodgey 04-11-2019 07:49 AM

The VC500 mac dongles (white) have completely different hardware (empia-based) to the normal (black) VC500 which use a conexant chip (other than some very early ones according to the linuxtv wiki).

sanlyn 04-11-2019 12:21 PM

Quote:

Originally Posted by lordsmurf (Post 60733)
I knew this had to be the case. There have been too many reports of VC500 issues, such as AGC. The trick is to now see if ANY external clues can be found to see which version you have (or will get).

Anyone who uses a mac for analog capture should expect problems. It's a wonder they get anything at all.



I have several years of excellent capture work with my two VC500's, and no AGC anywhere in sight. Yes, two. The first was a casualty of my own making (I knocked it off a desk and stepped on it in the dark on my sleepy way across a room at 3 AM). The second is still going strong in one XP machine when my All In Wonder is busy, and on occasion it's OK with Win7 and Win10 laptops.


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