Quantcast Is VCR actually effecting output video quality? - digitalFAQ Forum
  #1  
09-30-2020, 06:36 PM
connorinspace connorinspace is offline
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Hello, apologies for the possible newbie question. I am new here, but not new to video. I have read the pinged posts relating to VCR buying, but am in need of a bit more specific advice.

My scenario:

Does my grandma's cheap VCR (that works just fine) negatively affect the captured video quality in comparison to a true professional VHS deck?
Is a cheap VCR really outputting a lower quality signal than the professional decks? Notwithstanding the difference in build quality/reliability/Effects/TBC.

1) I am capturing using an AJA KONA LHE+ I/O. S-VIDEO input. TBC in VCR is not an issue for me, I have external devices in my signal chain that can handle that.

2) I am not interested in using any special, non-standard smoothing or filtering effects in the VCR. My mindset is archival: capture the VHS tape in its true raw form.

3) BONUS: Ideally, I would love to capture the edges of the VHS frame. Comparable to an "overscan" with sprockets in the film telecine world. If a pro-level device could help with this, it would convince me to switch.
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  #2  
09-30-2020, 08:23 PM
dpalomaki dpalomaki is offline
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What is your signal chain - please include make and model and software being used?

Assuming both machines are well tuned and performing according to spec, a professional, prosumer, or high end consumer S-VHS VCR will give better output than a plain old VHS deck. This applies to the recommended machines.

For starters, VHS video on tape is recorded in what amounts to a Y/C (s-video) mode. The composite (yellow jack) video output of the VHS VCR electrically combines the Y/C signals into the composite signal only to have it separated again in the TBC and/or capture system. This is extra processing that can add distortion, resolution loss, and noise. Beyond that the internal electronics and mechanics of the better machines generally will have better frequency response, less distortion, more accurate tracking, wider bandwidth, and lower noise.

That said, VHS machines tend to be old and often suffer the abuses of age, wear, component value drift, and lack of maintenance, so there is no assurance that a given used machine will perform to its capability. Further, recordings, especially home recordings, will suffer from what ever alignment quirks the original recorder had, and thus may play better on some machines than on other more accurately aligned machines.

Inability to capture the ovescan area might be a limitation of your capture device/software, not the playback VCR. Some setups may crop the edges. Most TV do not display the overscan areas unless specifically set up to do so.
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  #3  
09-30-2020, 09:33 PM
Formica Formica is offline
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Quote:
Originally Posted by connorinspace View Post
I am capturing using an AJA KONA LHE+ I/O. S-VIDEO input.
I have had no luck getting my IO to capture video! are you using VTR XCHANGE?
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  #4  
09-30-2020, 10:26 PM
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Quote:
Originally Posted by connorinspace View Post
Does my grandma's cheap VCR (that works just fine) negatively affect the captured video quality in comparison to a true professional VHS deck?
Yes, and very negatively, not just slightly.

Quote:
Is a cheap VCR really outputting a lower quality signal than the professional decks? Notwithstanding the difference in build quality/reliability/Effects/TBC.
Substantially lower ... and the better deck is better because of build quality, tolerances, TBC, Y/C.

Quote:
1) I am capturing using an AJA KONA LHE+ I/O. S-VIDEO input. TBC in VCR is not an issue for me, I have external devices in my signal chain that can handle that.
Line TBC in the VCR is not external frame TBC. Different functions, you need both.

Quote:
2) I am not interested in using any special, non-standard smoothing or filtering effects in the VCR. My mindset is archival: capture the VHS tape in its true raw form.
You'll mostly be capturing noise in an "edit" mode. Noise is not inherently "raw" capturing. In fact, noise is an issue obstructing RF projects. There are few use cases where you'd want to perform a no-NR capture, mostly in certain stabilizations that cannot tolerate any NR for best results.

Quote:
3) BONUS: Ideally, I would love to capture the edges of the VHS frame. Comparable to an "overscan" with sprockets in the film telecine world. If a pro-level device could help with this, it would convince me to switch.
No such thing exists. Some devices can give an extra 6 pixels, full 720x486, but that involves more post work to get a usable video. Sometimes that can be a benefit, if you're anal intent on getting a "full" image withour headswitching noise, but it's still no guarantee, and still depends heavily on what the VCR is doing.

Quote:
Originally Posted by dpalomaki View Post
For starters, VHS video on tape is recorded in what amounts to a Y/C (s-video) mode. The composite (yellow jack) video output of the VHS VCR electrically combines the Y/C signals into the composite signal only to have it separated again in the TBC and/or capture system. This is extra processing that can add distortion, resolution loss, and noise. Beyond that the internal electronics and mechanics of the better machines generally will have better frequency response, less distortion, more accurate tracking, wider bandwidth, and lower noise.


Quote:
will suffer from what ever alignment quirks the original recorder had, and thus may play better on some machines than on other more accurately aligned machines.
After converting many thousands of tapes, this is true far less than 1% of the time. The original recording deck is rarely ideal. Even when misalignment exists, I can extract a better quality signal by tinkering with my misalignment deck (S-VHS+TBC deck that is purposely never aligned, in order to match tapes that need this work --- I do a lot of these now, since mentioning it some years ago, but still less than 1%).

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  #5  
10-02-2020, 02:39 PM
connorinspace connorinspace is offline
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Quote:
a professional, prosumer, or high end consumer S-VHS VCR will give better output than a plain old VHS deck
Copy that. I understand S-Video out is a must. I guess my question is more about "high-end" consumer VCR's with S-VIDEO out. How do those compare to the professional VCR's?

Quote:
Line TBC in the VCR is not external frame TBC. Different functions, you need both.
Can you explain the difference, please? My expierience is that TBC is needed in some cases to allow digital devices to process the analog signal. But I have not heard that there are two different types of TBC?

Quote:
Some devices can give an extra 6 pixels, full 720x486, but that involves more post work to get a usable video. Sometimes that can be a benefit, if you're anal intent on getting a "full" image withour headswitching noise,
My use case is non-traditional. I would love to capture the headswitching noise. Post-processing time is not an issue for me. The more signal area captured, the better. An extra 6 pixels would be fantastic. Can you name any devices that allow this?
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  #6  
10-03-2020, 07:42 AM
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Quote:
Originally Posted by connorinspace View Post
Copy that. I understand S-Video out is a must. I guess my question is more about "high-end" consumer VCR's with S-VIDEO out. How do those compare to the professional VCR's?
Y/C, build quality, stability.
For example, you have less chroma skew/offset from a prosumer or pro deck.
Less timing wobbles.

Quote:
Can you explain the difference, please? My expierience is that TBC is needed in some cases to allow digital devices to process the analog signal. But I have not heard that there are two different types of TBC?
There's actually at least 3 kinds (frame, field, line).
Line TBC cleans the image.
Frame TBC cleans the signal.
You need both.

Quote:
My use case is non-traditional. I would love to capture the headswitching noise. Post-processing time is not an issue for me. The more signal area captured, the better. An extra 6 pixels would be fantastic. Can you name any devices that allow this?
Search the forum for posts from latrech on SDI and 720x486.
I don't suggest that route, but it's viable.

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  #7  
10-03-2020, 03:10 PM
latreche34 latreche34 is offline
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Quote:
Originally Posted by connorinspace View Post
My use case is non-traditional. I would love to capture the headswitching noise. Post-processing time is not an issue for me. The more signal area captured, the better. An extra 6 pixels would be fantastic. Can you name any devices that allow this?
By standard the active video area is only 704x480 give or take, I have come across only 2 tapes that had more than 480 lines of active video vertically, very rare. 6 extra lines doesn't give you more information, but it does give you the option to select your cropped 480 lines anywhere in the vertical domain to evenly split the noise between the top and bottom, Unlike capturing at 480 the noise is always on the bottom.

The same goes for 720, having extra 8 pixels of noise on each side gives you the option to select your active cropped 704 pixels evenly between left and right. From 704x480 resolution you can set the aspect ratio flag accordingly during encoding or resize to 640x480 which ever works for you.
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