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  #1  
03-20-2019, 02:23 AM
ofesad ofesad is offline
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Hi people!

Ofesad here from Argentina.

Today I tested my S-Video output mod to a non-svideo non-svhs vcr.

The deck in question is a SONY SLV-L86HF (also known as or L86AR), 6 head stereo with "sapphire tape cleaner", It plays PAL / NTSC vhs's and it has a switch so it can output NTSC or PAL-N signal.

So, here's the "FrankenSony":



However this post is not about how I mod it, it's more about comparing the image quality of the Svideo mod vs the composite output.

I'd like your inputs regarding the picture so I can see to improve the mod to obtain a better picture quality.
What you see, what you don't see, what you think it could be improved, ...


Here's a picture comparision.


and here a comparision of the video files:



The Svideo file has 15~18% higher bitrate.


And here are the videos.
Captured with Pinnacle Moviebox on VirtualDub and compression with Huffyuv. RAW material, no filters.
COMPOSITE VIDEO (296 Mb)

SVIDEO VIDEO (340 Mb)


Thank you for reading and your inputs!

Ps: Please don't be mean with the comments!


Attached Images
File Type: jpg CAPTURE-COMPARE.jpg (41.9 KB, 63 downloads)
File Type: png COMPARA_COMPOSITE_SVIDEO.PNG (11.6 KB, 63 downloads)
File Type: jpg IMG_20190320_0411204.jpg (62.2 KB, 61 downloads)
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The following users thank ofesad for this useful post: wimvs (03-20-2019)
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  #2  
03-20-2019, 08:14 AM
hodgey hodgey is online now
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Interesting, hope you can give us some info to where you tapped the Y and C from on this deck. I know many newer deck do all the processing including Y/C mixing inside an IC where it can't be tapped, but there seem to be exceptions.

I've been looking at doing an S-Video mod on my JVC HR-J658 as it seemed it was possible. The PCBs are shared between the lower and higher-end models of those so it seemed the Y and C outputs to the SVHS board were present, and with some probing at leasat the Y channel was there. Haven't gotten around to tinkering any further with it.
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  #3  
03-20-2019, 08:44 AM
dpalomaki dpalomaki is offline
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The s-video higher bit rate is consistent with the increased detail and noise content (not filtered out as a result of the bandwidth limitation of the composite video processing in the VCR and capture device). There is almost never a reason to capture via composite video connections. It give you more with which to work in the restoration process.

An interesting project for folks with similar VCRs.
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  #4  
03-20-2019, 10:55 AM
sanlyn sanlyn is offline
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Quote:
Originally Posted by dpalomaki View Post
The s-video higher bit rate is consistent with the increased detail and noise content (not filtered out as a result of the bandwidth limitation of the composite video processing in the VCR and capture device). There is almost never a reason to capture via composite video connections. It give you more with which to work in the restoration process.

An interesting project for folks with similar VCRs.
Ditto.

@ ofesad:
Quote:
Originally Posted by ofesad View Post
And here are the videos.
Captured with Pinnacle Moviebox on VirtualDub and compression with Huffyuv. RAW material, no filters.
COMPOSITE VIDEO (296 Mb)

SVIDEO VIDEO (340 Mb)
We ask that you don't post off-site. When your off-site videos disappear, your comparison won't make sense. Most of this thread would be useless.

It's strongly recommended that RGB should not be used for VHS capture. VHS isn't RGB, nor is RGB an entirely accurate representation of your VHS original. VHS is YPbPr, or the equivalent of YUY2.

I've taken the liberty of attaching a slightly edited lossless YUY2 of the posted videos so that your notes won't be entirely useless if your offline posts go away.

Thanks for the comparison.


Attached Files
File Type: avi COMPOSITE_CAPTURE_CUT_YUY2_Lagarith.avi (83.28 MB, 2 downloads)
File Type: avi SVIDEO_CAPTURE_CUT_YUY2_Lagarith.avi (94.60 MB, 2 downloads)
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  #5  
03-20-2019, 11:05 AM
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lordsmurf lordsmurf is offline
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He asked me about the file size before the post, and I said something that larger needs to be on our file server instead. So he was doing well. I'll be downloading/uploading those in a day or so.

But ~300mb down to ~90mb is quite a feat. I want to look more at what happened there, when I get the time. Was it all editing, or did RGB have something to do with the shrinkage? I know Lagarith can be 25% smaller, but we're talking 1/3rd reduction here. Interesting.

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  #6  
03-20-2019, 11:28 AM
hodgey hodgey is online now
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I'm seeing a lot of diagonal lines in the capture, as if the y channel contains the color signal or at least something is not filtered out of it.
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  #7  
03-20-2019, 11:38 AM
ofesad ofesad is offline
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Quote:
Originally Posted by hodgey View Post
Interesting, hope you can give us some info to where you tapped the Y and C from on this deck. I know many newer deck do all the processing including Y/C mixing inside an IC where it can't be tapped, but there seem to be exceptions.

I've been looking at doing an S-Video mod on my JVC HR-J658 as it seemed it was possible. The PCBs are shared between the lower and higher-end models of those so it seemed the Y and C outputs to the SVHS board were present, and with some probing at leasat the Y channel was there. Haven't gotten around to tinkering any further with it.
No problem! Aint that hard, but some soldering skills are needed.

Actually this mod begun just with the idea of using this VHS, that for me personally has give me always much joy and the picture always seemed pristine, even in composite.

Most SONY's SLV models should be capable of this mod, at least the 6 Head models, would have to check more manuals to be sure, but I would guess that there isn't much difference.

Sadly I don't have JVC. Here in Argentina JVC decks are kindda rare. Most are Panasonic, Sony, Philips or many other brands.
I couldn't find the HR-J658 service manual on the internet. If you have it I could take a peek and give you the tips of what to do.

Quote:
Originally Posted by dpalomaki View Post
The s-video higher bit rate is consistent with the increased detail and noise content (not filtered out as a result of the bandwidth limitation of the composite video processing in the VCR and capture device). There is almost never a reason to capture via composite video connections. It give you more with which to work in the restoration process.

An interesting project for folks with similar VCRs.
Thank you dpalomaki! Really appreciated your input.

It all begun as an experiment, but now I am thinking to add more features like Noise Reduction, filtering or some Sharpness control.

Also, since SVHS are becoming harder and harder to find (and even if you find one, could be for parts or overly used), this would be a good solution for bring life back to common VCR's and getting a better picture. Probably not as good as SVHS decks, but still an intemediate.

The mod would fit many others VCRs too. Would have to check more manuals but, you can bet for Philips, Panasonic and JVC's VCR would be capable of being modded too.

Quote:
Originally Posted by sanlyn View Post

It's strongly recommended that RGB should not be used for VHS capture. VHS isn't RGB, nor is RGB an entirely accurate representation of your VHS original. VHS is YPbPr, or the equivalent of YUY2.

I've taken the liberty of attaching a slightly edited lossless YUY2 of the posted videos so that your notes won't be entirely useless if your offline posts go away.

Thanks for the comparison.
Thank you for noticing. I would double check next time!

It's weird, I just checked VirtualDub and huffyuv and it's all set to YUY2.

It was around 4am here when I posted the video, so maybe was a little sleepy and changed the config. Sorry for the screw up.

Thank you for taking the time to improve the material!

Quote:
Originally Posted by hodgey View Post
I'm seeing a lot of diagonal lines in the capture, as if the y channel contains the color signal or at least something is not filtered out of it.
Thank you for noticing! Today I will be doing some testing, changing values and see if it improves!

Last edited by ofesad; 03-20-2019 at 11:56 AM.
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  #8  
03-22-2019, 01:11 AM
ehbowen ehbowen is offline
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Do you happen to have any idea whether such a mod would be possible on a Sony SVO-965P duplicator? I bought it so that I could have some way to play PAL tapes, but if it would be possible to modify it for better quality I'd be interested.
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  #9  
03-22-2019, 12:38 PM
NJRoadfan NJRoadfan is offline
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It would be a nice mod for Betamax decks since so few have S-Video output. I know someone out there has done it, but never published a how-to or any details. Most older decks should have the chroma and luma separated within the deck after de-modulation and amplification, the trick is finding where that point is to tap it.
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  #10  
03-22-2019, 12:54 PM
dpalomaki dpalomaki is offline
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In general, service manuals for most common VCRs, including commercial/professional/industrial models can be found on line, often for a nominal price $10 or so. They will usually contain circuit diagrams and if one knows what one is doing, the diagrams can be read to determine whether or not the Y and C signals can be readily picked off for amplification and redistribution.

However, care needs to be taken to ensure proper impedance, frequency response, and headroom in the signal path. This is necessary to preserve standard levels and phases for color decoding.
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