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-   -   Black Dots in Hi8 Capture (https://www.digitalfaq.com/forum/video-capture/10780-black-dots-hi8.html)

edoroom 07-07-2020 04:31 AM

Black Dots in Hi8 Capture
 
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Hi,
After finally finishing capturing all the VHS Tapes I had and also all the Mini-DV tapes I started working on all the Hi8/8 Tapes I have,However there is something really disturbing that I'm not sure what causing it,In the Camera screen I cant really notice it however it's not really telling anything hehe,
So far I captured like 4 tapes and 3 of them having that weird issue in some part of the video and it's like black dots all over the screen,I attached a 10 sec sample video,
I tried to search in this forum and videohelp for anyone who had similer issue,Some suggested maybe different S-Video cable but I doubt it's really related to the cables,My question basically if it's something in the flow I'm using to capture making it or it's just the tapes?
Current flow is -

Sony CCD-TRV228E (Pal Camera with TBC and DNR enabled) --> Svideo to 1T-TBC --> ATI 600 Capture card

It should be the ideal flow as far as I understood,I wonder if I really should added the External TBC to the flow or let the camera handle everything however I cant really tell if it's doing any side effects,
What's really disturbing is that issue with the dots which I have no clue why it's coming like that in different parts of the video ;/:screwy:

Will apperciate the help! Thank you ;)

-Edit -
Not sure if it's related but this tapes are Video8 so it maybe not right to say "black dots in hi8 capture" as the tapes I currently see that issue are Video8

keaton 07-07-2020 11:53 AM

I could guess and say it's the tape and those are what you call dropouts or comets from tape aging. But to be sure, I'd try a little process of elimination to be sure it's not something else. Try connecting tape player output straight to a TV or to the capture device in Virtualdub Preview mode (if possible, otherwise just make another capture), just to see if the dots are still there. If you have another camera, you could try that. If it truly is just on the Video8 tapes (which predated Hi8), and not the Hi8 tapes, I would suppose it's just the tapes are older and are starting to show signs of deterioration.

If you cannot remove these dropouts/comets from the capture, it looks like you can get rid of most of them in post processing in avisynth. I did a quick pass of this test.avi through RemoveDirtMC avisynth plugin, and got most of the dots to disappear using fairly conservative settings. There may be other ways to fix dropouts. This is just one that's been mentioned a lot in the forums over the last few years.

Code:

v=AVISource("test.avi",pixel_type="YUY2")
AssumeTFF(v)
AssumeFrameBased(v)

ConvertToYV12(interlaced=true)
SeparateFields()
e=SelectEven().RemoveDirtMC(30,false)
o=SelectOdd().RemoveDirtMC(30,false)
Interleave(e,o)
AssumeFieldBased()
Weave()

One sacrifice in this example is you have to convert from YUY2 (4:2:2) to YV12 (4:2:0) in order to use the plugins used by the RemoveDirtMC.avs file which would go in your Avisynth plugins folder. I think there's multiple forum posts out there with this script file. I found a 2018 post that referred to this link http://www.digitalfaq.com/forum/atta...emovedirtmcavs You'd also need some other plugins that are used by RemoveDirtMC. Refer to this forum post. http://www.digitalfaq.com/forum/vide...html#post53877 I think that's all you'd need to get the above script working. Maybe there's a more recent version of plugins that don't require down-converting to YV12. Haven't checked on that in a while. If not, I guess, at worst, you could do this at the very end of your video filtering chain after you've done everything else you can in YUY2. Although lossy formats (i.e. MPEG2) can support 4:2:2, a lot of the time they are encoded with 4:2:0 anyway. What's important is to do the more important color related filtering in Virtualdub or avisynth in 4:2:2 before decimating the color info to 4:2:0.

Best of luck to you.

cbehr91 07-08-2020 12:31 AM

You could attempt to clean it up with software, but its likely a hardware problem with the camera. You could try cleaning the head. On a V/Hi/D8 camcorder it's pretty easy. I use Chamois swabs I bought on Amazon, dip the tips in isopropyl alcohol, then spin the head with your hand while lightly pressing the swab up against the head (it's supposed to move freely). If you get lots of gunk, repeat.

On many of those cams the lock nut on the pinch rollers are known to to bad, which can cause tapes to just play snow/blue screen.

edoroom 07-08-2020 05:26 AM

Hi,
Thanks both of you for the answers!
I just verified everything I could from the hardware side as suggested and unfortunatly @Keaton was right with his answer,
It's the tape indeed ;( and it seems many of my tapes having that issue.. I hoped it's something related to the hardware but seems not..
I tried using another camera with has the same functions (TBC+DNR and svideo output)
Tried 2 different capture softwares (Virtualdub and AmaercTV)
Tried to see the output directly from the composite without the external TBC and tried with the Svideo output with the external TBC,
In all cases this black dots are all over the screen I hope the suggested script can really solve that issue as much as possible without taking hit on the video it self..
Thanks again!

cbehr91 07-08-2020 11:50 AM

What brand of tape? For some reason's Sony's 8mm tape stock in the 90s was very suspect.

edoroom 07-08-2020 12:47 PM

Couldnt really relate that issue to a certain tape type..
So far I did 7 tapes,
4 of them had that issue,2 of them "Sony MP120" and 2 of them are TDK tapes..
However from what I understood from my father who recorded all of the things is that in that time he got most of the tapes from the place he worked at where they gave him from time to time the tapes that were used in the security camera so I guess this tapes had so many re recording on them and the time that went.. That's probably why they became like that ;(
I just hope the script provided will work well to minimize this black dots ;D


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