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-   -   VHS Backup (http://eab.abime.net/showthread.php?t=105495)

Thalion 21 January 2021 13:13

VHS Backup
 
Hi there,

i just got some VHS Backup tapes. They where intended for this:
https://bigbookofamigahardware.com/b...t.aspx?id=1456

Now i'm thinking of a good solution to get them back on my Amiga or maybe WinUAE. I have a VHS-Recorder so i could write them back to my PC. Question is what filetype would be best to get the stored information working.

Hope you can help me with this.

Exodous 21 January 2021 15:50

To get the video back into your PC, you could use some capture software to capture the video - though it would have to save it effectively "raw" as any sort of modern video format will compress the data and probably lose the actual video "noise" you need.

However, unless you know how the data was stored / encoded within the video stream, it might be a task to get the data back.

I would suggest if you have the original hardware to plug between the VCR and the Amiga, then actually getting an Amiga is probably the most likely solution to work.


Just looking through my archives and I have some pointers for information in case it helps.

Thew author's web site is at:

http://www.hugolyppens.com/VBS.html

The manual is at:

http://www.amiga-storage.net/dl.php?...Manual-ENG.pdf

The software appears to be in TOSEC, available on the FTP server:

http://grandis.nu/eabsearch/search.p...xclude=&limit=

Thalion 21 January 2021 21:27

Thanks

Still the problem remains how to read the data without the VBS hardware.

Exodous 22 January 2021 13:13

You could use the "email me" link on the authors web page (linked above) and ask him if he has any ideas?

http://www.hugolyppens.com/

Toni Wilen 22 January 2021 13:38

Emulation side support would be easy if someone writes video stream to binary data converter. Adapter does nothing more than convert video signal to binary and routes it to Amiga serial receive port pin.

Conversion should not be that difficult, each visible scan line has 4*11 bits of data. 4*(start bit + 9 data bits + stop bit).

I might consider doing it if I get at least first few minutes or so of video from beginning of backup :)

roondar 22 January 2021 13:57

At that data resolution, a high enough bitrate might even allow compressed video to work reasonably well. Then again, uncompressed black and white (which I think this uses) PAL VHS is going to be around 24KB/frame* or around 4GB/hour if encoded as 1 bit per pixel.

That's a lot considering how little is stored in the backup by comparison, but clearly not impossible with today's technology.

*) VHS is equivalent to roughly 335×576 pixels per frame in PAL areas, so around (335x288)/8=12KB per field or 24KB per frame.

Toni Wilen 22 January 2021 14:14

One possible problem is finding digitizing device that handles interlaced frames separately (50Hz) instead of creating unusable 25Hz output..

roondar 22 January 2021 14:21

This is very true. I have a fairly new and not really all that cheap digitizer that was specifically marketed as a solution for recording retro games "accurately", with PAL/NTSC composite/S-Video support (it also supported component).

Imagine my surprise when I found out the device did automatic deinterlacing in hardware with no option to turn it off. Not only that, but it just blended the two fields together so it became really messy.

Thalion 22 January 2021 15:35

Quote:

Originally Posted by Toni Wilen (Post 1455800)
Emulation side support would be easy if someone writes video stream to binary data converter. Adapter does nothing more than convert video signal to binary and routes it to Amiga serial receive port pin.

Conversion should not be that difficult, each visible scan line has 4*11 bits of data. 4*(start bit + 9 data bits + stop bit).

I might consider doing it if I get at least first few minutes or so of video from beginning of backup :)

That sounds promising. I will digitize the VHS tape and send the file to you. What format would be suitable? MPG2 or better something else?

Sandancer 22 January 2021 15:48

I used to love that Program, pity I don't know what happened to all mine. Be nice to do

LocalH 27 January 2021 03:29

Quote:

Originally Posted by Thalion (Post 1455821)
That sounds promising. I will digitize the VHS tape and send the file to you. What format would be suitable? MPG2 or better something else?

While I'm not Toni, D1-resolution MPEG-2 would probably be the best option. 720x576 at 25fps (704 is also acceptable as they are largely considered equivalent, and the extra 16 pixels won't contain anything meaningful). As long as the vertical frame size is not changed, all fields will be present. As long as the software captures all 576 lines without any deinterlacing, a framerate of 25fps would be what you want (each frame will contain both fields for 50Hz total). From there, something like Avisynth could be used to programmatically separate the fields into individual frames for further decoding.

Toni Wilen 27 January 2021 16:51

Video I got has in my opinion too many mpeg compression artifacts, compression really does not like hard edges of VBS binary data and it causes nearby scanlines to also become horrible blurry.

Non-lossy format is needed. VHS is already lossy, combined with different kind of lossy format that is designed for "normal" video frames makes it even more worse..

Pyromania 28 January 2021 02:56

You could capture the video uncompressed on a Video Toaster [2] card. Those are pretty cheap now. Then hopefully the data would all be there since it’s uncompressed.

fxgogo 28 January 2021 09:19

So Blackmagic Design make an amazing capture card called the Intensity Pro 4K. It will record 10bit 4:4:4 uncompressed video. I used one of these older for animation and work amazingly well. Here is a link: https://www.blackmagicdesign.com/pro...intensitypro4k

Toni Wilen 28 January 2021 09:45

Problem is not capturing, video only contains black and white bars (so it probably is better to capture it in b&w). But because it only contains black and white bars, most (all?) lossy video compression formats don't work very well with it.

Thalion 28 January 2021 13:04

I will try to capture it again with different options. Maybe some usefull output will come out of it.

DerSheriff 28 January 2021 13:48

I remember there was one similar for PCs but it was very slow (slower than other solutions of the time, I mean) and unreliable. So I went for ZIP 100 and 250 :D
And later I discovered it was unreliable too...

indigolemon 28 January 2021 16:33

https://shop.myamigashop.com/product...ommodore-amiga

Seems there's at least one of these for sale!

Thalion 28 January 2021 16:51

Nice find. But 40 USD plus shipping to Europe is a bit much for me just to use this once.

chip 28 January 2021 16:53

Yep, to pay for an hobby isn't a nice thing IMHO :)


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