Found these two interesting articles on U-matic and CVC video tape archiving. They are NASA level stuff. I wonder if anyone did a similar thing for VHS, etc.
Found this interesting website on video archival. https://www.iasa-web.org/tc06/guidelines-preservation-video-recordings
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Last edited by KarMa; 6th Mar 2019 at 09:41.
Ran into a few U-matic machines in a public TV station with donated equipment. They worked sometimes.
Used mostly for commercials or announcements.
A bit earlier we had a 1/4" B+W reel to reel video recorder in our electronics class. Poor quality video and prone to break the tapes and make a mess.
It operated at close to FF or RW speeds when recording and playback. Might have been an Ampex.
Doesn't seem like magnetic tape has much of a future these days. But's it good to try to preserve/convert the old tapes for the next generation.
As the doc says, and I can attest, it is much easier with NTSC machines, as there is a simple adapter that converts the "Dub" (Y/C) din connector to standard S-Video. Used it all the time with U-Matic and Hi-8 decks. Didn't know PAL decks needed a workaround, though.
I'm pretty sure there's a newer thread about this at digitalfaq.com, but this thread talks about an ongoing project to capture the Laserdisc signal before any processing (software and hardware) to video output. And there's a like to someone else trying to do the same thing with VHS: http://www.digitalfaq.com/forum/video-capture/8586-archiving-laserdiscs-player.html
Edit: Found the newer thread: http://www.digitalfaq.com/forum/video-capture/9432-decoding-vhs-rf.html#post59285
Well with LD, it's stored in composite so there isn't much to be done besides just capturing the composite and finding the best comb filter you can to separate the Y and C.
IMHO should be possible to combine servo signal with RF FM head signal thus same ADC can be used - ideal case for simultaneous sampling.
Answering to lordsmurf:
Why it will be beneficial? As it will remove serious limitations of VCR mechanics and electronics - firstly in digital domain information using frequency division (i.e. different part of spectrum are used to store different type of information - for VCR this is Y and C but also can be FM HQ audio) can be precisely extracted, secondly it can be accurately demodulated as video signal bandwidth is comparable with FM video signal bandwidth - quite difficult case for analog electronics where demodulation is always trade of between time (in this case it must be real time) and component accuracy/tolerance. Also tape speed changes (unwanted but present) can be compensated in FM domain before demodulation (especially with servo signal present in capture this open way to restore potentially unplayable tapes - there is thread with such issue active now). Simply we can operate on FM signal in different way than on demodulated video samples.
But i agree - this is complex area, lot of human work is required and overall benefits may be unjustified - same as in other areas - some people consider H.264 movie compressed with CRF=26 or even 28 as good/very good where other people consider anything higher than CRF=18 as abomination.
Everything depends what is your gaol - digital preservation or just content consumption.