VHS Video Archival

I gained a fascination for "bad" old video tapes from watching Red Letter Media's "Best of the Worst" and related series, which congealed into wanting to find my own "bad" tapes and archiving them. Specifically, I wanted to find these closer to home, that is germany, and capture the flavour of junk that was present here. The conventional way of archiving video tapes is to acquire a tape machine in a good state, a high quality video capture card, a good monitor, and some more gear like timebase correctors. This kind of setup can quickly get into an obscene price range, exacerbated by grifters. You are also possibly saddling yourself with quite some mechanical and electrical maintenance labor.

Another approach (mostly) skips using this aging, expensive premium equipment. Instead, the video signal is captured as close to the magnetic tape as possible. For this purpose signal tap lines are installed in any *mechanically* working VCR. The unprocessed information from the tape is amplified, digitized, and then decoded in software. This produces high quality transfers of analog video tapes, at a relatively low price. There is multiple approaches to the digitization process of the magnetic information, which range in terms of cost quite a lot. The principle is the same, and if you ask me, the quality mostly is as well.

Considering I am actively looking for junk to transfer, I am moving at the lower end of the spectrum. This process is also possible for many other analog video formats. You can find much information on this project here. You can also find everything I have transferred so far on my YouTube channel.

I have had very little experience working with electronics before, and none with analog video. This project taught me a lot, such as using an oscilloscope, modding electronic hardware, made be better at soldering and working with a Linux computer. It also reduced a lot of my fear of working with electronics, something which I tended to consider extremely hard, from previous experiences of breaking everything I touched (haha)... Definetly one of those hobbies where I sometimes start yapping intensely at people without explaining enough about this obscure topic.

To digitize the signal from the tape this approach repurposes two PCI video grabber cards ("CX-Cards"). These are meant, for example, to feed CCTV cameras into a PC for monitoring and recording. A custom driver was written to make these produce a stream of raw sample data, turning them into high speed analog-digital-converters (ADC). This sample data represents the magnetic information on the tape and is decoded. One card is used for each of the two streams of data that can be decoded from a single VHS tape. One captures the video signal, the other the stereo HiFi-Audio.

To improve the quality of the sample data a custom clock generator replaces the on-board oscillator, forcing the card to sample at a much higher frequency than it's default. This cool setup unfortunately introduces a lot of jank and opportunity for error. The clock signal I managed to generate with it is of miserable quality and suffers even more in transmission to the cards. I suspect the failure of the setup (I write about it further down) is due to this. Maybe. I couldnt improve it, in any case, but it was good enough to get the first captures done, especially since I was only capturing on a single CX-Card yet.

I got this one from my grandparents. Modding this one was very successful, and I made most of my transfers so far on it. It was relatively unused and the tape mechanism was still very stable for that reason. The issue with this one was that it was from the late 80s and did not yet have high-quality stereo audio, as basically all later machines have. An upgrade was needed...

This is a really cool machine. It was made for medical use, featuring very stable still frame display and audio dubbing to create reports from medical imaging. It also had HiFi audio, playback for multiple tape formats (NTSC, SECAM), among many other adjustable goodies.

Unfortunately it has also seen a lot of use and abuse. It clearly was used by a smoker for most of it's life, and played a LOT of tapes without maintenance. It was not really well adjusted and I could only make so much improvement to that with simple tools (screwdriver). I also had to fixi the gear loading mechanism before use, though that was mostly fun. The encoder wheel that tells the machine what state it currently is in (No tape, loading, loaded, playing, paused, ...) was oxidized and confusing it by not giving proper feedback on those states.

Side note: If you take apart a geared mechanism, take very good note of the timing of the gears! Mark everything and take many photos to remember how the gears have to be rotated in relation to each other in the state you took it apart in. I removed the faulty tape loading mechanism to repair it and it took DAYS of work to figure the gears out again after that...

It generally worked alright, but I ran into issues with the capturing setup I had built at this point. For an unknown reason, connecting both CX-Cards to my PC causes one of the digitized captures to distort heavily and become unsuable. So while I had a working stereo machine at this point, I still couldn't fully decode video plus HiFi audio. Instead I had to rely on capturing the analog stereo speaker output from the tape machine. This meant more noise and more post-production effort to sync up audio and video. An upgrade was needed...

This is more or less a very boiled down version of the first capturing setup. Instead of the CX-Cards it uses off the shelf ADCs (as in meant-to-be ADCs), which should be more reliable. A really interesting part of it is the use of a HDMI connection, not to transfer video to the capturing PC, but to transfer the raw capture data, by use of a modified driver (HSDOAH). This enables the Raspberry Pi Pico used on it to transfer very high data rates (without the use of, say USB3, which the Pico doesn't have!). This stream is captured by a cheap HDMI-to-USB capture card plugged into the PC.

As time of writing I am still waiting on parts to build this thing.

This thing is a dirt cheap production and probably a rebrand. A duo VCR+DVD player meant for doing cheap and bad transfers of VHS tapes straight to DVD. These usually feature very poor digitization circuitry and even worse compression on the resulting digital video. (I should try it some time...)

The upside is that by the late 2000s when this was made, video tape drives have become incredibly simple and small. This thing is almost empty, meaning I can easily install mods into the case. Also, this drive suffers neither from heavy use nor old age. The tape drive itself is a module that just slots into the mainboard of the machine from the top. Incredibly cool! Another upside of modern machines is that they have lots of automatic control circuitry to adjust themselves for optimal playback (e.g. tracking). So this was, while it is pretty uncool, a big upgrade from the last one.

Modding this was straightforward and I knew what I was doing at this point. I quickly found my tap spots for Video-, HiFi-, and Headswitch-Signals and 12V power for the amplifier, even though there is no electrical documentation for this machine. The back had some convenient unused holes that I routed the BNC jacks through without any drilling.

A special feature that was suggested to me is an adjustable gain for the initial amplification. This is done by adding variable resistors to the amplifier board. I have seen a lot of range in the signal strength of my tapes so far, so this should enable better transfers of those with especially weak and strong signal.

As time of writing I am still waiting on parts to build the amplifier that will be installed in here. You can see my signal taps in the bottom right of the photo. Two black wires are coming from the inside of the machine, carrying video and audio. They would be connected to the input of this amplifier. The amplified signals then exit out the back, at the two open BNC connectors with salmon colored wires that stick out in the same area.