saving videotape signals directly



   ..what is all this about anyway?
when fate made it so i ended up with a free VCR/DVD combo player around the same time i received a completely undocumented program from a university, i searched high and low to figure out what the best way to back up the contents of this and any other video tapes i came across.

at the time, many of the results and cited sources in videos pointed to decades-old forum websites that insisted on spending $4000 or more on very specific pieces of video equipment (which i later learned did not even do their jobs very well...) even before discovering a different method, this just felt wrong to me. why spend so much money on such a setup, being dependent on so many external factors with minimal/no user control?

enter “vhs-decode”, a project that revolves around working off of the raw signals directly from videotape sources. in a sense it’s like a software VCR, and most crucially, spending thousands of dollars on hyper-specific VCR models, timebase correctors, “power conditioners” and so on are not necessary! with some soldering knowledge, it doesn’t take much to produce results that rival pricey options for a fraction of the cost. furthermore, once you have the raw signal digitized, you can decode that as many times as you like without causing further wear to the original tape source!

since making this page, i have also expanded this same software decoding system to betamax and u-matic VTR systems with similar success.

examples


a deep dive into how i digitized a set of moldy, warped, and flaking-away U-matic tapes that once belonged to the New York Institute of Technology’s Computer Graphics Lab, now shown in a documentary about their cancelled film project named “The Works”.

images and other info


a spectrogram view of the raw, FM + QAM video signal at the start of a VHS tape. the modified capture hardware i use effectively works like a very fast sound recorder which samples at 40 MHz (yes, MHz - not KHz!), where vhs-decode then decodes the raw signal into individual frames, and finally a video file.
a single frame of the black and white (luma) channel from a VHS off-air recording, showing the vertical sync pulse, vertical blanking area and full active picture. as of writing this, no consumer-available analog capture card can currently digitize this extra data beyond the active picture. of note in this example is the extra data sitting in the VBI - that’s Teletext data from the long since defunct Electra service!
©2026 isiah f