alt.hn

2/23/2026 at 9:57:33 AM

QRTape – Audio Playback from Paper Tape with Computer Vision (2021)

 http://www.theresistornetwork.com/2021/03/qrtape-audio-playback-from-paper-tape.html

by austinallegro

2/23/2026 at 12:11:38 PM

Dolby have been doing this for years for audio on cinema film reels - literally from tiny QR-like codes between the sprocket holes on the filmstrip, with cinema-grade audio quality.

by the-golden-one

2/23/2026 at 2:14:42 PM

Cool project.

Though if you are looking at QR codes for something like this (internal, on paper), strongly consider using data matrix codes. They are more compact, same available error correction codes, and actually have a composition story rather then spaces between them.

Do to how datamatrix codes can be composed, you could probably design a code that both fills the height and does a continuous stream of codes with no horizontal white space between them, just a solid bar as per the spec.

by kardianos

2/23/2026 at 10:01:53 AM

The compression choice is what makes this work. OPUS at 12 kbps is good enough to not embarrass itself — ten years ago you'd have needed a much faster tape speed to get acceptable audio. The paper tape is the aesthetic, the codec is doing the real work.

by enjoykaz

2/23/2026 at 3:15:36 PM

I was thinking, in a world without DRAM, cobalt-infused magnetic tape (like that used for VHS and ferricobalt cassettes) or metal particle tape, digital sound recording would still be possible using 1960s black-and-white VTRs that took ferric oxide tape not dissimilar to those used for analog multitrack recording.

by Paianni

2/23/2026 at 4:07:27 PM

In terms of physical media:

For 1/8" cassette tape, KCS appeared in 1975 but the tape itself was in use 20+ years prior: https://en.wikipedia.org/wiki/Kansas_City_standard

½" consumer tape of Betamax and VHS didn't arrive until the same year.

¼" QIC DC300 appeared ~1972 but was largely inaccessible to hobbyists and home users until around 1995/1996 with QIC-40 and Travan.

There were also home 1/4" reel-to-reel home audio systems from roughly mid '50's onward.

by burnt-resistor

2/23/2026 at 11:15:21 AM

Really like it. For some reason I'd insist on spectrograph instead of qr - artifacts make the medium. The fragile bizarre distortions and loss of the double digitization of analog data - you'd end up with more of an instrument than a format.

Think along these lines https://youtu.be/Z7Zb4rso82M?si=3FYaidCwwVdUhocO

Imagine being able to control where the loss happened in real time with potentiometers

by kristopolous

2/23/2026 at 1:42:32 PM

Has anyone yet made an app that lets you wave your phone around a vinyl record and capture macro video and then play the music through the phone's speaker?

by resters

2/23/2026 at 2:47:06 PM

Years ago I read an article on Slashdot where someone did that with a flatbed scanner. (This was before everyone had a smartphone, and before digital cameras were common.)

Audio quality was poor.

by gwbas1c

2/23/2026 at 4:01:37 PM

This is rad. I love that it's built out of cardboard, but would've accepted LEGO, Tinkertoy (Classic), or Erector Set.

Fantasound was pretty impressive for optical multichannel sound:

https://www.r-type.org/articles/art-299.htm

by burnt-resistor