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Simulate cassette tape audio profiles using FFmpeg

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Re: Simulate cassette tape audio profiles using FFmpeg

#41
post #27

Would be interested to see something like this to simulate VHS effects

That might be of interest: https://ntsc.rs/

"ntsc-rs is written in Rust, and is multithreaded and SIMD-accelerated."

This made me lol. I know so few video editor types that would use a plugin like this that would know what Rust was to be "impressed" by this bit of PR.

Re: Simulate cassette tape audio profiles using FFmpeg

#43
post #10

Has anyone come across a Dolby B (or similar) encode / decode program? I've been wanting to experiment with quantizing Dolby (or similar) encoded audio to 8 bits, and then unencoding to see how well it can sound.

Dolby was just pre-emphasis of the higher frequencies before they were written to the tape.

It will sound the same with 8 bits. 8bit quantization will give you 48dB dynamic range (best case). Call it 36dB practical, around the same as an average cassette tape.

Re: Simulate cassette tape audio profiles using FFmpeg

#45
post #3

What is "wow"?

Half of wow and flutter. The tape speed wasn't perfectly constant, so the pitch wobbled. Wow was slow speed variations (under 4Hz). Flutter was quicker warbles. Both were caused mechanically. The rubber wheel - pinch roller - that moved the tape might not be perfectly circular, the motor that pulled the reels might be uneven, and the tape case sometimes pressed on the tape reels causing variable friction. Analog medi…

> Analog media really were a bit crap. I get the creative distortion idea, but even so - ewww.

On digital music production some randomisation (sometimes called swing in sequencers) is often added so the notes aren't played exactly at the right time.

Perfection often sounds a bit dull the same way seeing a perfectly symmetrical human face feels weird.

Re: Simulate cassette tape audio profiles using FFmpeg

#46

How would one go about determining what effect to add for each cassette type? I don't know much about cassettes, I'm curious if this was something that could be done by ear or if these are commonly held opinions about the sound of each tape. Again knowing nothing about tape, if I were tasked with this I would probably try to record the same audio to each of the tapes and then compare it with the original.

I was too young to do much with this information, but I not-so-vaguely recall my father cared deeply about getting metal-tapes. Not the music, but the material. I don't know if they lasted longer or sounded better (and now I would suspect: maybe have a sound profile he liked, rather than have high fidelity), but it was important to him.

Re: Simulate cassette tape audio profiles using FFmpeg

#47
Aha, there are later type TDK D90s, I wonder if they'll add mid-80s ones? Either way it may be possible to test an idea I've had for a long time that borders on "low stakes conspiracy theories".

All those albums you loved in the mid-to-late 80s, if you're about my age, like Appetite for Destruction, Master of Puppets, Somewhere in Time, First and Last and Always, Fear of a Black Planet, or even Pretty Hate Machine - these were all mastered not to sound best in a pristine recording but to sound best when pirated off your mate's big brother's CD of it onto a TDK D90 that had been rattling around in your schoolbag for months.

Because these are just some of the pirated tapes I have on hand from when I was 14 or 15 or so, and they definitely sound better than the bought-and-paid-for CDs I eventually bought once I had money to spend on such things.

Re: Simulate cassette tape audio profiles using FFmpeg

#49
post #3

What is "wow"?

Half of wow and flutter. The tape speed wasn't perfectly constant, so the pitch wobbled. Wow was slow speed variations (under 4Hz). Flutter was quicker warbles. Both were caused mechanically. The rubber wheel - pinch roller - that moved the tape might not be perfectly circular, the motor that pulled the reels might be uneven, and the tape case sometimes pressed on the tape reels causing variable friction. Analog medi…

> I'm so happy these kinds of imperfections are optional now, and not baked into music distribution systems as an expected flaw.

99.9% of the stuff on the music distribution systems we have now is lossily compressed with perceptual coding. That introduces a shitload more artifacts than any analogue wobble.

(I wonder if people 50 years from now will have special algorithms to introduce that coveted "authentic mp3 artifact vibe of the vintage 2010's".)

Re: Simulate cassette tape audio profiles using FFmpeg

#50
post #11

To which analog gain would 0 dBFS be mapped?

i don’t think any dynamic range manipulation is being done, beyond the slight variations as a consequence of the other processing. generally 0dBVU is mapped to -18dBFS with VU style RMS metering being used on the digital side as well. but that isn’t some kind of physical translation, it’s rather arbitrary and more a convention.

So no tape saturation? That would be to me one of the most interesting bits of the tape sound, at least for musical applications.
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