• towerful@programming.dev
    link
    fedilink
    arrow-up
    10
    ·
    edit-2
    1 year ago

    They go on to deduce it’s an off-by-one error in the time domain.
    So instead of 0-127 it’s processing 0-126 samples (a classing i < 127 instead of i <= 127 in a for loop)

    https://social.treehouse.systems/@marcan/111160552044972689

    The train of thought was:

    • The aliasing is every 375 Hz.
    • 48000 / 375 = 128 so this is some fourier thing with a block size 128???
    • Wait no, this could be time domain, aliasing like that is what you get when you upsample without lowpassing.
    • Specifically, when you upsample with zero-sample padding (standard), that is, when one sample out of 128 has the low frequency content.
    • So this is like taking the average of a 128-sample block and adding it to just one sample?
    • Wait, isn’t that almost equivalent to zeroing out one sample?

    numpy time

    fs, signal = wavfile.read("sweep.wav")
    signal[::128] = 0
    wavfile.write("lol.wav", fs, signal)
    

    And the rest is history.

    Edit:
    Stupid less-than symbol getting html-coded

  • Ocean@lemmy.blahaj.zone
    link
    fedilink
    English
    arrow-up
    8
    ·
    1 year ago

    I get that this is a bug, but it kinda sucks that people feel it’s all right to act this way. Software is hard and unless you’re using a language with zero-overhead iteration you’re probably writing your drivers in C and iterating with a for-loop like our ancestors did. Off by one errors are stupidly common and everyone is human.

    I mean, fuck mega corporations. This is still cringeworthy.

    That being said, it’s going to be fun to see quality differences in these operating systems in a few years because, as far as I know, Apple would rather force Swift into the systems-level language space than adopt a memory-safe language today.

    Meanwhile Microsoft, Google, and Amazon, etc are all investing heavily in Rust by integrating it into their platforms.