Audio waveform lane — ED.10

For decades the picture editor cut blind to sound, then threaded a separate magnetic track onto the flatbed's soundhead so picture and audio ran in sync — and you cut on what you could hear. The waveform is that mag track made visible: you find the breath before a sentence, the click of a button, the silence to trim, all by eye. You cannot splice on a sound you cannot see.

downsample_peaks turns a sea of samples into one min/max pair per horizontal bucket — the peak envelope. Drawing every sample is both impossible (millions of them) and pointless (the screen has a few hundred pixels); the envelope is exactly what the eye reads. The AudioWaveform lane draws those buckets beneath the video track, aligned to the same timeline.

flowchart LR
  S["44.1k samples/s"] -- "min/max per bucket" --> E["~N envelope buckets"]
  E --> BARS["waveform bars under the video lane"]