Function waveform 

pub fn waveform(
    file: &Path,
    buckets: usize,
    ffmpeg: Option<&Path>,
) -> Result<Vec<f32>, ExportError>

Peak envelope of an audio file for the editor’s waveform: buckets values in 0..=1, decoded with ffmpeg at 8 kHz mono.

Errors

If ffmpeg is missing or cannot decode the file.