audio-visualizer 0.5.0

Simple audio visualization library which is especially useful for developers to visually check audio samples, e.g. by waveform or spectrum. (So far) this library is not capable of doing nice visualizations for end users.
Documentation 
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use std::fs::File;
use std::path::Path;
use symphonia::core::audio::{AudioBuffer, Signal};
use symphonia::core::io::MediaSourceStream;
use symphonia::core::probe::Hint;
use symphonia::default::{get_codecs, get_probe};

pub mod sine;

/// Directory with test samples (e.g. mp3) can be found here.
pub const TEST_SAMPLES_DIR: &str = "test/samples";
/// If tests create files, they should be stored here.
pub const TEST_OUT_DIR: &str = "target/test_out";

/// Returns an MP3 as decoded i16 samples and with LRLR interleavement.
pub fn decode_mp3(file: &Path) -> Vec<i16> {
    let file = File::open(file).unwrap();
    let mss = MediaSourceStream::new(Box::new(file), Default::default());
    let probed = get_probe()
        .format(
            &Hint::default(),
            mss,
            &Default::default(),
            &Default::default(),
        )
        .unwrap();
    let mut format_reader = probed.format;
    let track = format_reader.tracks().first().unwrap();
    let mut decoder = get_codecs()
        .make(&track.codec_params, &Default::default())
        .unwrap();

    let mut audio_data_lrlr = Vec::new();
    while let Ok(packet) = format_reader.next_packet() {
        if let Ok(audio_buf_ref) = decoder.decode(&packet) {
            let audio_spec = audio_buf_ref.spec();
            let mut audio_buf_i16 =
                AudioBuffer::<i16>::new(audio_buf_ref.frames() as u64, *audio_spec);
            audio_buf_ref.convert(&mut audio_buf_i16);

            match audio_spec.channels.count() {
                2 => {
                    let iter = audio_buf_i16
                        .chan(0)
                        .iter()
                        .zip(audio_buf_i16.chan(1))
                        // LRLR interleavment
                        .flat_map(|(&l, &r)| [l, r]);
                    //.map(|(&l, &r)| ((l as i32 + r as i32) / 2) as i16);
                    audio_data_lrlr.extend(iter);
                }
                n => panic!("Unsupported amount of channels: {n}"),
            }
        }
    }
    audio_data_lrlr
}