audio_samples 1.0.5

#[cfg(not(feature = "statistics"))]
pub fn main() {
    eprintln!("Please enable the 'statistics' feature to run this example.");
    std::process::exit(1);
}

#[cfg(feature = "statistics")]
pub fn main() -> audio_samples::AudioSampleResult<()> {
    use audio_samples::{
        AudioSamples, AudioStatistics, AudioTypeConversion, ConvertTo, ToneComponent, sample_rate,
    };
    use ndarray::array;
    use std::time::Duration;
    // At its core, audio_samples aims to provide a way of working with type-safe primitive audio samples.
    // [`AudioSample`]s operate under slightly different conditions than regular primitive types, for example,
    // floats are expected to be normalised to [-1.0, +1.0].

    let i16_val: i16 = i16::MAX;
    let f32_val: f32 = i16_val.convert_to();

    println!("=> Converting i16 to f32...");
    println!("{}_i16 -> {:.2}_f32", i16_val, f32_val);
    println!("=> And back again to i16...");
    let i16_val: i16 = f32_val.convert_to();
    println!("{:.2}_f32 -> {}_i16", f32_val, i16_val);
    println!("\n-----\n");

    // The [`AudioSample`] trait underpins the entire audio system.

    // The more useful side of things though is the AudioSamples<'_, T: AudioSample> struct.
    // This is the core public data structure in the library. It represents a collection of
    // audio samples stored in an ndarray backed structure. It maintains properties such as sample rate automatically.
    // The samples can be mono or multi-channel.
    // The sample_rate macro is used to guarantee that sample rates are valid at compile time.

    let mono_audio =
        AudioSamples::<f32>::new_mono(array![0.1, 0.2, 0.3], sample_rate!(16000)).unwrap();
    let stereo_audio = AudioSamples::<f32>::new_multi_channel(
        array![[0.1, 0.2, 0.3], [0.4, 0.5, 0.6]],
        sample_rate!(44100),
    )
    .unwrap();

    println!("Mono audio: {:#}\n", mono_audio);
    println!("-----\n");
    println!("Stereo audio: {:#}\n", stereo_audio);

    println!("-----\n");

    // AudioSamples can be converted between different sample types easily due to the underlying AudioSampel and ConvertTo traits.
    let stereo_i16 = stereo_audio.to_type::<i16>();
    println!("Converted stereo audio to i16: {:#}\n", stereo_i16);

    // Let's get some more useful audio data
    let sine_wave = audio_samples::sine_wave::<f32>(
        440.0,                                      // Frequency in Hz
        Duration::from_secs(2),                     // Duration
        core::num::NonZeroU32::new(44100).unwrap(), // Sample rate
        1.0,                                        // Amplitude
    );

    println!("Generated sine wave audio: {:#}\n", sine_wave);
    println!("-----\n");

    // Sine waves are useful, but let's get something more practical.
    // Create 440 Hz with harmonics
    let components = [
        ToneComponent::new(440.0, 1.0),   // fundamental
        ToneComponent::new(880.0, 0.5),   // 2nd harmonic
        ToneComponent::new(1320.0, 0.25), // 3rd harmonic
    ];
    let components_slice: &[_] = &components;
    let non_empty = non_empty_slice::NonEmptySlice::from_slice(components_slice).unwrap();
    let audio = audio_samples::compound_tone::<f32>(
        &non_empty,
        Duration::from_secs(2),
        core::num::NonZeroU32::new(44100).unwrap(),
    );

    let (num_channels, samples_per_channel, duration_seconds, sample_rate) = audio.info();
    println!("Compound Tone wave info:");
    println!("Number of channels: {}", num_channels);
    println!("Samples per channel: {}", samples_per_channel);
    println!("Duration (seconds): {:.2}", duration_seconds);
    println!("Sample rate: {} Hz", sample_rate);

    println!("-----\n");

    println!("== Statistics ==");
    println!("Mean: {}", audio.mean());
    println!("RMS: {}", audio.rms());
    println!("Min: {}", audio.min_sample());
    println!("Max: {}", audio.max_sample());
    println!("Variance: {}", audio.variance());
    println!("Standard Deviation: {}", audio.std_dev());
    println!("Peak: {}", audio.peak());
    println!("Zero Crossings: {}", audio.zero_crossings());
    println!("Zero Crossing Rate: {}", audio.zero_crossing_rate());
    #[cfg(feature = "transforms")]
    {
        if let Some(ac) = audio.autocorrelation(audio_samples::nzu!(1)) {
            println!("Autocorrelation (lag 1): {:?}", ac);
        }
    }

    // Create a new 880 Hz tone by shifting the frequency of the original audio
    let components = [
        ToneComponent::new(880.0, 1.0),   // fundamental
        ToneComponent::new(1760.0, 0.5),  // 2nd harmonic
        ToneComponent::new(2640.0, 0.25), // 3rd harmonic
    ];
    let other_audio = audio_samples::compound_tone::<f32>(
        non_empty_slice::NonEmptySlice::from_slice(&components).unwrap(),
        Duration::from_secs(2),
        core::num::NonZeroU32::new(44100).unwrap(),
    );

    println!(
        "Cross-correlation with 880 Hz tone: {:?}",
        audio.cross_correlation(&other_audio, core::num::NonZeroUsize::new(1).unwrap())?
    );
    #[cfg(feature = "transforms")]
    {
        println!("Spectral-centroid: {}", audio.spectral_centroid()?);
        println!("Spectral-rolloff (0.85): {}", audio.spectral_rolloff(0.85)?);
    }
    Ok(())
}