Function encode_wav_bytes

cake-core/src/utils/wav.rs:11–41

Encode PCM f32 samples as WAV bytes (16-bit PCM, mono).

(samples: &[f32], sample_rate: u32)

/// Encode PCM f32 samples as WAV bytes (16-bit PCM, mono).
pub fn encode_wav_bytes(samples: &[f32], sample_rate: u32) -> Vec<u8> {
    let num_samples = samples.len() as u32;
    let byte_rate = sample_rate * 2; // 16-bit mono = 2 bytes per sample
    let data_size = num_samples * 2;
    let file_size = 36 + data_size;

    let mut buf = Vec::with_capacity(file_size as usize + 8);
    // RIFF header
    buf.extend_from_slice(b"RIFF");
    buf.extend_from_slice(&file_size.to_le_bytes());
    buf.extend_from_slice(b"WAVE");
    // fmt chunk
    buf.extend_from_slice(b"fmt ");
    buf.extend_from_slice(&16u32.to_le_bytes()); // chunk size
    buf.extend_from_slice(&1u16.to_le_bytes()); // PCM format
    buf.extend_from_slice(&1u16.to_le_bytes()); // mono
    buf.extend_from_slice(&sample_rate.to_le_bytes());
    buf.extend_from_slice(&byte_rate.to_le_bytes());
    buf.extend_from_slice(&2u16.to_le_bytes()); // block align
    buf.extend_from_slice(&16u16.to_le_bytes()); // bits per sample
    // data chunk
    buf.extend_from_slice(b"data");
    buf.extend_from_slice(&data_size.to_le_bytes());
    // Convert all samples to i16 bytes in one pass — single extend_from_slice
    let sample_bytes: Vec<u8> = samples
        .iter()
        .flat_map(|&s| ((s.clamp(-1.0, 1.0) * 32767.0) as i16).to_le_bytes())
        .collect();
    buf.extend_from_slice(&sample_bytes);
    buf
}

/// Save PCM f32 samples as a WAV file (16-bit PCM, mono).
pub fn save_wav(samples: &[f32], path: &Path, sample_rate: u32) -> Result<()> {