neteq 0.8.3

NetEQ-inspired adaptive jitter buffer for audio decoding
Documentation 
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/*
 * Copyright 2025 Security Union LLC
 *
 * Licensed under either of
 *
 * * Apache License, Version 2.0
 *   (http://www.apache.org/licenses/LICENSE-2.0)
 * * MIT license
 *   (http://opensource.org/licenses/MIT)
 *
 * at your option.
 *
 * Unless you explicitly state otherwise, any contribution intentionally
 * submitted for inclusion in the work by you, as defined in the Apache-2.0
 * license, shall be dual licensed as above, without any additional terms or
 * conditions.
 */

use super::AudioDecoder;
use crate::Result;

// Native libopus decoder for native targets
#[cfg(not(target_arch = "wasm32"))]
use opus::{Channels, Decoder as OpusInner};

#[cfg(not(target_arch = "wasm32"))]
/// Wrapper around libopus via the `opus` crate (native targets).
#[derive(Debug)]
pub struct NativeOpusDecoder {
    inner: OpusInner,
    sample_rate: u32,
    channels: u8,
}

#[cfg(not(target_arch = "wasm32"))]
impl NativeOpusDecoder {
    /// Create a new synchronous native Opus decoder
    pub fn new(sample_rate: u32, channels: u8) -> Result<Self> {
        let ch_enum = match channels {
            1 => Channels::Mono,
            2 => Channels::Stereo,
            _ => return Err(crate::NetEqError::InvalidChannelCount(channels)),
        };
        let inner = OpusInner::new(sample_rate, ch_enum)
            .map_err(|e| crate::NetEqError::DecoderError(format!("Opus init: {e}")))?;
        Ok(Self {
            inner,
            sample_rate,
            channels,
        })
    }

    #[allow(dead_code)]
    pub async fn new_async(sample_rate: u32, channels: u8) -> Result<Self> {
        Self::new(sample_rate, channels)
    }
}

#[cfg(not(target_arch = "wasm32"))]
impl AudioDecoder for NativeOpusDecoder {
    fn sample_rate(&self) -> u32 {
        self.sample_rate
    }
    fn channels(&self) -> u8 {
        self.channels
    }

    fn decode(&mut self, encoded: &[u8]) -> Result<Vec<f32>> {
        let max_samples = (self.sample_rate as usize * 120 / 1000) * self.channels as usize;
        let mut buf = vec![0.0f32; max_samples];
        let decoded_samples = self
            .inner
            .decode_float(encoded, &mut buf, false)
            .map_err(|e| crate::NetEqError::DecoderError(format!("Opus decode: {e}")))?;
        buf.truncate(decoded_samples * self.channels as usize);
        Ok(buf)
    }
}

// -----------------------------------------------------------------------------
// WebCodecs AudioDecoder (web)
// -----------------------------------------------------------------------------

// WebCodecs decoder temporarily disabled - using Safari decoder for all web targets
#[cfg(target_arch = "wasm32")]
#[allow(dead_code)]
/// WebCodecs AudioDecoder wrapper for browsers that support it (Chrome, Firefox)
pub struct NativeOpusDecoder {
    sample_rate: u32,
    channels: u8,
}

#[cfg(target_arch = "wasm32")]
impl NativeOpusDecoder {
    #[allow(dead_code)]
    pub async fn new(sample_rate: u32, channels: u8) -> Result<Self> {
        // WebCodecs implementation disabled for now
        Ok(Self {
            sample_rate,
            channels,
        })
    }
}

#[cfg(target_arch = "wasm32")]
impl AudioDecoder for NativeOpusDecoder {
    fn sample_rate(&self) -> u32 {
        self.sample_rate
    }

    fn channels(&self) -> u8 {
        self.channels
    }

    fn decode(&mut self, _encoded: &[u8]) -> Result<Vec<f32>> {
        // WebCodecs implementation disabled - return silence
        let samples = (self.sample_rate as f32 * 0.02) as usize * self.channels as usize;
        Ok(vec![0.0; samples])
    }
}