fix: resample pcm stream chunks for livekit

cai

2026-07-06 e83f248c676f1ed56e5c42d16da9fba395285fe3

 src/main.rs

@@ -1377,6 +1377,20 @@
                );
                return Ok(0);
            }
            Err(error) if state.first_audio_frame_written => {
                warn!(
                    call_id = %call_id,
                    trace_id = %trace_id,
                    turn_id = %turn.turn_id,
                    chunk_seq = audio_chunk.chunk_seq.unwrap_or_default(),
                    format = %format,
                    buffered_bytes = state.encoded_audio_buffer.len(),
                    error = %safe_error(&error.to_string()),
                    "runtime helper stream_audio_final_chunk_decode_ignored"
                );
                state.encoded_audio_buffer.clear();
                return Ok(0);
            }
            Err(error) => return Err(error).context("failed to decode final stream audio chunk"),
        }
    } else {
@@ -1451,39 +1465,13 @@
    sample_rate: u32,
    channels: u32,
) -> Result<Vec<PcmFrame>> {
    if sample_rate != TARGET_SAMPLE_RATE_HZ || channels != u32::from(TARGET_NUM_CHANNELS) {
        return Err(anyhow!(
            "unsupported pcm_s16le stream format: sample_rate={}, channels={}",
            sample_rate,
            channels
        ));
    }
    if payload.len() % 2 != 0 {
        return Err(anyhow!("pcm_s16le payload has odd byte length"));
    }
    let samples: Vec<i16> = payload
        .chunks_exact(2)
        .map(|chunk| i16::from_le_bytes([chunk[0], chunk[1]]))
        .collect();
    if samples.is_empty() {
        return Ok(Vec::new());
    }
    let samples_per_channel = (sample_rate / 50).max(1);
    let frame_sample_count = samples_per_channel as usize * channels as usize;
    let mut frames = Vec::new();
    for chunk in samples.chunks(frame_sample_count) {
        let chunk_samples_per_channel = (chunk.len() / channels as usize) as u32;
        if chunk_samples_per_channel == 0 {
            continue;
        }
        frames.push(PcmFrame::new(
            chunk.to_vec(),
            sample_rate,
            channels,
            chunk_samples_per_channel,
        ));
    }
    Ok(frames)
    audio::pcm_s16le_bytes_to_frames(
        payload,
        sample_rate,
        channels,
        TARGET_SAMPLE_RATE_HZ,
        TARGET_NUM_CHANNELS,
    )
}

fn trim_ascii_whitespace(value: &[u8]) -> &[u8] {