refactor: 使用 UDP 传输音频流

apps/hello/src/audio/codec.rs

@@ -1,6 +1,6 @@
-use opus::{Encoder, Decoder, Application, Bitrate, Channels};
-use anyhow::{Result, Context};
 use crate::config::AudioConfig;
+use anyhow::{Context, Result};
+use opus::{Application, Bitrate, Channels, Decoder, Encoder};
 
 pub struct OpusCodec {
     encoder: Encoder,
@@ -9,23 +9,37 @@ pub struct OpusCodec {
 
 impl OpusCodec {
     pub fn new(config: &AudioConfig) -> Result<Self> {
-        let channels = if config.channels == 1 { Channels::Mono } else { Channels::Stereo };
+        let channels = if config.channels == 1 {
+            Channels::Mono
+        } else {
+            Channels::Stereo
+        };
         let mut encoder = Encoder::new(config.sample_rate, channels, Application::Audio)
             .context("Failed to create Opus encoder")?;
         encoder.set_bitrate(Bitrate::Bits(config.bitrate))?;
 
-        let decoder = Decoder::new(config.sample_rate, channels)
-            .context("Failed to create Opus decoder")?;
+        let decoder =
+            Decoder::new(config.sample_rate, channels).context("Failed to create Opus decoder")?;
 
         Ok(Self { encoder, decoder })
     }
 
     pub fn encode(&mut self, pcm: &[i16], out: &mut [u8]) -> Result<usize> {
-        self.encoder.encode(pcm, out).context("Opus encoding failed")
+        self.encoder
+            .encode(pcm, out)
+            .context("Opus encoding failed")
     }
 
     pub fn decode(&mut self, opus: &[u8], out: &mut [i16]) -> Result<usize> {
-        self.decoder.decode(opus, out, false).context("Opus decoding failed")
+        self.decoder
+            .decode(opus, out, false)
+            .context("Opus decoding failed")
+    }
+
+    // Packet Loss Concealment
+    pub fn decode_loss(&mut self, out: &mut [i16]) -> Result<usize> {
+        // Fallback to silence as opus crate 0.3 doesn't expose safe PLC
+        out.fill(0);
+        Ok(out.len())
     }
 }
-