feat: 动态链接到 opus 和 alsa 基础库，完成音频录制播放和编解码

2025-12-31 22:53:33 +08:00
parent c521e274e9
commit fba40393c2
11 changed files with 431 additions and 46 deletions
@@ -0,0 +1,31 @@
+use opus::{Encoder, Decoder, Application, Bitrate, Channels};
+use anyhow::{Result, Context};
+use crate::config::AudioConfig;
+
+pub struct OpusCodec {
+    encoder: Encoder,
+    decoder: Decoder,
+}
+
+impl OpusCodec {
+    pub fn new(config: &AudioConfig) -> Result<Self> {
+        let channels = if config.channels == 1 { Channels::Mono } else { Channels::Stereo };
+        let mut encoder = Encoder::new(config.sample_rate, channels, Application::Voip)
+            .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")?;
+
+        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")
+    }
+
+    pub fn decode(&mut self, opus: &[u8], out: &mut [i16]) -> Result<usize> {
+        self.decoder.decode(opus, out, false).context("Opus decoding failed")
+    }
+}
+
@@ -0,0 +1,8 @@
+pub mod recorder;
+pub mod player;
+pub mod codec;
+
+pub use recorder::AudioRecorder;
+pub use player::AudioPlayer;
+pub use codec::OpusCodec;
+
@@ -0,0 +1,54 @@
+use crate::config::AudioConfig;
+use alsa::pcm::{Access, Format, HwParams, PCM};
+use alsa::Direction;
+use anyhow::{Context, Result};
+
+pub struct AudioPlayer {
+    pcm: PCM,
+}
+
+impl AudioPlayer {
+    pub fn new(config: &AudioConfig) -> Result<Self> {
+        let pcm = PCM::new(&config.playback_device, Direction::Playback, false)
+            .context("Failed to open playback PCM device")?;
+
+        setup_pcm(&pcm, config.sample_rate, config.channels)?;
+        Ok(Self { pcm })
+    }
+
+    pub fn write(&self, buffer: &[i16]) -> Result<usize> {
+        let res = self.pcm.io_i16()?.writei(buffer);
+
+        match res {
+            Ok(written) => Ok(written),
+            Err(e) => {
+                // Buffer Underrun，即播放缓冲区的数据被耗尽，导致音频流中断
+                if e.errno() == 32 {
+                    // 恢复音频流状态
+                    self.pcm.prepare()?;
+                    // 重新获取 IO 对象并尝试写入数据
+                    self.pcm
+                        .io_i16()?
+                        .writei(buffer)
+                        .context("Failed to write to playback device after recovery")
+                } else {
+                    Err(e).context("Failed to write to playback device")
+                }
+            }
+        }
+    }
+}
+
+fn setup_pcm(pcm: &PCM, sample_rate: u32, channels: u16) -> Result<()> {
+    let hwp = HwParams::any(pcm).context("Failed to get HwParams")?;
+    hwp.set_access(Access::RWInterleaved)?;
+    hwp.set_format(Format::s16())?;
+    hwp.set_rate(sample_rate, alsa::ValueOr::Nearest)?;
+    hwp.set_channels(channels as u32)?;
+    pcm.hw_params(&hwp).context("Failed to set HwParams")?;
+
+    let swp = pcm.sw_params_current()?;
+    pcm.sw_params(&swp)?;
+    pcm.prepare()?;
+    Ok(())
+}
@@ -0,0 +1,37 @@
+use alsa::pcm::{PCM, HwParams, Format, Access};
+use alsa::Direction;
+use anyhow::{Result, Context};
+use crate::config::AudioConfig;
+
+pub struct AudioRecorder {
+    pcm: PCM,
+}
+
+impl AudioRecorder {
+    pub fn new(config: &AudioConfig) -> Result<Self> {
+        let pcm = PCM::new(&config.capture_device, Direction::Capture, false)
+            .context("Failed to open capture PCM device")?;
+        
+        setup_pcm(&pcm, config.sample_rate, config.channels)?;
+        Ok(Self { pcm })
+    }
+
+    pub fn read(&self, buffer: &mut [i16]) -> Result<usize> {
+        self.pcm.io_i16()?.readi(buffer).context("Failed to read from capture device")
+    }
+}
+
+fn setup_pcm(pcm: &PCM, sample_rate: u32, channels: u16) -> Result<()> {
+    let hwp = HwParams::any(pcm).context("Failed to get HwParams")?;
+    hwp.set_access(Access::RWInterleaved)?;
+    hwp.set_format(Format::s16())?;
+    hwp.set_rate(sample_rate, alsa::ValueOr::Nearest)?;
+    hwp.set_channels(channels as u32)?;
+    pcm.hw_params(&hwp).context("Failed to set HwParams")?;
+    
+    let swp = pcm.sw_params_current()?;
+    pcm.sw_params(&swp)?;
+    pcm.prepare()?;
+    Ok(())
+}
+
@@ -0,0 +1,25 @@
+pub struct AudioConfig {
+    pub capture_device: String,
+    pub playback_device: String,
+    pub sample_rate: u32,
+    pub channels: u16,
+    pub frame_size: usize,
+    pub bitrate: i32,
+}
+
+impl Default for AudioConfig {
+    fn default() -> Self {
+        Self {
+            // 根据 apps/runtime/squashfs-root/etc/asound.conf 分析：
+            // 录音设备对应 pcm.Capture -> hw:0,3 (S32_LE, 48000Hz)
+            // 播放设备对应 pcm.dmixer -> hw:0,2 (S16_LE, 48000Hz)
+            // 使用 "default" 或 "plug" 设备可以由 ALSA 自动处理采样率和格式转换
+            capture_device: "plug:Capture".to_string(),
+            playback_device: "default".to_string(),
+            sample_rate: 16000, // Opus 常用 16k，ALSA plug 会自动从 48k 转换
+            channels: 1,
+            frame_size: 320, // 20ms at 16kHz
+            bitrate: 16000,
+        }
+    }
+}
@@ -1,9 +1,63 @@
-fn main() {
-    println!("Hello from OpenWrt (ARMhf)!");
-    println!("System information (via /proc/version):");
-    if let Ok(version) = std::fs::read_to_string("/proc/version") {
-        println!("{}", version);
-    } else {
-        println!("Could not read /proc/version (running in simulation?)");
+mod audio;
+mod config;
+
+use crate::audio::{AudioPlayer, AudioRecorder, OpusCodec};
+use crate::config::AudioConfig;
+use anyhow::Result;
+use std::collections::VecDeque;
+use std::time::{Duration, Instant};
+
+fn main() -> Result<()> {
+    let config = AudioConfig::default();
+    println!("Starting Audio Modular Demo with 1s delay");
+    println!(
+        "Config: capture={}, playback={}, rate={}, channels={}, frame_size={}",
+        config.capture_device,
+        config.playback_device,
+        config.sample_rate,
+        config.channels,
+        config.frame_size
+    );
+
+    let recorder = AudioRecorder::new(&config)?;
+    let player = AudioPlayer::new(&config)?;
+    let mut codec = OpusCodec::new(&config)?;
+
+    // 使用队列存储编码后的 Opus 数据块及录制时间
+    let mut delay_queue: VecDeque<(Instant, Vec<u8>)> = VecDeque::new();
+    let delay_duration = Duration::from_secs(1);
+
+    let mut pcm_in = vec![0i16; config.frame_size * config.channels as usize];
+    let mut opus_buf = vec![0u8; 1024];
+
+    println!("Recording... Delaying playback by 1s. Press Ctrl+C to stop.");
+
+    loop {
+        // 1. 录制原始 PCM
+        let read = recorder.read(&mut pcm_in)?;
+        if read == config.frame_size {
+            // 2. 编码并存入队列
+            let opus_len = codec.encode(&pcm_in, &mut opus_buf)?;
+            let opus_data = opus_buf[..opus_len].to_vec();
+            delay_queue.push_back((Instant::now(), opus_data));
+        }
+
+        // 3. 处理延迟播放：检查队列头部数据是否已等待超过 1s
+        while let Some((timestamp, _)) = delay_queue.front() {
+            if timestamp.elapsed() >= delay_duration {
+                let (_, opus_data) = delay_queue.pop_front().unwrap();
+
+                let mut pcm_out = vec![0i16; config.frame_size * config.channels as usize];
+                let decoded_len = codec.decode(&opus_data, &mut pcm_out)?;
+
+                if decoded_len == config.frame_size {
+                    // 4. 播放还原后的 PCM
+                    player.write(&pcm_out)?;
+                }
+            } else {
+                // 头部数据还未到 1s，由于队列是按时间排序的，后面的肯定也没到
+                break;
+            }
+        }
    }
 }