72 lines
2.6 KiB
Rust
72 lines
2.6 KiB
Rust
#![cfg(target_os = "linux")]
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use crate::audio::config::AudioConfig;
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use alsa::Direction;
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use alsa::pcm::{Access, Format, HwParams, PCM};
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use anyhow::{Context, Result};
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pub struct AudioPlayer {
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pcm: PCM,
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}
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impl AudioPlayer {
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pub fn new(config: &AudioConfig) -> Result<Self> {
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let pcm = PCM::new(&config.playback_device, Direction::Playback, false)
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.context("Failed to open playback PCM device")?;
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setup_pcm(&pcm, config.sample_rate, config.channels)?;
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Ok(Self { pcm })
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}
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pub fn write(&self, buffer: &[i16]) -> Result<usize> {
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let res = self.pcm.io_i16()?.writei(buffer);
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match res {
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Ok(written) => Ok(written),
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Err(e) => {
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// Buffer Underrun，即播放缓冲区的数据被耗尽，导致音频流中断
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if e.errno() == 32 {
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// 恢复音频流状态
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self.pcm.prepare()?;
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// 重新获取 IO 对象并尝试写入数据
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self.pcm
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.io_i16()?
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.writei(buffer)
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.context("Failed to write to playback device after recovery")
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} else {
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Err(e).context("Failed to write to playback device")
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}
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}
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}
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}
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pub fn prepare(&self) -> Result<()> {
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self.pcm.prepare().context("Failed to prepare PCM")
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}
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}
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fn setup_pcm(pcm: &PCM, sample_rate: u32, channels: u16) -> Result<()> {
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let hwp = HwParams::any(pcm).context("Failed to get HwParams")?;
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hwp.set_access(Access::RWInterleaved)?;
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hwp.set_format(Format::s16())?;
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hwp.set_rate(sample_rate, alsa::ValueOr::Nearest)?;
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hwp.set_channels(channels as u32)?;
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// 设置较大的缓冲区以减少由于调度抖动和设备重初始化导致的断音/卡顿
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// 使用 100ms 缓冲区，既能防止 underrun，又不会引入过大延迟
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let buffer_size = (sample_rate as f64 * 0.1) as u32; // 100ms 缓冲
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let period_size = buffer_size / 4; // 25ms 周期
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hwp.set_buffer_size_near(buffer_size as alsa::pcm::Frames)?;
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hwp.set_period_size_near(period_size as alsa::pcm::Frames, alsa::ValueOr::Nearest)?;
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pcm.hw_params(&hwp).context("Failed to set HwParams")?;
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let swp = pcm.sw_params_current()?;
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// 设置 start_threshold，当缓冲区有 1 个 period 数据时就开始播放
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// 这样可以快速启动，同时保持足够的缓冲余量
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swp.set_start_threshold(period_size as alsa::pcm::Frames)?;
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pcm.sw_params(&swp)?;
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pcm.prepare()?;
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Ok(())
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}
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