mapleafgo
ec168be827
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统一音频输出采样率为 44100Hz，使用 go-audio-resampler 库实现 Windowed Sinc + Polyphase FIR 算法（VeryHigh 28-bit 精度）， 替代原有的线性插值透传方案。 主要变更： - 新增 sincResampler：三阶段 Read 循环（填充→处理→Flush） - 双缓冲区架构避免输出样本丢失，复用内存减少 GC 压力 - WAV/MP3/BGM 播放管线全部接入 Sinc 重采样器 - 移除旧的 linearResampler 和透传模式 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
149 lines
3.5 KiB
Go
149 lines
3.5 KiB
Go
package audio
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import (
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"io"
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resampling "github.com/tphakala/go-audio-resampler"
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"go.uber.org/zap"
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)
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// minProcessSamples 是 FIR 滤波器产生可靠输出所需的最小输入样本数
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const minProcessSamples = 64
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// needsResampling 检查是否需要重采样
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func needsResampling(sourceRate int) bool {
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return sourceRate != UniversalSampleRate
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}
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// sincResampler 基于 go-audio-resampler 的高质量重采样器
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// 使用 Windowed Sinc + Polyphase FIR 算法，专业级音质
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type sincResampler struct {
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decoder io.Reader
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resampler resampling.Resampler
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inputBuf []float64 // 输入缓冲区：int16→float64 转换后暂存
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outputBuf []float64 // 输出缓冲区：Process/Flush 产出但未消费的样本
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inputBytes []byte // 复用的字节读取缓冲区
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flushed bool // 是否已完成 Flush
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eof bool // 上游是否已返回 EOF
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}
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// newSincResampler 创建高质量 Sinc 重采样器
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// 使用场景：大广场音效、高保真音乐
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func newSincResampler(src io.Reader, inRate, outRate, channels int) io.Reader {
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if inRate == outRate {
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return src
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}
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config := &resampling.Config{
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InputRate: float64(inRate),
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OutputRate: float64(outRate),
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Channels: channels,
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Quality: resampling.QualitySpec{
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Preset: resampling.QualityVeryHigh,
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},
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}
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r, err := resampling.New(config)
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if err != nil {
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zap.S().Warnf("Sinc 重采样器创建失败，降级为透传: %v", err)
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return src
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}
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return &sincResampler{
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decoder: src,
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resampler: r,
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inputBuf: make([]float64, 0, 4096),
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outputBuf: make([]float64, 0, 4096),
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inputBytes: make([]byte, 1024),
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}
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}
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func (r *sincResampler) Read(p []byte) (int, error) {
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if len(p) < 2 {
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return 0, io.ErrShortBuffer
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}
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maxSamples := len(p) / 2
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// 主循环：直到有足够输出数据或 EOF
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for len(r.outputBuf) < maxSamples {
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// 阶段1：从上游读取数据，累积到 inputBuf
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for len(r.inputBuf) < minProcessSamples && !r.eof {
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nn, readErr := r.decoder.Read(r.inputBytes)
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if readErr != nil && readErr != io.EOF {
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return 0, readErr
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}
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if readErr == io.EOF || nn == 0 {
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r.eof = true
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break
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}
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sampleCount := nn / 2
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for i := range sampleCount {
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sample := int16(r.inputBytes[i*2]) | int16(r.inputBytes[i*2+1])<<8
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r.inputBuf = append(r.inputBuf, float64(sample)/32768.0)
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}
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}
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// 阶段2：处理输入数据
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if len(r.inputBuf) > 0 {
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output, err := r.resampler.Process(r.inputBuf)
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if err != nil {
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return 0, err
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}
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r.inputBuf = r.inputBuf[:0]
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if len(output) > 0 {
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r.outputBuf = append(r.outputBuf, output...)
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}
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continue
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}
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// 阶段3：EOF 且 inputBuf 为空，调用 Flush 获取尾部残留
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if r.eof && !r.flushed {
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r.flushed = true
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flushed, err := r.resampler.Flush()
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if err != nil {
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return 0, err
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}
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if len(flushed) > 0 {
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r.outputBuf = append(r.outputBuf, flushed...)
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}
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continue
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}
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// 无更多数据可获取
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break
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}
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if len(r.outputBuf) == 0 {
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return 0, io.EOF
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}
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// 写入输出
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n := min(len(r.outputBuf), maxSamples)
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writeFloat64ToLE16(p, r.outputBuf[:n])
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if n < len(r.outputBuf) {
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r.outputBuf = r.outputBuf[n:]
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} else {
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r.outputBuf = r.outputBuf[:0]
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}
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return n * 2, nil
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}
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// writeFloat64ToLE16 将 float64 样本转换为 int16 LE 写入 buf
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func writeFloat64ToLE16(buf []byte, samples []float64) {
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for i, s := range samples {
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if s > 1.0 {
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s = 1.0
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} else if s < -1.0 {
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s = -1.0
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}
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v := int32(s * 32768.0)
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if v > 32767 {
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v = 32767
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}
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buf[i*2] = byte(v)
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buf[i*2+1] = byte(v >> 8)
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}
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}
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