fm-rds-tx/internal/audio/resample.go

package audio

type ResampledSource struct {
    src      *WAVSource
    ratio    float64
    position float64
}

func NewResampledSource(src *WAVSource, targetSampleRate float64) *ResampledSource {
    ratio := 1.0
    if src != nil && src.SampleRate > 0 && targetSampleRate > 0 {
        ratio = float64(src.SampleRate) / targetSampleRate
    }
    return &ResampledSource{src: src, ratio: ratio}
}

func (s *ResampledSource) NextFrame() Frame {
    if s.src == nil || len(s.src.frames) == 0 {
        return NewFrame(0, 0)
    }
    idx := int(s.position) % len(s.src.frames)
    frame := s.src.frames[idx]
    s.position += s.ratio
    for s.position >= float64(len(s.src.frames)) {
        s.position -= float64(len(s.src.frames))
    }
    return frame
}