Bjarne Øverli
60 lines
1.3 KiB
Go
60 lines
1.3 KiB
Go
package player
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import (
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"sync"
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"github.com/gopxl/beep/v2"
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)
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// Tap is a streamer wrapper that copies samples into a ring buffer
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// for real-time FFT visualization. It sits in the audio pipeline
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// between the volume control and the speaker controller.
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type Tap struct {
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s beep.Streamer
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mu sync.Mutex
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buf []float64
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pos int
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size int
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}
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// NewTap wraps a streamer with a ring buffer of the given size.
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func NewTap(s beep.Streamer, bufSize int) *Tap {
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return &Tap{
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s: s,
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buf: make([]float64, bufSize),
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size: bufSize,
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}
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}
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// Stream passes audio through while capturing a mono mix into the ring buffer.
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func (t *Tap) Stream(samples [][2]float64) (int, bool) {
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n, ok := t.s.Stream(samples)
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t.mu.Lock()
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for i := 0; i < n; i++ {
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t.buf[t.pos] = (samples[i][0] + samples[i][1]) / 2
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t.pos = (t.pos + 1) % t.size
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}
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t.mu.Unlock()
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return n, ok
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}
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// Err returns the underlying streamer's error.
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func (t *Tap) Err() error {
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return t.s.Err()
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}
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// Samples returns the last n samples from the ring buffer in chronological order.
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func (t *Tap) Samples(n int) []float64 {
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if n > t.size {
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n = t.size
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}
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out := make([]float64, n)
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t.mu.Lock()
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start := (t.pos - n + t.size) % t.size
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for i := 0; i < n; i++ {
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out[i] = t.buf[(start+i)%t.size]
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}
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t.mu.Unlock()
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return out
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}
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