103 lines
2.1 KiB
Go
103 lines
2.1 KiB
Go
package audio
|
|
|
|
import (
|
|
"math"
|
|
"time"
|
|
)
|
|
|
|
// Take returns a Streamer which streams s for at most d duration.
|
|
//
|
|
// The returned Streamer propagates s's errors throught Err.
|
|
func Take(d time.Duration, s Streamer) Streamer {
|
|
return &take{
|
|
s: s,
|
|
currSample: 0,
|
|
numSamples: int(math.Ceil(d.Seconds() * SampleRate)),
|
|
}
|
|
}
|
|
|
|
type take struct {
|
|
s Streamer
|
|
currSample int
|
|
numSamples int
|
|
}
|
|
|
|
func (t *take) Stream(samples [][2]float64) (n int, ok bool) {
|
|
if t.currSample >= t.numSamples {
|
|
return 0, false
|
|
}
|
|
toStream := t.numSamples - t.currSample
|
|
if len(samples) < toStream {
|
|
toStream = len(samples)
|
|
}
|
|
n, ok = t.s.Stream(samples[:toStream])
|
|
t.currSample += n
|
|
return n, ok
|
|
}
|
|
|
|
func (t *take) Err() error {
|
|
return t.s.Err()
|
|
}
|
|
|
|
// Seq takes zero or more Streamers and returns a Streamer which streams them one by one without pauses.
|
|
//
|
|
// Seq does not propagate errors from the Streamers.
|
|
func Seq(s ...Streamer) Streamer {
|
|
i := 0
|
|
return StreamerFunc(func(samples [][2]float64) (n int, ok bool) {
|
|
for i < len(s) && len(samples) > 0 {
|
|
sn, sok := s[i].Stream(samples)
|
|
samples = samples[sn:]
|
|
n, ok = n+sn, ok || sok
|
|
if !sok {
|
|
i++
|
|
}
|
|
}
|
|
return n, ok
|
|
})
|
|
}
|
|
|
|
// Mix takes zero or more Streamers and returns a Streamer which streames them mixed together.
|
|
//
|
|
// Mix does not propagate errors from the Streamers.
|
|
func Mix(s ...Streamer) Streamer {
|
|
return StreamerFunc(func(samples [][2]float64) (n int, ok bool) {
|
|
var tmp [512][2]float64
|
|
|
|
for len(samples) > 0 {
|
|
toStream := len(tmp)
|
|
if toStream > len(samples) {
|
|
toStream = len(samples)
|
|
}
|
|
|
|
// clear the samples
|
|
for i := range samples[:toStream] {
|
|
samples[i] = [2]float64{}
|
|
}
|
|
|
|
snMax := 0 // max number of streamed samples in this iteration
|
|
for _, st := range s {
|
|
// mix the stream
|
|
sn, sok := st.Stream(tmp[:toStream])
|
|
if sn > snMax {
|
|
snMax = sn
|
|
}
|
|
ok = ok || sok
|
|
|
|
for i := range tmp[:sn] {
|
|
samples[i][0] += tmp[i][0]
|
|
samples[i][1] += tmp[i][1]
|
|
}
|
|
}
|
|
|
|
n += snMax
|
|
if snMax < len(tmp) {
|
|
break
|
|
}
|
|
samples = samples[snMax:]
|
|
}
|
|
|
|
return n, ok
|
|
})
|
|
}
|