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High CPU usage after speaker.Init() called #159
Description
First of all, thanks for Beep and the excellent documentation.
I've written a doorbell in Go that listens to an MQTT channel and then plays a ding-dong noise when a button is pressed. I can deploy the code to multiple hosts on different platforms, which is the appeal of using Go for this.
My code runs as a systemd unit, starts up and initialises the sound streams using Beep's speaker package. However, I've noticed that the baseline CPU usages is pretty high - I have two wav files open and this is using ~15% CPU - even on a puny Celeron box this seems excessive. I've written some minimal code to reproduce this:
package main
import (
"os"
"github.com/faiface/beep"
"github.com/faiface/beep/wav"
"github.com/faiface/beep/speaker"
"time"
)
func main() {
path := os.Args[1]
f, _ := os.Open(path)
streamer, format, _ := wav.Decode(f)
speaker.Init(format.SampleRate, format.SampleRate.N(time.Second/100))
time.Sleep(30 * time.Second)
done := make(chan bool)
speaker.Play(beep.Seq(streamer, beep.Callback(func() {
done <- true
})))
<-done
}
Save the snippet above as play.go and then run with go run play.go <wavfile>. During the time.Sleep (after init, but before the sound is actually played) you can see the usage in top.
I can reduce the CPU usage by reducing the sample rate in the Init call - with time.Second it was down to about 1% - but that still seems high since it should be completely idle. I also tried using buffering as per the wiki, but that didn't make any difference. Did I miss something here? I'm using go1.18.1.
Activity
MawKKe commentedon Apr 1, 2023
It seems that speaker.Init() launches a goroutine that polls update() continuously: https://github.com/faiface/beep/blob/master/speaker/speaker.go#L52, even when nothing is playing. It can be stopped with Close(), but then the speaker needs to be re-Init() before next Play()
MarkKremer commentedon Oct 7, 2023
What I think is happening is that either
os.Open()orwav.Decode()returns an error. This results in theformat.SampleRatebeing0and the internal buffer of the speaker having a size of0. I suspect this messes with one of the loops in some way. Can you confirm this by adding error checks and retrying your code?It may be a nice addition to add a valid sample rate check in
speaker.Init. Although that could invite that we then have to do that everywhere else too.psaffrey commentedon Jan 23, 2024
Sorry to comment on a closed issue and to take such a long time to get back to this: I tried this:
Neither the
os.Open()nor thewav.Decode()return an error. TheSampleRateis reported as 44100, which seems about right. Is there anything else I can try?MarkKremer commentedon Jan 23, 2024
Hey psaffrey, faiface/beep isn't being maintained anymore but we maintain a fork over at gopxl/beep. I've copied your comment to our repo: gopxl/beep#14 (comment). Let's continue the conversation there! :)