av/cmd/audio-player/looper0/main.go

129 lines
3.2 KiB
Go

/*
NAME
audio-player/looper0/main.go
AUTHORS
Ella Pietraroia <ella@ausocean.org>
LICENSE
audio player is Copyright (C) 2020 the Australian Ocean Lab (AusOcean)
It is free software: you can redistribute it and/or modify them
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
It is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
in gpl.txt. If not, see http://www.gnu.org/licenses.
*/
// Audio looper for pi0 model
package main
import (
"bytes"
"io"
"log"
"os"
"os/exec"
"sync"
"time"
)
func main() {
soundFile := "/home/pi/48khz.wav"
soundcardPath := "/usr/share/doc/audioInjector/asound.state.RCA.thru.test"
logFile := "audio.log"
// Making log file.
_, err := os.Stat(logFile)
if !os.IsNotExist(err) {
err := os.Remove(logFile)
if err != nil {
log.Fatalf("fatal: error clearing file: %v", err)
}
}
f, err := os.OpenFile(logFile, os.O_RDWR|os.O_CREATE, 0666)
if err != nil {
log.Fatalf("fatal: error opening file %s: %v", logFile, err)
}
defer f.Close()
log.SetOutput(f)
path, err := exec.LookPath("alsactl") // alsactl is a command that ensures the sound will be played through the correct soundcard
if err != nil {
log.Fatalf("fatal: didn't find 'alsactl' executable\n")
} else {
log.Printf("debug: 'alsactl' executable is in '%s'\n", path)
}
for {
cmdInit := exec.Command("alsactl", "-f", soundcardPath, "restore")
err := cmdInit.Run()
if err == nil {
break
}
log.Printf("fatal(ish): cmd.Run() for 'alsactl' failed with '%s'\n", err)
time.Sleep(1 * time.Second)
}
// Making sure that play command is on the pi.
path, err = exec.LookPath("play")
if err != nil {
log.Fatalf("fatal: didn't find 'play' executable\n")
} else {
log.Printf("debug: 'play' executable is in '%s'\n", path)
}
// Infinite loop that outputs audio and gathers debug information.
numPlays := 0
for {
numPlays++
log.Printf("debug: play number: %d\n", numPlays)
cmd := exec.Command("play", soundFile)
var stdoutBuf, stderrBuf bytes.Buffer
stdoutIn, _ := cmd.StdoutPipe()
stderrIn, _ := cmd.StderrPipe()
var errStdout, errStderr error
stdout := io.MultiWriter(os.Stdout, &stdoutBuf)
stderr := io.MultiWriter(os.Stderr, &stderrBuf)
err := cmd.Start()
if err != nil {
log.Fatalf("fatal: cmd.Start() for 'play' failed with '%s'\n", err)
}
var wg sync.WaitGroup
wg.Add(1)
go func() {
_, errStdout = io.Copy(stdout, stdoutIn)
wg.Done()
}()
_, errStderr = io.Copy(stderr, stderrIn)
wg.Wait()
err = cmd.Wait()
if err != nil {
log.Fatalf("fatal: cmd.Run() for 'play' failed with %s\n", err)
}
if errStdout != nil || errStderr != nil {
log.Fatal("fatal: failed to capture stdout or stderr\n")
}
outStr, errStr := string(stdoutBuf.Bytes()), string(stderrBuf.Bytes())
log.Printf("\nout:\n%s\nerr:\n%s\n____________________________________________________\n\n", outStr, errStr)
}
}