hds-audio/playback.go

package main

import (
	"errors"
	"log"
	"os"
	"path/filepath"
	"time"

	"github.com/faiface/beep"
	"github.com/faiface/beep/effects"
	"github.com/faiface/beep/flac"
	"github.com/faiface/beep/mp3"
	"github.com/faiface/beep/speaker"
	"github.com/faiface/beep/wav"
)

var globalStopFlag bool = false
var playingSongData SongData

func playFile(filename string) error {
	if !fileExists(filename) {
		return errors.New("File not exists")
	}
	f, err := os.Open(filename)
	if err != nil {
		log.Fatal(err)
	}

	ext := filepath.Ext(filename)
	var streamer beep.StreamSeekCloser
	var format beep.Format
	if ext == ".mp3" {
		streamer, format, err = mp3.Decode(f)
	} else if ext == ".flac" {
		streamer, format, err = flac.Decode(f)
	} else if ext == ".wav" {
		streamer, format, err = wav.Decode(f)
	} else {
		return errors.New("Not supported file format.")
	}

	if err != nil {
		return err
	}

	defer streamer.Close()

	//Create a new speaker object
	speaker.Init(format.SampleRate, format.SampleRate.N(time.Second/10))

	ctrl := &beep.Ctrl{
		Streamer: beep.Loop(1, streamer),
		Paused:   false,
	}

	volume := &effects.Volume{
		Streamer: ctrl,
		Base:     2,
		Volume:   0,
		Silent:   false,
	}

	//Start the playback counter for loop controls
	playbackCounter := 0

	for deviceStatus.Loop == true || playbackCounter == 0 {

		done := make(chan bool)
		speaker.Play(beep.Seq(volume, beep.Callback(func() {
			done <- true
		})))

		breakOut := false
		go func() {
			for {
				speaker.Lock()
				ctrl.Paused = !deviceStatus.Playing
				volume.Volume = deviceStatus.Gain
				volume.Silent = deviceStatus.Mute
				speaker.Unlock()

				//If the playback finished or the global stopflag is set to true
				if breakOut == true || globalStopFlag == true {
					globalStopFlag = false
					speaker.Clear()
					break
				}
			}
		}()

		//Playback finish. Breakout of the loop
		<-done
		breakOut = true

		//Play again if loop is enabled.
		playbackCounter++
	}

	log.Println("Playback finished")
	deviceStatus.Status = "ready"
	return nil
}