Use ffmpeg to sequentially overlay a folder of audio files

ffmpeg-sequentialMerge.go

package main

import (
	"fmt"
	"os/exec"
	"strconv"
)

func main() {
	countdown(4)
}

func countdown(seconds int) {
	if seconds == 0 {
		fmt.Println("Complete!")
	} else {
		nextCount := seconds - 1
		wav1 := strconv.Itoa(seconds) + ".wav"
		wav2 := strconv.Itoa(nextCount) + ".wav"
		newWav := "newwav" + strconv.Itoa(nextCount) + ".wav"
		fmt.Println(wav1)
		fmt.Println(wav2)
		fmt.Println(newWav)
		cmd2 := exec.Command(
			"ffmpeg",
			"-y",
			"-i",
			wav1,
			"-i",
			wav2,
			"-filter_complex",
			"[0:0][1:0] amix=inputs=2:duration=longest",
			"-c:a",
			"libmp3lame",
			newWav,
		)
		cmd2.Start()
		countdown(nextCount)
	}
}