Using ffmpeg for showing wave pic of audio file

Question

I try to get the waves of an audio file as image. I'd like to use FFmpeg but unfortunately I found very less code in this regard and the documentary has just one example. I use it for the first time. So I tried this kotlin code using showwavespic:

val audioFile = File(pathAudioFile)
val wavePic = File(context.filesDir.absolutePath + "/waveform.png")
val cmd = "-y -i ${audioFile.path} showwavespic=s=640x120 ${wavePic.path}"

    try {
        when(FFmpeg.execute(cmd)){
            Config.RETURN_CODE_SUCCESS -> {
                frameLayout.findViewById<ImageView>(R.id.waveView).setImageURI(Uri.fromFile(wavePic)) 
            }

            else -> {
            }
        }

With that command the else-block get's called so it seems to be wrong. This is the example from the documentary

ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png

I don't need the available options (for now) so what is my fault? I'm also not sure if I need the path or the file itself so I tried this:

val cmd = "-i $audioFile waveform.png"

But that doesn't work neither. Can somebody help me with my first steps using FFmpeg?

Answer 1

It works using -i ${audioFile.path} -filter_complex "showwavespic=s=640x120" -frames:v 1 ${wavePic.path}