ffmpeg error code 1

[acedigibits]

i am able to run ffprobe and get details for input path.

However if i use ffmpeg command listed below :

ffmpeg.exec("-i someinput.mp4 -vn -c:a copy out.mp3", (success) => alert(success), (failure) => alert(failure));

to convert that same video to mp3 , i get error code 1. I have permission to write to external storage and output path is set to external storage. i am unable to pinpoint what is the exact issue as i have tried all combination of output path.