mp4 – Command to get only one audio track in output specified by language code with ffmpeg

Ffmpeg Command to get video with only English audio or only one language audio

I tried running ffmpeg -i input_video.ext -map 0:v -map 0:a:language=eng -c:v copy -c:a copy -map_metadata -1 -sn output.mp4

But the output file I got is 0 byte. So can anyone tell me the write command.

I want to get video with only one language audio, I specify with code like eng, hin etc. With subtitles removed and x264 and .mp4 format! I tried getting .mkv which seem to be successful I don’t know whats problem in getting .mp4