How to cut a Video and mute it in one step with FFmpeg? -

i tried this:

 "ffmpeg -i input.mp4 -ss 00:00:50.0 -vcodec copy -an -t 20 output.mp4"

because know cutting s

 "ffmpeg -i input.mp4 -ss 00:00:50.0 -codec copy -t 20 output.mp4"

and know muting (deleting sound video):

 "ffmpeg -i input.mp4 -ss 00:00:50.0 -vcodec copy -an -t 20 output.mp4"

it doesnt work. naturally. otherwise wouldnt ask here.

who knows answer? thx

this work:

"ffmpeg -i 'input.mp4' -ss 30 -c copy -an -t 10 '"soundlessoutput.mp4'"

Call