Loop multiple video files to compress them all in one directory?

Question

I'm new to linux. I need some help. I want to compress all files present in a directory with same extension. The output should be with same name and extension. I want to run a shell loop to do this. Here is the command to compress one file.

ffmpeg -i inputfilename.mp4 outputfilename.mp4

I am stuck here. How can I run a loop that to take files from one directory to compress and place in other directory?

Answer 1

Short answer:

for file in *.mp4; do ffmpeg -i "$file" "out/$file" ; done

Long answer is "it depends", but as things don't work and you provide more detail we'll refine it.