Redirect to same page, display different content

Is it possible to use FFMPEG with spaces like the example below:

shell_exec("ffmpeg -i .my file name.mp4 -ss 00:00:10.4 -vframes 1 my file name_thumbnail.jpg");

I’m trying to convert files with spaces in between them but ffmpeg doesn’t seem to recognize it…is there a way to do this or no? I’ve done research but I can’t seem to find a correct answer…I’ve even tried the 2 examples below:

shell_exec("ffmpeg -i .my%file%name.mp4 -ss 00:00:10.4 -vframes 1 my%file%name_thumbnail.jpg");

shell_exec("ffmpeg -i .my%20file%20name.mp4 -ss 00:00:10.4 -vframes 1 my%20file%20name_thumbnail.jpg");