I'm confused as to whether you have the names and know the format, and they are always something like "video-$NUMBER.mp4", or whether you have a list of files, and just want to iterate through them.
For a known format, where the number is a monotonically increasing integer:
numFiles = 10
for i=0 to numFiles
filename = "video-"+i.toStr()+".mp4"
' do something
end for
For a list of files:
files = ["file1.mp4", "other.mp4", "file23534.mp4"]
for each file in files
' file contains filename from files array
' do something
end for
Or am I just completely missing your point?