Hello everybody.

I am trying to compare two video files which have been encoded in theora at different quality settings. I am (trying) to use mplayer in konsole(bash). My current method (SMASH! CLICK! SMASH!) leaves the two videos slightly out of sync which makes them difficult to compare. So, does anyone know a way to make bash start two different commands at exactly the same time?

Thanks for any help.

You can probably do something like
(that should start them very close to simultaneously).

P.S., I can’t help but think there is some program specifically written for comparing two videos side-by-side (if only I could give you a name).

maybe this? (no guarantees though)

type in both commands in the same line separated by either && or |

&& represents “AND” and will run the second instance after the first instance (only if the first instance exited successfully).

| represents a pipe, and will run both simultaneously (but the input of the second will be borked/uncontrollable because it will be connected to the output of the first).

& is your most likely best option. It will put the first instance in “the background”, allowing the second instance to run. Of course, mplayer is expecting a terminal for stdin, so you might have to tell it otherwise (i.e., use the “-slave” option).

thanks Osar...

Thanks for the replies. As expected && and | do not work. A single & seems to work but they are still a good second out of sync. Am I right in thinking that hardware limitations are now the problem?