I have no idea how to change the engine of kaffeine to gstreamer.

But I installed totem-gstreamer, and I run it with "totem --display :0.1". It complained about unknown switch --display, but it opened on the secondary display. And when trying to play the MPEG file it crashed and printed the message:

The program 'totem' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadMatch (invalid parameter attributes)'.
(Details: serial 32 error_code 8 request_code 143 minor_code 3)
(Note to programmers: normally, X errors are reported asynchronously;
that is, you will receive the error a while after causing it.
To debug your program, run it with the --sync command line
option to change this behavior. You can then get a meaningful
backtrace from your debugger if you break on the gdk_x_error() function.)