install it
sudo add-apt-repository ppa:maarten-baert/simplescreenrecorder
sudo apt-get update
sudo apt-get install simplescreenrecorder

// create sound file from text
espeak -f example.txt -s 120 -w example.wav
//merge audio and vid streams overwriting sound on dest vid
 ffmpeg -i testOccSyd.mp4 -i example.wav -c:v copy -c:a aac -strict experimental
 -map 0:v:0 -map 1:a:0 output.mp4

Page one after splash screen of SSR for Linux and a program to record in a virtual machine on right ( my windows xp game called Total Hydro Commander you can get here )  Click on the select window button then on the window ( in this case the one with the virtual machine running on the game on right ) this will add the co-ordinates to the program A good idea is to record the smallest window you can get away with to save CPU cycles and you can click on continue to go to page 2 ....

Page 2
Select the file name test.mp4 don't forget to add .mp4 to the end of the name ... and the media format for example MP4 or WebM and continue to the next page

Page 3
you can lower CPU intensive operations here and view the recordings size change dynamically here
Just cick on Start recording to begin then Save button after you have done your recording