Getting errors such as:

E: Package 'gcc-4.7-base:i386' has no installation candidate

E: Unable to locate package libavcodec53

E: Unable to locate package libavutil51

Can anyone tell me how to install the prereqs on Jessie? Or am I missing a repo or something?

deb http://ftp.uk.debian.org/debian/ jessie main contrib non-free

deb-src http://ftp.uk.debian.org/debian/ jessie main contrib non-free

deb http://security.debian.org/ jessie/updates main contrib

deb-src http://security.debian.org/ jessie/updates main contrib

deb http://files.freeswitch.org/repo/deb/debian/ jessie main