The function dec1() do two completly unrelated things. Split the rms calculation out of it.
The function dec1() do two completly unrelated things. Split the rms calculation out of it.

git-svn-id: a4d7c1866f8397a4106e0b57fc4fbf792bbdaaaf@13604 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg