add informations about input file as user comments

It would be nice if ffmpeg2theora could add as comments informations about the original input file in the output file. ffmpeg2theora already adds the string
ENCODER=ffmpeg2theora-0.23
that can be viewed with tools like ogginfo.

I'd like to see especially the original input file formats that are also printed during encoding:

Stream #0.0: Video: mpeg4, yuv420p, 576x320 [PAR 1:1 DAR 9:5], 23.98 tbr, 23.98 tbn, 23.98 tbc
Stream #0.1: Audio: mp3, 48000 Hz, stereo, s16, 112 kb/s

Eventually could also be added the original file name and container, and a command line switch to enable or disable these.

Thanks.