shared between the RM demuxer and the RTSP/RDT parser; both use the same
timebase. See discussion in "[PATCH] rmdec.c: move av_set_pts_info()" on ML.



git-svn-id: file:///var/local/repositories/ffmpeg/trunk@15164 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b