fixed potential problem if aspect_ratio_info == 0 for MPEG stream - fixed aspect ratio problem if CODEC_ID_MPEG2VIDEO is used to decode an MPEG1 stream (which is the recommended codec id for mpeg video)


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@2587 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b