BDSup2Sub - convert and tweak bitmap subtitle streams (VobSub,BD-SUP,BDN XML,HD-SUP)
BDSup2Sub is a tool initially written to convert captions demuxed from a Blu-Ray transport stream (M2TS) into the DVD VobSub format (SUB/IDX) used by many DVD authoring tools - hence the name. Many more features were added over time as was support for other formats. So in the meantime the name seems a little inappropriate. In a nutshell, it's a subtitle conversion tool (for image based formats) with scaling capabilities and some other nice features.