Open Source software can play a critical role for the roll-out of broadcast standards. This is also true for new caption and subtitle standards. The focus on the presentation will be on the OS Subtitle Conversion Framework (SCF). SCF consists of different software modules that aim at a faster and conformant adoption of the EBU-TT standard, an XML based subtitle standard defined by the EBU. Apart from SCF also other OS software that are important for the implementation of subtitles standards will be discussed (e.g. mp4box from GPAC or the WebVTT parser from Anne van Kesteren).