Once the subtitles and captions have been created and checked, they are ready for transmission. There are essentially two types of transmission. Subtitle and caption data is either sent for time-of-air transmission, when the pre-prepared files are matched to the programming ahead of transmission, or, are transcoded into a file-based video asset.

Time-of-air transmission needs careful monitoring to ensure that files are correct and will automatically bind to video assets at the right time. For the transmission of repurposed files, where file formats may be different, the transmission software provides multiformat transmission with transcoding in real-time and a retiming function to avoid subtitle or caption transmission delay.

Softel has developed Swift™ TX, subtitle and caption transmission software. Siwft TX supports a large variety of file formats and features real-time transcoding as well as a range of automation interfaces to ensure that the correct subtitles and captions are transmitted at the right time.