v0.2.18

• Fix bug in filename handling when using the ffmpeg concatenation filter, which is used for multiperiod manifests when the technical characteristics of the different periods make it possible to concatenate them without reencoding. Filenames were not properly escaped when passed as arguments to the filter_complex commandline argument.
• Add support for subtitles that use SegmentBase addressing.
• Subtitles in STPP format (a data stream in MP4 fragments) are now converted to TTML format. The XML data stream is extracted using ffmpeg. If the conversion is successful it will be saved to a file with the same name as the output file, but with a .ttml extension.