* first pass at text subtitle support
* support text subtitles from movies, music videos and other videos
* fixes
* qsv fixes
* vaapi fixes
* update changelog
* wip
* fix songs again
* don't use lists of video and audio input files
* test concat command output
* move concat pipeline
* start to use ffmpeg state
* add ffmpeg state and audio state
* audio state is required
* attach input options directly to input files
* move filters to input files
* add watermark support