* 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
* use blurred cover art as song background
* use channel watermark when cover art is unavailable
* add drawtext to song filter
* cleanup
* force song cover art as png
* fix songs on windows and qsv