• Shifted -truecolor setting from the outer image sequence into the parenthesised image sequence, to fix weird coloured box that were appearing on certain pages.

• Refactored input/output options variables and methods from FFmpegCommand into ShellCommand, so that all subclasses can use them. ...

• Enhanced ConvertCommand to do more intelligent processing of PDF frames of varying sizes and aspect ratios.

• When appending a concat filter, check that the segments list actually contains something.

• Added white background and removed transparency for PDF to PNG image conversions.

• Moved shell command classes into separate module.