[Feature request] Define subtitle font in pixels

Hi,

Would it be possible to set font size in pixels?

For example translated subtitles are going to be burned-in using Lucida Grande at 60px. We could pass this info to translators, so their preview would match the final output. Of course font size would have to be scaled to match the preview size.

Currently the font size is set as a percentage which doesn't really mean anything.

*Additional feature - toggle to mark the font size as defined for Full HD (1920x1080), so if user loads a video at different size, the font size would be scaled proportionally to match the width. Example:

Font set to 60px.

  • with 1920x1080 video, it's displayed at 60px
  • with 1280x720 video, it's displayed at 66% * 60px = 40px
  • with vertical video (1080x1920), it would be 56% * 60px = 34px.