It checks if the blending will succeed with the formats we use.
It fixes the order of the RGB components (close #4919).

It is quite useless and will confuse users who want to add "film grain"
to the video.

At least the ISDB-T standard export version uses sub-kHz precision
(never mind that one band occupies several megahertz in width).

It closes #4861.
It fixes playback when the rate cannot be respected (like with dvb/udp/...)
or need to be requested to the access_demux (rtsp).

It is unrelated to dvd/bd LPCM.

This is a first step to re-organize the interface, more to come

Some people find it more readable.

It allows to avoid full rgb <-> yuv conversion at a latter stage.

The shadow is enabled by default.

They should be prefixed by '#' but it is not always done...

The quality is a lot better than what we originaly had.

The placement and thickness of the underline is now global to a whole
line of text.

Created a structure to gather all informations needed to draw one character.
It simplify a bit the code.

It will be replaced by more specific options.

Outline support is temporary removed.
Underlining is a bit improved (quality and speed wise).
Overlapping over the optional background box is improved (quality wise).