in empty directory

Input picture to a filter is never NULL. And even if it were NULL, the
pointer is dereferenced earlier...

This provides broader details for luma and chroma (0-255 instead of 16-235 and respectively 1-255 instead of 16-240)

and use limits to render underline/strikethrough correctly

Line height is always set to max of the rendered glyphs height.
This causes 'dancing' lines because row height it never the
same, amplified by number of preceding empty rows.

or try #3 in fact :/
This reverts commit 0b6165af.
This reverts commit 24a59363.

Don't end the NAL unit when we reach 0x000000. Refactor since we don't need to
parse separately the start and the end of the NAL unit anymore.