.ttxt subtitles style & text outline

[A300]

hello, people I've been muxing .ttxt subtitles into mp4 files with MP4Box but now I'm trying to put a black outline/stroke/border around the text [like the image below] of the subtitles before muxing/embedding them into mp4 files





can anybody tell me what is the code/command for outline color.. like these codes/command
fontSize="45"
backColor="ff ff ff ff"
fontName="Serif"

or is there an application which can put that black outline around the text for me ?

[Selur]

afaik ttxt doesn't have a flag to set the outline color and even if it did, the problem would still be to find a player which supports this. (Yes, ttxt is known to be really restrictive and old.)

Assuming mp4 needs to be the output container, the only choices I see would be:
a. create image based subtitles (idx/sub) and add those. Problem: idx/sub inside mp4 is probably not that wide spread.
b. using hardcoded instead of soft subtitles

[hubblec4]

I thought .ttxt is a chapter format (from Apple for 3gpp).

You could be my chapterEditor (TTXT Format Editor) a try.
It could be that is present in the .ttxt have incorrect settings.
(For example, "text fills region")