Styleborder's value for a subtitle with transparent dark background (mostly used in Youtube videos)

Question

I'm trying to change background of my .ass subtitle file. This format of subtitle has a property named "Styleborder" and I changed its value from 1 to 3, so it took black background, but I want more transparent black style, just like this one in here:

And here is the code:

• [Script Info] ; This is an Advanced Sub Station Alpha v4+ script. Title: friends.s01e02.720p.bluray.x264--sujaidr ScriptType: v4.00+ Collisions: Normal PlayDepth: 0 Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding Style: Default,Arial,20,&H00FFFFFF,&H0300FFFF,&H00000000,&H02000000,0,0,0,0,100,100,0,0,3,2,1,2,10,10,10,1 [Events] Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text Dialogue: 0,0:00:02.87,0:00:04.29,Default,,0,0,0,,What you guys don't understand is...

Since it uses only Format and Style property and it's not really a .css code, I add a screenshot of this .ass subtitle file:"

Answer 1

Set OutlineColour with alpha channel = &H80000000 for example