[FFmpeg-user] Force Subtitle Detection

[petesea at frontier.com]

Is it possible to use ffprobe to detect the number of forced subtitles?

I've found I can use "-count_frames" and look at the 
"streams.stream.X.nb_read_frames" entry to determine the number of 
subtitles in a particular stream (at least I'm pretty sure that's what 
it's telling me).  But I can't see a way to figure out the number of 
forced subtitles.  Is there a way?