[FFmpeg-user] DTSs & PTSs in MPEG2-TS streams

Mark Filipak markfilipak.imdb at gmail.com
Thu Feb 1 08:15:21 EET 2024

FFmpeg assigns DTSs & PTSs to P-frames and B-frames in MPEG2-TS streams. How does it determine those 
DTSs & PTSs?

Since DTSs & PTSs don't actually exist for P-/B-frames in MPEG2-TS streams, FFmpeg must have a way 
that's unknown to me.

I'm seeing some strange things. They can't be as strange as they look because they look disastrous. 
At issue is the cause of non-monotonous DTSs and obviously bogus DTSs for P-frames such as 

I'm not trying to mysterious. I'm trying to tread carefully because I've been accused of being a 
troll. How anyone could think I'm a troll when I've been here for years and I've always used my real 
name, everywhere on the Internet, is beyond me. And, no, I'm not writing a book. And I'm 
markfilipak.imdb because that's a leftover gmail account that still works but is otherwise useless 
to me since imdb closed its forum several years ago. So, please, no flames.

I have been investigating trimming and concatenation problems full time for many weeks and will 
present a report here when I'm done. My preliminary finding is that FFmpeg is creating its own 
problems due to internal fixups, but that's just preliminary and I really hope I'm wrong. I can't 
look at the source code because, though 'C' syntax is no problem for me, actual 'C' code is a black 


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