[FFmpeg-user] Filter documentation -- PTSs

Mark Filipak (ffmpeg) markfilipak at bog.us
Mon Feb 15 01:47:10 EET 2021


Disclosure: Everything that follows may be wrong.

I reckon that, except for a few filters, the important metric is PTS, not the frame #s assigned at a 
filter's input node nor its wall-clock arrival time at a filter's input node. For example, 
'interleave' performs frame interleaves based on the PTSs of incoming frames -- at least, that's 
what I think.

Am I correct?

If so, wouldn't it be helpful if filter documentation included how it generates PTSs?

Filter documentation should include:
1, More than just the names of directives (i.e. "options") -- some do, some don't,
2, Input specifications that include
2.1, The minimum number of output frames,
2.2, The number of output frames per input frame, and
2.3, Indication of the frames that are dropped (if any), for example: "first frame is dropped", 
"last 2 frames are dropped", etc., and
3, The mathematical formula employed to calculate output PTSs.

I urge responses from all who are critical -- You know who you are! Perhaps someday we will be 
allowed to contribute. There are several of us who are critical. If allowed, we could resolve all 
issues for all filters in just a few days.

-- 
Any journey, no matter how long, is just a series of small steps.
"Government is the problem!" -- 1982 and onward.
"_______ is the enemy of the people!" -- 2016 and onward.
"You have to fight like hell or you're not going to have a country!" -- Jan 6, 2021.
It isn't the distance that's important, it's the direction.


More information about the ffmpeg-user mailing list