[FFmpeg-user] Some questions about PTS

[Nicolas George]

Michael Koch (12020-08-28):
> -- The timebase of a video (TB in setpts filter) is expressed in the unit
> [s] (seconds).
> -- The framerate of a video (FR in setpts filter) is expressed in the unit
> [s^-1] (1/seconds).
> -- In many cases the timebase is the reciprocal of the framerate, but this
> isn't always the case.

Looks mostly correct.

> -- If the timebase is the reciprocal of the framerate, a stream can be
> delayed by x frames using setpts=PTS+x
> -- In the more general case for arbitrary timebase and framerate, a stream
> can be delayed by x frames using setpts=PTS+x/(FR*TB)

"Delayed by x frame" is only relevant for a stream with constant frame
per second. Please think first and foremost about timestamps and as
little as possible in terms of number of frames.

Regards,

-- 
  Nicolas George
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