[FFmpeg-trac] #11126(ffmpeg:new): Filter "setpts=PTS-STARTPTS" in 2-pass may cause abnormal bitrate allocation

[FFmpeg]

#11126: Filter "setpts=PTS-STARTPTS" in 2-pass may cause abnormal bitrate
allocation
-------------------------------------+-------------------------------------
             Reporter:  Saul Baker   |                    Owner:  (none)
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:  ffmpeg
              Version:  git-master   |               Resolution:
             Keywords:  regression   |               Blocked By:
  setpts 2-pass                      |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Comment (by MasterQuestionable):

 ͏    Don't quite understand your previous words.
 ͏    Post interpreted for reference:

 [ Saul Baker @ CE 2024-08-06 13:27:57 UTC:
 https://trac.ffmpeg.org/ticket/11126#comment:17
 ͏    Yes, and indeed a parameterless "setpts": as "PTS" is the default
 expression.

 ͏    fa110c32b5168d99098dc0c50c6465054cf9d20b
 ͏    f121d954ac89060cb7b07da230479cffe5bf9e5c
 ͏    ; mean the FPS and duration stripping apply regardless of the actual
 expression:
 ͏    Seemingly intended as fix for: https://trac.ffmpeg.org/ticket/10886

 ͏    Anton's rationale about them not being accurate after "setpts"
 application, does seem reasonable; but I'm unsure:
 ͏    How is it expected to be re-applied if needed inside the filtergraph,
 without externally scripting a literal into the FPS filter?
 ͏    If this combined behavior with 2-pass outweighs the perceived
 correctness of dropping the FPS and durations, rather than providing a
 param to explicitly do the same?

 ͏    A bit of a tension here between "translating" the PTS under which the
 FPS and duration are constant, and "transforming" them in arbitrary ways:
 ͏    The filter can do both and the dropping of the FPS and duration only
 really holds for the latter. ]
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11126#comment:19>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker