[FFmpeg-trac] #2658(avformat:new): Written mp4 with h264/AAC doesnt use fps as video timebase (discrepancy with libav)

[FFmpeg]

#2658: Written mp4 with h264/AAC doesnt use fps as video timebase (discrepancy
with libav)
------------------------------------+------------------------------------
             Reporter:  Lastique    |                    Owner:
                 Type:  defect      |                   Status:  new
             Priority:  normal      |                Component:  avformat
              Version:  1.2.1       |               Resolution:
             Keywords:  mov, libav  |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
------------------------------------+------------------------------------

Comment (by Lastique):

 > To ensure the timebase is precisse enough to allow precissely specifying
 timestamps of frames. Also some containers like mpeg-ps/ts use a fixed
 90khz timebase that cannot be changed.

 I think, that's the container details libavformat is supposed to abstract
 away from the user. Timestamp conversion is performed in any case - either
 inside the muxer or in the user's code, when it discovers what time base
 the muxer wants. My point is that the muxer is a better place for the
 conversion since it eases life for the user and makes libavformat
 interface more uniform across different containers.

 You could report the "desired" time base through some new interface before
 the user opens the context so that when the user has the liberty of
 choosing his internal timestamp granularity he can use the time base that
 is best for the container. In this case the muxer wouldn't have to perform
 the conversion.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/2658#comment:6>
FFmpeg <http://ffmpeg.org>
FFmpeg issue tracker