[FFmpeg-trac] #10336(undetermined:new): Ultra low framerate issues

[FFmpeg]

#10336: Ultra low framerate issues
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             Reporter:  Noitarud     |                    Owner:  (none)
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
                                     |  undetermined
              Version:  unspecified  |               Resolution:
             Keywords:  FPS          |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
Description changed by Noitarud:

Old description:

> I have found two reasons to lower framerates to fractional: video is a
> title image only, or it is of a presentation (and moreso when the person
> is waving the camera around).
> I tested it with two music videos and I encountered some issues:
>
> A) Video is no longer the correct length. Will have to scale it.
> Video #1: original 4:53 @30FPS  to 5:10 @0.2FPS, or to 5:20 @0.1FPS
> Video #2: original 4:15 @23.976 to 4:30 @0.2FPS, or to 4:50 @0.1FPS
> So recommend rounding the FPS up or down to suit the length if last frame
> cannot be shorter (not to impact B below, last frame central to regular
> size span or last frame).
>
> B)Frame chosen as representative for the period is at the start of the
> span not the middle. Thus, if first frame is black then I see that for
> the first while.
>
> Quite sure I just used the -r 0.1 option only for this. Old version used
> (I did check older issues) N-64167-gca35037.

New description:

 I have found two reasons to lower framerates to fractional: video is a
 title image only, or it is of a presentation (and moreso when the person
 is waving the camera around).
 I tested it with two music videos and I encountered some issues:

 A) Video is no longer the correct length. Will have to scale it.
 Video #1: original 4:53 @30FPS  to 5:10 @0.2FPS, or to 5:20 @0.1FPS
 Video #2: original 4:15 @23.976 to 4:30 @0.2FPS, or to 4:50 @0.1FPS
 So recommend rounding the FPS up or down to suit the length if last frame
 cannot be shorter (if frame can be shorter, is not to impact B below, last
 frame central to regular size span or last frame).

 B)Frame chosen as representative for the period is at the start of the
 span not the middle. Thus, if first frame is black then I see that for the
 first while.

 Quite sure I just used the -r 0.1 option only for this issue. Old version
 of FFM used (I did check older issues in case someone had done it already)
 N-64167-gca35037.

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Ticket URL: <https://trac.ffmpeg.org/ticket/10336#comment:3>
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