[FFmpeg-trac] #8823(avfilter:new): vf_xfade interaction with other filters makes it stop early

[FFmpeg]

#8823: vf_xfade interaction with other filters makes it stop early
-------------------------------------+------------------------------------
             Reporter:  legraphista  |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:  avfilter
              Version:  git-master   |               Resolution:
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+------------------------------------

Comment (by legraphista):

 After some more testing, the following command works as expected:
 {{{
 ffmpeg -f lavfi -i testsrc=r=25:d=5 -f lavfi -i testsrc=r=60:d=5
 -filter_complex "
         [0:v] setpts=PTS-STARTPTS,settb=AVTB [v0];
         [1:v] setpts=PTS-STARTPTS,settb=AVTB,hue=90 [v1];
         [v0][v1] xfade=duration=0.5:transition=wipeleft:offset=4.5
 " test.mp4 -y
 }}}

 The difference between this command and the original post non-working one
 is that i've re-ordered the filter-graph steps to keep the input order.

 It appears that once the order of the steps are not the same as the order
 of the input of xfade, it breaks again:
 {{{
 ffmpeg -f lavfi -i testsrc=r=25:d=5 -f lavfi -i testsrc=r=60:d=5
 -filter_complex "
         [0:v] setpts=PTS-STARTPTS,settb=AVTB,hue=90 [v0];
         [1:v] setpts=PTS-STARTPTS,settb=AVTB [v1];
         [v1][v0] xfade=duration=0.5:transition=wipeleft:offset=4.5
 " test.mp4 -y
 }}}

 In this example, i've re-ordered xfade to take stream 1 then stream 0, but
 processed stream 0 first in the graph, then stream 1

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8823#comment:1>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker