[FFmpeg-trac] #6252(undetermined:new): Doesn't get apng duration correctly

[FFmpeg]

#6252: Doesn't get apng duration correctly
-------------------------------------+-------------------------------------
             Reporter:  hxuanyu      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 I have an animated png file generated by APNG Assembler 2.91 which has 10
 frames, each frame duration is 1/25 seconds, so total duration is 10/25
 seconds.

 But when using ffprobe to dump the video frame info
 $ ffprobe.exe animatedfps25.png -show_frames -select_streams v>v
 ffprobe version N-84014-g9e6b269 Copyright (c) 2007-2017 the FFmpeg
 developers
   built with gcc 6.3.0 (GCC)

 frame duration got is 0.06667 second and total duration is 0.6667 second.

 Using ffprobe -loglevel debug we can see in the output

 {{{
 [apng @ 00000000024e2560] decode_fctl_chunk: sequence_number: 0, width:
 768, height: 576, x_offset: 0, y_offset: 0, delay_num: 1, delay_den: 15,
 dispose_op: 0, blend_op: 0
 [apng @ 00000000024e2560] decode_fctl_chunk: sequence_number: 1, width:
 618, height: 293, x_offset: 77, y_offset: 141, delay_num: 1, delay_den:
 15, dispose_op: 0, blend_op: 1
 [apng @ 00000000024e2560] decode_fctl_chunk: sequence_number: 3, width:
 614, height: 285, x_offset: 77, y_offset: 141, delay_num: 1, delay_den:
 15, dispose_op: 2, blend_op: 1
 [apng @ 00000000024e2560] decode_fctl_chunk: sequence_number: 5, width:
 624, height: 293, x_offset: 78, y_offset: 141, delay_num: 1, delay_den:
 15, dispose_op: 2, blend_op: 1
 [apng @ 00000000024e2560] decode_fctl_chunk: sequence_number: 7, width:
 624, height: 285, x_offset: 78, y_offset: 141, delay_num: 1, delay_den:
 15, dispose_op: 2, blend_op: 1
 [apng @ 00000000024e2560] decode_fctl_chunk: sequence_number: 9, width:
 627, height: 293, x_offset: 77, y_offset: 141, delay_num: 1, delay_den:
 15, dispose_op: 0, blend_op: 1
 [apng @ 00000000024e2560] decode_fctl_chunk: sequence_number: 11, width:
 627, height: 292, x_offset: 77, y_offset: 142, delay_num: 1, delay_den:
 15, dispose_op: 2, blend_op: 1
 [apng @ 00000000024e2560] decode_fctl_chunk: sequence_number: 13, width:
 627, height: 292, x_offset: 77, y_offset: 142, delay_num: 1, delay_den:
 15, dispose_op: 0, blend_op: 1
 [apng @ 00000000024e2560] decode_fctl_chunk: sequence_number: 15, width:
 624, height: 291, x_offset: 78, y_offset: 143, delay_num: 1, delay_den:
 15, dispose_op: 0, blend_op: 1
 [apng @ 00000000024e2560] decode_fctl_chunk: sequence_number: 17, width:
 623, height: 290, x_offset: 79, y_offset: 144, delay_num: 1, delay_den:
 15, dispose_op: 0, blend_op: 1
 }}}

 But I'm quite sure in fcTL num = 1, den = 0x19.

 I've attached the apng file for your reference.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6252>
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