[FFmpeg-trac] #10820(undetermined:new): FFprobe reports 50Hz framerate for 25Hz MPEG1 input file

[FFmpeg]

#10820: FFprobe reports 50Hz framerate for 25Hz MPEG1 input file
-------------------------------------+-------------------------------------
             Reporter:  t.rapp       |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:  ffprobe      |               Blocked By:
  regression                         |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Starting with FFmpeg v6.1 some MPEG1 input file is reported by FFprobe
 with 50Hz video framerate. In previous versions 25Hz have been reported,
 and converting the file with FFmpeg v6.1 into another format (like AVI)
 will generate a 25Hz output file.

 How to reproduce:
 {{{
 % ffprobe -select_streams v -show_entries "stream=r_frame_rate" -i
 temp/2C491696.mpg

 ffprobe version N-113240-g6d2f645 Copyright (c) 2007-2024 the FFmpeg
 developers
   built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.12) 20160609
   configuration: --enable-gpl --disable-network --enable-libsoxr --enable-
 libtwolame --enable-libmp3lame --enable-libvorbis --enable-libfreetype
 --enable-libx264 --enable-static --disable-shared --progs-suffix=-dbg
 --enable-debug --disable-optimizations --enable-extra-warnings --assert-
 level=2 --prefix=/usr/local
   libavutil      58. 36.101 / 58. 36.101
   libavcodec     60. 37.100 / 60. 37.100
   libavformat    60. 20.100 / 60. 20.100
   libavdevice    60.  4.100 / 60.  4.100
   libavfilter     9. 17.100 /  9. 17.100
   libswscale      7.  6.100 /  7.  6.100
   libswresample   4. 13.100 /  4. 13.100
   libpostproc    57.  4.100 / 57.  4.100
 Input #0, mpeg, from 'temp/2C491696.mpg':
   Duration: 00:00:21.10, start: 22652.867033, bitrate: 1260 kb/s
   Stream #0:0[0x1e0]: Video: mpeg1video, yuv420p(tv, progressive), 720x576
 [SAR 1:1 DAR 5:4], 104857 kb/s, 25 fps, 50 tbr, 90k tbn
       Side data:
         cpb: bitrate max/min/avg: 0/0/0 buffer size: 278528 vbv_delay: N/A
   Stream #0:1[0x1c0]: Audio: mp2, 48000 Hz, stereo, s16p, 192 kb/s
 [STREAM]
 r_frame_rate=50/1
 [SIDE_DATA]
 [/SIDE_DATA]
 [/STREAM]
 }}}

 Running `git bisect` points to commit
 e930b834a928546f9cbc937f6633709053448232 having introduced the changed
 output value.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10820>
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