Automatic stream selection doesn't work correctly

[Ptaah]

Summary of the bug: Automatic stream selection doesn't work correctly on audio for one particular file.
How to reproduce:

% ffmpeg.exe -y -i noisemeter.mov -f lavfi -i anullsrc=cl=mono -vcodec copy -acodec copy -t 2 test.mov
ffmpeg version n5.1-3-g80d1b8938e-20220801
built with gcc 12.1.0 (crosstool-NG 1.25.0.55_3defb7b)

According to ffmpeg documentation regarding automatic stream selection:

It will select that stream based upon the following criteria:

• for video, it is the stream with the highest resolution,

- for audio, it is the stream with the most channels,

• for subtitles, it is the first subtitle stream found but there’s a caveat. The output format’s default subtitle encoder can be either text-based or image-based, and only a subtitle stream of the same type will be chosen.

This is, however, not the case in this example.

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'noisemeter.mov':
  Metadata:
    major_brand     : qt
    minor_version   : 537199360
    compatible_brands: qt
    creation_time   : 2022-07-13T14:21:10.000000Z
  Duration: 00:02:52.51, start: 0.000000, bitrate: 947309 kb/s
  Stream #0:0[0x1](eng): Video: qtrle (rle  / 0x20656C72), argb(progressive), 3840x2160, 945725 kb/s, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 24k tbn (default)
    Metadata:
      creation_time   : 2022-07-13T14:21:10.000000Z
      handler_name    : Apple Video Media Handler
      vendor_id       : appl
      encoder         : Animation
      timecode        : 00:00:00:00
  Stream #0:1[0x2](eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, stereo, s16, 1536 kb/s (default)
    Metadata:
      creation_time   : 2022-07-13T14:21:10.000000Z
      handler_name    : Apple Sound Media Handler
      vendor_id       :
      timecode        : 00:00:00:00
  Stream #0:2[0x3](eng): Data: none (tmcd / 0x64636D74) (default)
    Metadata:
      creation_time   : 2022-07-13T14:21:10.000000Z
      handler_name    : Time Code Media Handler
      timecode        : 00:00:00:00
Input #1, lavfi, from 'anullsrc=cl=mono':
  Duration: N/A, start: 0.000000, bitrate: 352 kb/s
  Stream #1:0: Audio: pcm_u8, 44100 Hz, mono, u8, 352 kb/s
Output #0, mov, to 'test.mov':
  Metadata:
    major_brand     : qt
    minor_version   : 537199360
    compatible_brands: qt
    encoder         : Lavf59.27.100
  Stream #0:0(eng): Video: qtrle (rle  / 0x20656C72), argb(progressive), 3840x2160 [SAR 1:1 DAR 16:9], q=2-31, 945725 kb/s, 23.98 fps, 23.98 tbr, 24k tbn (default)
    Metadata:
      creation_time   : 2022-07-13T14:21:10.000000Z
      handler_name    : Apple Video Media Handler
      vendor_id       : appl
      encoder         : Animation
      timecode        : 00:00:00:00
  Stream #0:1: Audio: pcm_u8 (raw  / 0x20776172), 44100 Hz, mono, u8, 352 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #1:0 -> #0:1 (copy)

For some reason, ffmpeg selects mono silence generated by anullsrc, instead of stereo pcm_s16le from source file. Now here is the really weird thing. It only does this for this particular file. If I try to make the file smaller (with -vcodec copy, -acodec copy, -t 5), it works file. And since it's RLE + uncompressed video, it's size is 20 GB.

For those really brave and patient, here is the mov file: ​https://mega.nz/file/8tRQFTZa#K02DK2QSRlm2DTvcwYHBXm4cbDilhhVvu4vTkqZUzI4

[Gyan]

I think I see the issue. That large size likely means the probe waited late, and that added a factor that threw the calc off. Will patch it over the weekend.