TiVo sample not auto-detected

[Carl Eugen Hoyos]

The following sample can be decoded when forcing the ty demuxer, is not autodetected. Auto-detection works fine with MPlayer, vlc detects the suffix.
​http://samples.ffmpeg.org/TiVo/test-dtivo-junkskip.ty+

$ ffmpeg -i test-dtivo-junkskip.ty+
ffmpeg version N-88567-ga6a6935 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 6.3.0 (GCC)
  configuration: --enable-gpl --cc=/usr/local/gcc-6.3.0/bin/gcc
  libavutil      56.  0.100 / 56.  0.100
  libavcodec     58.  1.100 / 58.  1.100
  libavformat    58.  2.100 / 58.  2.100
  libavdevice    58.  0.100 / 58.  0.100
  libavfilter     7.  0.101 /  7.  0.101
  libswscale      5.  0.101 /  5.  0.101
  libswresample   3.  0.101 /  3.  0.101
  libpostproc    55.  0.100 / 55.  0.100
[mpeg @ 0x2a6a240] Format mpeg detected only with low score of 25, misdetection possible!
Input #0, mpeg, from 'test-dtivo-junkskip.ty+':
  Duration: 00:00:14.83, start: 3554.749044, bitrate: 2827 kb/s
    Stream #0:0[0x1c0]: Audio: mp2, 48000 Hz, stereo, s16p, 192 kb/s
At least one output file must be specified

$ ffmpeg -f ty -i test-dtivo-junkskip.ty+
ffmpeg version N-88567-ga6a6935 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 6.3.0 (GCC)
  configuration: --enable-gpl
  libavutil      56.  0.100 / 56.  0.100
  libavcodec     58.  1.100 / 58.  1.100
  libavformat    58.  2.100 / 58.  2.100
  libavdevice    58.  0.100 / 58.  0.100
  libavfilter     7.  0.101 /  7.  0.101
  libswscale      5.  0.101 /  5.  0.101
  libswresample   3.  0.101 /  3.  0.101
  libpostproc    55.  0.100 / 55.  0.100
[mpeg2video @ 0x3a977e0] Invalid frame dimensions 0x0.
    Last message repeated 28 times
Input #0, ty, from 'test-dtivo-junkskip.ty+':
  Duration: N/A, start: 3554.749044, bitrate: N/A
    Stream #0:0: Video: mpeg2video (Main), yuv420p(tv, top first), 480x480 [SAR 4:3 DAR 4:3], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
    Stream #0:1: Audio: mp2, 48000 Hz, stereo, s16p, 192 kb/s
At least one output file must be specified

[Elon Musk]

Now if you increase probe size it works.