> ffmpeg -i wrongduration.avi
[avi @ 0x7fedb1000000] non-interleaved AVI
Guessed Channel Layout for  Input Stream #0.1 : mono
Input #0, avi, from 'test.avi':
  Metadata:
    encoder         : Lavf55.33.100
  Duration: 00:00:01.00, start: 0.000000, bitrate: 43628 kb/s
    Stream #0:0: Video: mpeg4 (Simple Profile) (FMP4 / 0x34504D46), yuv420p, 1024x640 [SAR 1:1 DAR 8:5], 1 fps, 1 tbr, 1 tbn, 1 tbc
    Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 1 channels, s16, 705 kb/s



> ffmpeg -i rightduration.avi
Guessed Channel Layout for  Input Stream #0.1 : mono
Input #0, avi, from 'test (2).avi':
  Metadata:
    encoder         : Lavf55.33.100
  Duration: 00:01:02.00, start: 0.000000, bitrate: 755 kb/s
    Stream #0:0: Video: mpeg4 (Simple Profile) (FMP4 / 0x34504D46), yuv420p, 1024x640 [SAR 1:1 DAR 8:5], 57 kb/s, 1 fps, 1 tbr, 1 tbn, 1 tbc
    Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 1 channels, s16, 705 kb/s