Input option -loop 1 broken

[Carl Eugen Hoyos]

The input option -loop 1 is broken since b3fd2b17

$ ffmpeg -loop 1 -i fate-suite/png1/lena-rgb24.png -f null -
ffmpeg version N-66454-ge113692 Copyright (c) 2000-2014 the FFmpeg developers
  built on Sep 25 2014 19:02:01 with gcc 4.7 (SUSE Linux)
  configuration: --enable-gpl
  libavutil      54.  7.101 / 54.  7.101
  libavcodec     56.  1.101 / 56.  1.101
  libavformat    56.  5.100 / 56.  5.100
  libavdevice    56.  1.100 / 56.  1.100
  libavfilter     5.  1.102 /  5.  1.102
  libswscale      3.  1.100 /  3.  1.100
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  1.100 / 53.  1.100
Input #0, png_pipe, from 'fate-suite/png1/lena-rgb24.png':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: png, rgb24, 128x128 [SAR 72:72 DAR 1:1], 25 tbr, 25 tbn, 25 tbc
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf56.5.100
    Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 128x128 [SAR 72:72 DAR 1:1], q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
    Metadata:
      encoder         : Lavc56.1.101 rawvideo
Stream mapping:
  Stream #0:0 -> #0:0 (png (native) -> rawvideo (native))
Press [q] to stop, [?] for help
[null @ 0x3431d60] Encoder did not produce proper pts, making some up.
frame=    1 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown

Related to tickets #3901 and #3948

[Michael Niedermayer]

Fixed in 684508ba15ca15d5d43f67bbed483ce5b6617f10