Invalid timebase converting videos from Galaxy S3 I have a video that I recorded on my phone and would like to flip horizontally. I am using the following command:

avconv -i 20131117_220136.mp4 -vf "hflip" 20131117_220136.flipped.mp4


I get the following output:

avconv version 0.8.9-4:0.8.9-0ubuntu0.12.04.1, Copyright (c) 2000-2013 the Libav developers
  built on Nov  9 2013 19:12:07 with gcc 4.6.3
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '20131117_220136.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 0
    compatible_brands: isom3gp4
    creation_time   : 2013-11-18 04:35:04
Duration: 00:33:26.03, start: 0.000000, bitrate: 17127 kb/s
    Stream #0.0(eng): Video: h264 (High), yuv420p, 1920x1080, 17000 kb/s, PAR 1:1 DAR 16:9, 30 fps, 90k tbr, 90k tbn, 180k tbc
    Metadata:
      creation_time   : 2013-11-18 04:35:04
    Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16, 124 kb/s
    Metadata:
      creation_time   : 2013-11-18 04:35:04
[buffer @ 0x9a80de0] w:1920 h:1080 pixfmt:yuv420p
[mpeg4 @ 0x9a83200] removing common factors from framerate
[mpeg4 @ 0x9a83200] timebase 1/90000 not supported by MPEG 4 standard, the maximum admitted value for the timebase denominator is 65535
Output #0, mp4, to '20131117_220136.flipped.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 0
    compatible_brands: isom3gp4
    creation_time   : 2013-11-18 04:35:04
    Stream #0.0(eng): Video: mpeg4, yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 90k tbn, 90k tbc
    Metadata:
      creation_time   : 2013-11-18 04:35:04
    Stream #0.1(eng): Audio: [0][0][0][0] / 0x0000, 48000 Hz, stereo, s16, 200 kb/s
    Metadata:
      creation_time   : 2013-11-18 04:35:04
Stream mapping:
  Stream #0:0 -&gt; #0:0 (h264 -&gt; mpeg4)
  Stream #0:1 -&gt; #0:1 (aac -&gt; aac)
Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height


The issue is the timebase 1/90000 not supported by MPEG 4 standard error, I'm assuming. I haven't found anything on it yet.
Specifying the framerate fixes the issue. I.e. adding -r 23.967 to the command.