[FFmpeg-user] ffmpeg choses variable framerate for 1080p video only

[Kosta Vlotis]

i have a script that creates certain video formats. it seems something
is wrong with ffmpeg.

my command line is the following:

ffmpeg -async 2 -i ".\input\%1%2" -f mp4 -c:v libx264 -preset slow -g
60 -level 41 -b:v 12000k -s 1920x1080 -aspect 16:9 -vf
"movie=watermark.png, scale=1920:1080 [logo]; [in] [logo]
overlay=main_w-overlay_w-0:main_h-overlay_h-0 [out]" -af pan="stereo:
c0=c1+c0 : c1=c0+c1" -c:a libvo_aacenc -b:a 128k -ar 48000 -ac 2
-threads 0 -y ".\output\%root_folder_name%\vids\hd\%1_1080p_12000_no_outro.mp4"

the command above produces a video with a variable frame rate even
though the source has a constant frame rate.

running the EXACT same command but changing the resolution to 1280x720
produces the correct result. (copies the frame rate setting from the
source.) the freame rate should come out as 29.970 CFR. Specifying a
framerate by using "-r 29.970" causes ffmpeg to keep the variable
frame rate setting but sets the minimum and maximum frame rate to
29.970.

obviously something is not right.. can anyone help?

Here is the ffmpeg config:

ffmpeg version N-43594-gf0896a6 Copyright (c) 2000-2012 the FFmpeg developers
  built on Aug 15 2012 21:25:48 with gcc 4.7.1 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-pthreads --enable-runt
ime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass -
-enable-libcelt --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-l
ibfreetype --enable-libgsm --enable-libmp3lame --enable-libnut --enable-libopenj
peg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheo
ra --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-li
bvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --ena
ble-zlib
  libavutil      51. 69.100 / 51. 69.100
  libavcodec     54. 52.100 / 54. 52.100
  libavformat    54. 23.101 / 54. 23.101
  libavdevice    54.  2.100 / 54.  2.100
  libavfilter     3.  9.100 /  3.  9.100
  libswscale      2.  1.101 /  2.  1.101
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
Hyper fast Audio and Video encoder
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfi
le}...

Use -h to get full help or, even better, run 'man ffmpeg'