[FFmpeg-user] Assumefps() equivalent in FFMPEG

[Eugene Gekhter]

I have a 50fps progressive scan file that I need to playback at 18fps - no
dropped frames.

AVIsynth has a function assumefps(18) which when used in conjunction with a
video file and opened in FFMPEG, looks like:

ffprobe version N-56648-g65bf9a4 Copyright (c) 2007-2013 the FFmpeg
developers
  built on Sep 25 2013 03:39:09 with gcc 4.8.1 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads
--enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r
--enable-gnutls --enable-iconv --enable-libass --enable-libbluray
--enable-libcaca --enable-libfreetype --enable-libgsm --enable-libilbc
--enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus
--enable-librtmp --enable-libschroedinger --enable-libsoxr
--enable-libspeex --enable-libtheora --enable-libtwolame
--enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc
--enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264
--enable-libxavs --enable-libxvid --enable-zlib
  libavutil      52. 46.100 / 52. 46.100
  libavcodec     55. 33.100 / 55. 33.100
  libavformat    55. 18.102 / 55. 18.102
  libavdevice    55.  3.100 / 55.  3.100
  libavfilter     3. 87.100 /  3. 87.100
  libswscale      2.  5.100 /  2.  5.100
  libswresample   0. 17.103 /  0. 17.103
  libpostproc    52.  3.100 / 52.  3.100
Input #0, avisynth, from
'E:\VirtualDub-1.9.11\16653_McCartney-S8mm_C-01.avs':
  Duration: 00:11:21.72, start: 0.000000, bitrate: 0 kb/s
    Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 1920x1080, *18
fps, 18 tbr, 18 tbn, 18 tbc*
    Stream #0:1: Audio: pcm_f32le, 48000 Hz, 2 channels, flt, 3072 kb/s


I try and accomplish the same result of 18 fps, 18 tbr, 18 tbn, and 18 tbc
directly in ffmpeg with:
-r 18 -i "<SourceFileName>" -y -vcodec copy  -acodec copy
 "<OutputPath><OutputFileName>.mov"

but the output is  Stream #0:0(eng): Video: v210 (v210 / 0x30313276),
yuv422p1
1, 995328 kb/s, 50 fps, 18432 tbn, 18 tbc (default)

Any tricks on how to accomplish the uniform 18 timebase?

Thanks,

*Eugene Gekhter* / CEO

(847) 272-8207/ egekhter at pixcel.com
*Pixcel* Office: (800) 557-3508
3336 Commercial Ave. / Northbrook, IL 60062
http://www.pixcel.com