[FFmpeg-user] -f mkv cannot be used, why?

[Christoph Gerstbauer]

Hello,

why does FFmpeg me not allow to use the -f mkv syntax when generating an 
mkv?
It does its job only when I leave the -f mkv option and set just the 
fileending *.mkv as usual.

Is this a bug maybe?
When doing it with -f mxf or -f mov it works. Why not with mkv?

Best Regards
chris



C:\Users\gersti>ffmpeg -i I:\networksample\55974_64286.avi -map 0:v -map 
0:a -c:v ffv1 -level 3 -g 1 -slices 16 -slicecrc 1 -s 720x608 -r 25 
-pix_fmt yuv422p -aspect 4:3 -c:a pcm_s24le -ar 48000 -ac 8 -tim
ecode 10:00:00:00 -f mkv I:\networksample\55974_64286.mkv
ffmpeg version N-78313-g6632802 Copyright (c) 2000-2016 the FFmpeg 
developers
   built with gcc 5.3.0 (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-libbs2b
  --enable-libcaca --enable-libdcadec --enable-libfreetype 
--enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug 
--enable-libmp3lame --enable-libopencore-amrnb 
--enable-libopencore-amrwb --enable-libopenjpe
g --enable-libopus --enable-librtmp --enable-libschroedinger 
--enable-libsoxr --enable-libspeex --enable-libtheora 
--enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc 
--enable-libvorbis --enable-libvpx --enab
le-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 
--enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma 
--enable-decklink --enable-zlib
   libavutil      55. 17.100 / 55. 17.100
   libavcodec     57. 24.101 / 57. 24.101
   libavformat    57. 24.100 / 57. 24.100
   libavdevice    57.  0.101 / 57.  0.101
   libavfilter     6. 28.100 /  6. 28.100
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.101 /  2.  0.101
   libpostproc    54.  0.100 / 54.  0.100
Input #0, avi, from 'I:\networksample\55974_64286.avi':
   Metadata:
     encoder         : Lavf57.20.100
   Duration: 02:11:17.32, start: 0.000000, bitrate: 81299 kb/s
     Stream #0:0: Video: huffyuv (HFYU / 0x55594648), yuv422p, 720x608, 
72031 kb/s, SAR 89:61 DAR 4005:2318, 25 fps, 25 tbr, 25 tbn, 25 tbc
     Stream #0:1: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 48000 Hz, 
7.1, s32 (24 bit), 9216 kb/s
[NULL @ 000000ca6b53d440] Requested output format 'mkv' is not a 
suitable output format
I:\networksample\55974_64286.mkv: Invalid argument