[FFmpeg-user] maktroska and -ss

[kqt4at5v at gmail.com]

I did a little recording with
ffmpeg -y -f alsa -ac 2 -i hw:0,0 -f x11grab -r 30000/1001 -s 714x404 -i 
:0.0+435,462 -acodec ac3 -ab 128k -vcodec libx264 -preset ultrafast -t 600 
"file.mkv"
When I try to edit with "ffplay -ss 13 -i file.mkv" it does not jump to the 
right time
I do not seem to be able to jump to a specific second
I am using packages from Fedora 18
What have I screwed up

ffmpeg version 1.0.5 Copyright (c) 2000-2012 the FFmpeg developers
   built on Mar 10 2013 12:20:02 with gcc 4.7.2 (GCC) 20121109 (Red Hat 4.7.2-8)
   configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg 
--incdir=/usr/include/ffmpeg --libdir=/usr/lib --mandir=/usr/share/man 
--arch=i686 --optflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions 
-fstack-protector --param=ssp-buffer-size=4 -m32 -march=i686 -mtune=atom 
-fasynchronous-unwind-tables' --enable-bzlib --disable-crystalhd 
--enable-frei0r --enable-gnutls --enable-libass --enable-libcdio 
--enable-libcelt --enable-libdc1394 --disable-indev=jack --enable-libfreetype 
--enable-libgsm --enable-libmp3lame --enable-openal --enable-libopencv 
--enable-libopenjpeg --enable-libopus --enable-libpulse 
--enable-libschroedinger --enable-libspeex --enable-libtheora 
--enable-libvorbis --enable-libv4l2 --enable-libvpx --enable-libx264 
--enable-libxvid --enable-x11grab --enable-avfilter --enable-postproc 
--enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug 
--disable-stripping --shlibdir=/usr/lib --cpu=i686 --enable-runtime-cpudetect
   libavutil      51. 73.101 / 51. 73.101
   libavcodec     54. 59.100 / 54. 59.100
   libavformat    54. 29.104 / 54. 29.104
   libavdevice    54.  2.101 / 54.  2.101
   libavfilter     3. 17.100 /  3. 17.100
   libswscale      2.  1.101 /  2.  1.101
   libswresample   0. 15.100 /  0. 15.100
   libpostproc    52.  0.100 / 52.  0.100


Richard