Just a quick update for those who could be interested.

"Right arrow" and "Left arrow" allow you to "fast forward/backward" with omxplayer.

To simulate it using fifo to control omxplayer you can :

#Right arrow :
echo -n $'\x1b\x5b\x43' > /tmp/cmd
#Left arrow :
echo -n $'\x1b\x5b\x44' > /tmp/cmd

"forward/backward" work when playing from the local SDCard or a plugged USB Stick, but don't when playing from "http://"

Works with either movies or mp3 (any thing you can feed omxplayer with I guess).

There is many others keys that can control volume, subtitles, etc ... <- See :
https://github.com/huceke/omxplayer/blo ... player.cpp

Example :
z : m_tv_show_info = !m_tv_show_info;
1 : SetSpeed(m_av_clock->OMXPlaySpeed() - 1);
2 : SetSpeed(m_av_clock->OMXPlaySpeed() + 1);
j : m_omx_reader.SetActiveStream(OMXSTREAM_AUDIO, m_omx_reader.GetAudioIndex() - 1);
k : m_omx_reader.SetActiveStream(OMXSTREAM_AUDIO, m_omx_reader.GetAudioIndex() + 1);
etc ...

I have not been able to use "+" and "-" for controlling volume