I would like to know if it is planned to add Gmusicbrowser playing audio stream from video file like avi, ogv, mkv?
Gmusicbrowser uses Gstreamer to play audio file, so it will be possible to ask gstreamer to play other type of media file, isn't it?

It's not planned.
Gmusicbrowser doesn't use gstreamer for reading tags/audio properties for various reasons :
- historical reasons
- from what I read using gstreamer was rather slow to scan a library, it's more made for playing. Maybe things have changed since
- stability, mostly due the perl-glib bug with foreign threads
- to have more control on the tags, though I'm admittedly not very familiar with that part of gstreamer
- being able to not depend on gstreamer at all, using mplayer to play
So I would have to write parsers for video files, though they could maybe use existing libraries for most of the work.

I ask you this question because I have a lot of videos of audio music in my music library and I don't think I'm the only one in this case.


Well, using mplayer maybe makes this easier.

However, if you don't want the video I think a better alternative would be to just extract the audio. I'm not sure if metadata from video files could be used for that purpose.