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I think I have done something, but I can't tell what exactly... Now, my Ubuntu doesn't want to decode MPEG-4 and H.264 video-files (files extensions .avi .mp4).

vlc still works (of course, it has built-in codecs) but totem and the thumbnailer stopped working.

Here's what I did recently that might be related :

sudo apt-get install libvo-aacenc-dev libx264-dev libtheora-dev librtmp-dev libvorbis-dev libfdk-aac-dev libmp3lame-dev libfaac-dev libpulse-dev libxvidcore-dev

I used them to build libav-toolsfrom GIT. Now libavworks like a charm, and that makes me think that my libx264 is fine (which is, I think, used to decode H.264 and MPEG-4).

I have this error message :

$ ▶ totem video.mp4
** Message: Missing plugin: gstreamer|1.0|totem|H.264 decoder|decoder-video/x-h264, stream-format=(string)avc, alignment=(string)au, level=(string)3.2, profile=(string)main, parsed=(boolean)true (H.264 decoder)

I also tried this and I have plenty of gstreamer-* package installed.

Can you help me ?

share|improve this question
Could you please start totem from the command line and attach possible error messages? – Sylvain Pineau Mar 10 '14 at 16:16
@spineau : done. – MrVaykadji Mar 10 '14 at 16:24
up vote 5 down vote accepted

Try to install gstreamer1.0-libav:

sudo apt-get install gstreamer1.0-libav

Check if libthumbnailer0 is properly installed as well:

sudo apt-get install libthumbnailer0

Then, remove the thumbnails cache :

sudo rm -r ~/.cache/thumbnails

And finally restart Nautilus :

nautilus -q
share|improve this answer
Yep, I figured that out myself thanks to your idea of checking the error-message, but it works only for totem and not the thumbnailer... any ideas? – MrVaykadji Mar 10 '14 at 16:30
even after rebooting your system? – Sylvain Pineau Mar 10 '14 at 16:51
yep, but I found the problem, I edited your answer. Now everything works, thanks for your help ! – MrVaykadji Mar 10 '14 at 16:53

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