Videos are showing in Totem but not in some applications

[François Tissandier]

I really don't know where to report this bug ! :)

I have installed Trusty in a virtual machine & on my laptop.
I'm trying to edit subtitles on a video. The video is played without any problem in Totem.
However in the two apps that I tried to edit the subtitles, I only have the sound. I have tried to transcode the video to a totally different codec, and it's the same.

Launching the subtitle editors in a terminal, I see this error :

** Message: don't know how to handle video/mpeg, mpegversion=(int)4, parsed=(boolean)true, systemstream=(boolean)false
Got video info: width=0, height=0, aspect_Ratio=0, frame_rate=0, has_audio=True, has_video=False
Got video duration: 00:09:44.9160000

One of the application tells me that a codec is missing. Which I find weird since totem is playing them fine, and the codecs are nothing exotic (h264 & MPEG4)

Same videos & same apps are working fine with Saucy.