Seek location in a youtube/stream URL?

I’ve been messing with the mopidy-youtube plugin and realized that there seems to be no seek support. I’d like to add it, so I’ve been trying to understand how the core works. I figure it must be using Gstreamer for the seeking, so I decided to validate that it could seek on a youtube stream url (just to make sure the mopify-youtube wasn’t opting out of the default seeking mechanism). So I tried this url:

https://r4—sn-nx5e6n7z.googlevideo.com/videoplayback?id=966736d55fb306ad&itag=141&source=youtube&requiressl=yes&mn=sn-nx5e6n7z&mm=31&ms=au&mv=m&pl=18&ratebypass=yes&mime=audio/mp4&gir=yes&clen=6889146&lmt=1432424385951093&dur=216.061&signature=2FE71E8B27AA81B5E09A0271AD98028EC3273BBA.8965E0B83E088C3629DD2354102482E5BC6CA6B2&sver=3&mt=1436760694&fexp=901816,9406000,9407052,9407465,9407641,9408142,9408420,9408710,9409098,9409170,9412774,9414618,9414824,9414873,9416126,9416223,9416285&upn=gf9LAvp0p_I&key=dg_yt0&ip=50.149.111.228&ipbits=0&expire=1436782341&sparams=ip,ipbits,expire,id,itag,source,requiressl,mn,mm,ms,mv,pl,ratebypass,mime,gir,clen,lmt,dur

I’ve found that I can’t seek that, either, which I suppose means there’s no backend support for seeking from a url in Gstreamer? I can seek no problem with that URL in mplayer using ffmpeg, so I know the stream supports this. Any help or pointers on this would be great, I’d love to start contributing :smile:

Is this something that gstreamer/mopidy already support, and I may just have the wrong libs on my system to handle seeking of AAC streams? Seems like mopidy-stream songs don’t seek for me either, so maybe it’s my own setup?