Well, i did some testing with gstreamer and gst-plugins and it turned out that compiling gstreamer and gst-plugins with -O3 results in erratic behaviour at best, mostly it's just not functional at all. -O2 works fine for me. Maybe some more ppl could test it and enter their results as well.
Created attachment 4351 [details] gst-plugins-0.4.1-r1.ebuild [update] Updated ebuild for gst-plugins. Changes are : re-enabeling aalib, dvdread and dvdnav. They compile fine here, disabling their use flags disables them alltogether now for people who do have problems (?). Enabling libdv, and removing it's dvd use flag, libdv has nothing todo with dvd. Putting openquicktime behind the quicktime USE flag. Putting encode flag in for lame. Adding mpeg USE flag for libmpeg2, good for mpeg decoding. Adding jack-audio-connection-kit behind the alsa USE flag because of bug 8217. Added flag-o-matic for reasons mentioned earlier this bug. I also tried compiling the avifile version mentioned in comment #5 of bug 8217, but this did not result in a working avi decoder for me. But with the version coming with gentoo it doesnt work either.
Created attachment 4352 [details] avifile-0.7.7.20020524.ebuild [test ebuild] An ebuild for the avifile package provided by the gstreamer team. Still didn't result in a working avidec for me (windec to be more precise i think). If you try this package, remember to erase all other avifile instances. And adapt the gst-plugins ebuild to not update avifile.
*** Bug 8217 has been marked as a duplicate of this bug. ***
Took the liberty of fixing this myself. New versions are masked for testing now.