This is my first experience with yum. After reading the unofficial Fedora FAQ, I decided to try the suggestion to get Rhythmbox to play MP3's. Up to this point Rhythmbox will play all my ogg files. After letting yum update all the headers, I typed the following as per the FAQ:

yum install gstreamer-plugins-mp3

which seemed to work all right. Then I typed:

gst-register-0.8

I then fired up rhythmbox to test on some sample mp3's. Now Rhythmbox won't play any audio files at all with the following error:

Error: could not start pipeline playing

Thinking that the yum-installed gstreamer-plugins-mp3 caused the problem, I then tried:

yum remove gstreamer-plugins-mp3

Then I started up rhythmbox and tried to play any ogg audio file...now I still get the error:

Error: could not start pipeline playing

What am I missing?

Upon closer inspection, launching rhythmbox from a terminal window resulted in the following error:

(rhythmbox:2523): GStreamer-CRITICAL **: file gstpad.c: line 3613 (gst_pad_template_new): assertion `caps != NULL' failed

(rhythmbox:2523): GStreamer-CRITICAL **: file gstelementfactory.c: line 349 (__gst_element_factory_add_pad_template): assertion `templ != NULL' failed

I then checked the version of gstreamer with rpm -q and discovered that yum had updated gstreamer to gstreamer-0.8.3-2 from the gstreamer-0.8.1-1 original that came with the stock FC2 install. I removed the gstreamer-0.8.3-2 with rpm -e, reinstalled the stock gstreamer-0.8.1-1, fired up rhthymbox and presto! rhythmbox now played ogg files again. Since the vast bulk of my audio files are ogg files, I'll settle for playing mp3's in XMMS. I seem to have the habit of answering my own questions. %-)

What is in your /etc/yum.conf? Don't add any repositories which upgrade Fedora Core unofficially or which conflict with Fedora Core and its Updates.

There's a flawlessly working gstreamer-plugins-mp3 package at http://rpm.livna.org, which installs cleanly and doesn't need anybody to run gst-register manually or something like that. With it, rhythmbox and sound-juicer just work.

After reading your post, I discovered my first mistake was blindly following the Unofficial Fedora FAQ's suggestion to use their yum.conf as is. I'm glad I just renamed my original yum.conf to yum.bak. I put the stock FC2 yum.conf back in place and edited it as per livna and fedora.us suggestions. Thanks for the heads up!!