Para fazer transmissões de evento ao vivo eu estou utilizando o gstreamer. No Fedora 20 ele com a versão libshout 2.2.2 e só a partir da versão 2.3 que o libshout passa a ter suporte a webm. Então precisei recompilar os pacotes gstreamer-plugins-bad-0.10 gstreamer-plugins-good libshout. A seguir as instruções de como fiz:

yumdownloader --source libshout
sudo yum-builddep libshout-2.2.2-10.fc20.src.rpm --nogpgcheck
rpm -ivh libshout-2.2.2-10.fc20.src.rpm
sed -i '42d' ~/rpmbuild/SPECS/libshout.spec
sed -i '10d' ~/rpmbuild/SPECS/libshout.spec
sed -i 's/2.2.2/2.3.1/g' ~/rpmbuild/SPECS/libshout.spec
wget http://downloads.us.xiph.org/releases/libshout/libshout-2.3.1.tar.gz
mv libshout-2.3.1.tar.gz ~/rpmbuild/SOURCES/
cd ~/rpmbuild/SPECS
rpmbuild -ba libshout.spec
cd ~/rpmbuild/RPMS/x86_64/
sudo rpm -Uvh libshout-*

yumdownloader --source gstreamer-plugins-good
sudo yum-builddep gstreamer-plugins-good-0.10.31-10.fc20.src.rpm --nogpgcheck
rpmbuild --rebuild gstreamer-plugins-good-0.10.31-10.fc20.src.rpm
cd ~/rpmbuild/RPMS/x86_64/
sudo rpm -Uvh gstreamer-plugins-good-0.10.31-10.fc20.x86_64.rpm --force

yumdownloader --source gstreamer-plugins-bad
sudo yum-builddep gstreamer-plugins-bad-0.10.23-5.fc20.src.rpm --nogpgcheck
rpmbuild --rebuild gstreamer-plugins-bad-0.10.23-5.fc20.src.rpm
cd ~/rpmbuild/RPMS/x86_64/
sudo rpm -Uvh gstreamer-plugins-bad-0.10.23-5.fc20.x86_64.rpm --force