This is the output of oggdec:
oggdec
OggDec 1.0 (Tremor)
Usage: oggdec [flags] file1.ogg [file2.ogg … fileN.ogg]
Supported flags:
–quiet, -Q Quiet mode. No console output.
–help, -h Produce this help message.
–version, -v Print out version number.
–raw, -R Raw (headerless) output.
–output, -o Output to given filename. May only be used
if there is only one input file
This is installed (all with vorbis in name thats installed):
ivorbis-tools 1.0-2 1.0-2 Tools to allow you to play, encode, and manage Ogg Vorbis files. This version is hacked to use the Tremor integer decoder. delete
libvorbis 1.1.2-3 1.1.2-3 Ogg Vorbis compressed audio format. delete
libvorbisidec cvs-20050221-2 cvs-20050221-2 libvorbisidec is the integer-only ogg decoder library, AKA Tremor delete
The normal vorbis-tools is also listed in the package list but not installed. As it should if I understand you right.