Many items showing up on PS3 but not XBox 360

[Adam Kessel <ajkessel gmail com>]

I have both a PS3 and an XBox 360 in my LAN. My entire library appears 
without problem on the PS3, but only a few items show up in the video 
player on XBox 360. There does not appear to be anything systematic 
about which files are showing and which are not on the XBox 360 -- 
nothing consistent about file/media type, path, etc. The XBox 360 is 
only showing a very small fraction of what appears on the PS3. I have 
been using Debian Stable but recently pulled v0.34.0.1-e969e from git 
and rebuilt from source--no difference in what appears. Any suggestions 
for how to troubleshoot?