The subject says it all.

Seeking enlightenment here.

The multimedia menu will only appear when you have packages that belong to that category.  Since you provide no additional info about anything I am going to assume that you performed a clean checkout from the svn repository.  This provides you with the core set of packages, which are pages needed for proper functionality of devices.  In order to obtain all the extra/additional packages available you have to run `make package/symlinks'  to checkout https://svn.openwrt.org/openwrt/packages into your trunk/feeds/ folder and symlink every package contained therein to trunk/package/   After running that command a simple `make menuconfig' will cause buildroot-ng to parse all the new package information.

Sorry about my noble but foolish desire to be terse.

A better subject for this thread would have been, "Why aren't there any menuconfig options for video anymore?"

I want to use the pwc modules with v4l, and there don't seem to be any menuconfig options for either of them.

There is an older thread about this; the pwc modules used to show up in the menus but didn't build.  I found out to "make kernel_menuconfig" and turn it on there, and all was well.

But now I upgraded to the latest SVN trunk and things seem hosed.  If I turn things on in the kernel configs the modules get built, but they aren't packaged up.

Hopefully someday all the magic behind these things will be documented.  . . . .