While this doesn't answer your question precisely, this may help prevent frustration attempting to export all photos and all videos simultaneously.

Create a smart album in Aperture or in iPhoto setting conditions to find all the video like in the image below:

Its just not clear what video formats are compatible with Aperture or iPhoto, so adding every format you can think of to these conditions won't hurt anything.

Once the smart album is created, you can select all the videos in the album and export them in one step.

Alternatives

(At this point I just can't justify $140 for Lightroom, or commit to their CC to get it...)

darktable

Alternatively, for an application more powerful than iPhoto, and holds its own against Lightroom or Aperture, I've discovered darktable, which

"is an open source photography workflow application and RAW developer. A virtual lighttable and darkroom for photographers. It manages your digital negatives in a database, lets you view them through a zoomable lighttable and enables you to develop raw images and enhance them."

darktable can be installed manually, but is also maintained as a port using MacPorts, if you prefer to use package management. I've included step by step instructions for installing MacPorts and darktable below.

GIMP

An extremely powerful alternative to editing photos is using the GIMP. The GIMP can be installed manually, or built from source using MacPorts. I've included instructions below on how to install the GIMP using MacPorts. If you know Adobe Photoshop well, you may want to demo using GIMPshop, which very cleverly and conveniently reconstructs the look and feel of the GIMP to appear and behave nearly just like Photoshop... and its all for free.

MacPorts

MacPorts is a robust, stable, mature and easy to use package management solution, for OS X. It is modeled after FreeBSD's ports system, which has been adopted as the basis of NetBSD's pkgsrc. I highly recommend MacPorts.

install Xcode 5.1.1

MacPorts requires an appropriate version of xcode; xcode_5.1.1.dmg is the most recent version for Mavericks (after registerring for a free developer account, and logging into developer.apple.com, that link will begin your xcode download). Once the download completes, lets just do it all in /Applications/Utilities/Terminal.app (don't be afraid of the terminal!):

 goodytx@stack:~$ 
 goodytx@stack:~$ hdiutil attach -quiet -noverify -nobrowse -noautoopen ~/Downloads/xcode_5.1.1.dmg
 goodytx@stack:~$ cp -npR /Volumes/Xcode/Xcode.app /Applications/
 goodytx@stack:~$ hdiutil detach -quiet /Volumes/Xcode
 goodytx@stack:~$ open -g /Applications/Xcode.app; sleep 8
 goodytx@stack:~$ 
 goodytx@stack:~$ killall Xcode.app

install MacPorts

Get to know MacPorts

 goodytx@stack:~$ 
 goodytx@stack:~$ 
 goodytx@stack:~$ curl -Ok https://distfiles.macports.org/MacPorts/MacPorts-2.2.1.tar.bz2
 goodytx@stack:~$ tar xf MacPorts-2.2.1.tar.bz2
 goodytx@stack:~$ cd MacPorts-2.2.1
 goodytx@stack:~$ ./configure
 goodytx@stack:~$ make
 goodytx@stack:~$ sudo make install     # *not war!*
 goodytx@stack:~$ cd ..
 goodytx@stack:~$ rm -rf Macports-*
 goodytx@stack:~$ sudo /opt/local/bin/port -v selfupdate
 goodytx@stack:~$ diskutil quiet repairPermissions /
 goodytx@stack:~$ 
 goodytx@stack:~$ 

add MacPorts to your $PATH:

 goodytx@stack:~$ 
 goodytx@stack:~$ export PATH=/opt/local/bin:/opt/local/sbin:$PATH
 goodytx@stack:~$ export MANPATH=/opt/local/share/ man:$MANPATH
 goodytx@stack:~$ 

install darktable and the gimp

 goodytx@stack:~$
 goodytx@stack:~$ 
 goodytx@stack:~$ port info darktable
 darktable @1.1.2_5 (graphics)
 Variants:             gcc44, gcc45, gcc46, gcc47, gnome_keyring, quartz, universal, [+]x11

 Description:          Darktable is a virtual lighttable and darkroom for photographers: it manages your digital
                       negatives in a database and lets you view them through a zoomable lighttable. It also
                       enables you to develop raw images and enhance them.
 Homepage:             http://www.darktable.org/

 Build Dependencies:   cmake, pkgconfig
 Library Dependencies: cairo, curl, dbus-glib, exiv2, gettext, glib2, gtk2, gtk-engines2, jpeg, json-glib, lcms2,
                       lensfun, libglade2, libgphoto2, libpng, librsvg,           libxml2, openexr, sqlite3, tiff, zlib
 Platforms:            darwin
 License:              GPL-3+
 Maintainers:          julians37@gmail.com
 goodytx@stack:~$
 goodytx@stack:~$ port info gimp
 gimp @2.8.10 (graphics)
 Variants:             animation, gmic, quartz

 Description:          This is a META port for the GNU Image Manipulation Program (GIMP) which includes support
                       for icns, JP2000 and RAW formats, content-aware rescaling, Gutenprint and scanner frontends
                       and, optionally, an animation tool (the GIMP Animation Package) and an image processing and
                       scientific visualization tool (GREYC's Magic Image Converter).
 Homepage:             http://www.gimp.org/

 Library Dependencies: icns-gimp, gimp-jp2, gimp-lqr-plugin, gtk-nodoka-engine, gutenprint, ufraw, xsane, gimp-app
 Platforms:            darwin
 License:              none
 Maintainers:          devans@macports.org
 goodytx@stack:~$ 
 goodytx@stack:~$ 
 goodytx@stack:~$ # the port info commands above are unnecessary, you only need one command to install both ports:
 goodytx@stack:~$ 
 goodytx@stack:~$ sudo port -vsc install darktable gimp

migrating from Aperture to darktable

That's really all there is to it. If you can follow a recipe to bake a cake, you can do this too. And you can keep all your ports updated to quite simply with:

 goodytx@stack:~$ 
 goodytx@stack:~$ sudo port -vsc selfupdate
 goodytx@stack:~$ sudo port -vsc upgrade installed

MacPorts will not interfere with the use of OS X, Aperture, iPhoto, Lightroom, nor with any other software. It keeps everything it installs in its /opt directory (and any full gui applications it builds in /Applications/MacPorts/ ).

more free software available

searching macports for "photo" returns 17 more ports besides darktable, while searching for "image" returns a whopping 260 more ports of image utilities

 goodytx@stack:~$ port search photo
 goodytx@stack:~$ # too much to list here
 goodytx@stack:~$ port search image
 goodytx@stack:~$ # way too much to list here

If for whatever reason you are unsatisfied and/or need to remove MacPorts:

to completely uninstall MacPorts

 goodytx@stack:~$ 
 goodytx@stack:~$ sudo port -dfp uninstall --follow-dependencies installed
 goodytx@stack:~$ sudo port -dfp uninstall all
 goodytx@stack:~$ sudo rm -rf /opt/local  
 goodytx@stack:~$ sudo rm -rf /Library/Tcl/macports*
 goodytx@stack:~$ 
 goodytx@stack:~$ # if you also want to delete any stand-alone gui applications you've built with macports, then there is one more command:
 goodytx@stack:~$ 
 goodytx@stack:~$ sudo rm -rf /Applications/MacPorts
 goodytx@stack:~$ 

In short, you (often) need to include the argument -pix_fmt yuv420p when using ffmpeg to generate H.264 content for Apple software/devices, and a bunch of other decoders that don't handle yuv444p.

# ffmpeg -i input.avi -pix_fmt yuv420p output.mp4

This is not mentioned in the output when using the defaults, but can be found in their Encode/H.264 guide.

It turns out that ffmpeg have chosen a default pixel format of yuv444p for libx264 encoding (under some circumstances), which is not compatible with Apple's software/hardware H.264 decoders (and perhaps not very widely compatible in general?). Unfortunately this seems unlikely to change, and there's no warning about it, so just something you have to know if using ffmpeg to make H.264 files.

As far as I can tell, if converting a video that's already using yuv420p it'll maintain that, but if converting from something a bit more exotic (e.g. images or a GIF or whatever) the pixel format must be specified for general Apple compatibility.