After Effects CC 2014 (13.0) does not include exporters for creating H.264, MPEG-2, and WMV videos directly from the render queue. To create videos in these formats, you should use Adobe Media Encoder.
You can still import videos in these formats into After Effects.
You have two primary options for using Adobe Media Encoder with After Effects to create videos in H.264, MPEG-2, and WMV formats.
The fastest way to create videos in these formats using Adobe Media Encoder with After Effects is to use the After Effects render queue to export a losslessly encoded master file (e.g., using the PNG video codec in a QuickTime .mov container file) to a watch folder that Adobe Media Encoder monitors. You can assign encoding presets to a watch folder in Adobe Media Encoder so that it automatically encodes using whichever settings you have specified.
One advantage of using this method is that it uses After Effects performance features for rendering (such as GPU acceleration and multiprocessing where applicable) and Adobe Media Encoder performance features for encoding (such as parallel encoding). The disadvantage of using this method is that it occupies the main After Effects application for the entire rendering operation, during which time you can’t use After Effects for anything else.
Another method to create videos in these formats using Adobe Media Encoder with After Effects is to directly add the composition from After Effects to the Adobe Media Encoder queue.
This method has the advantage of allowing you to continue working in After Effects while the rendering and encoding takes place, since the rendering is performed by a background instance of After Effects. The rendering phase may be slower in some cases, compared with using the After Effects render queue, because the headless version of After Effects rendering in the background does not have access to GPU acceleration and multiprocessing features.
The reason the H.264, MPEG-2, and WMV exporters were removed from the After Effects render queue is simple: Maintaining these exporters in After Effects took quite a lot of work, and fixing several significant bugs in these exporters would take even more work. Work would have subtracted from other resources.
Since Adobe Media Encoder already had superior H.264, MPEG-2, and WMV exporting capabilities, it was more prudent to rely on Adobe Media Encoder for export of these formats, allowing the After Effects team to focus efforts on animation, motion graphics, compositing, and digital imaging features—which core areas for After Effects.
One thing that makes Adobe Media Encoder so much better than After Effects for creation of files in final delivery formats is its Preset Browser and easy-to-use system for creating, saving, sharing, and applying encoding presets. Another is the assortment of features in the Effects tab with which you can automatically add watermarks, timecode overlays, et cetera.
If you still need to be able to create videos in these formats from the After Effects render queue for some reason, you can still do so by leaving After Effects CC (12.2.1) installed alongside After Effects CC 2014 (13.0) and using the previous version for these specific output tasks.
For more details, see this blog post.