Videomaker – Learn video production and editing, camera reviews › Forums › General › Video and Film Discussion › HOW do I get my video in MPEG-4 audio AAC › Render as Main Concept AVC,
Render as Main Concept AVC, AAC (*.mp4). Check you custom settings for frame rate and resolution and check the audio tab to make sure the audio is AAC. It will probly have a template selected that say's "Youtube" or something but you over ride those settings in the custom set up.
I don't have the studio 12 but I have Vegas Movie studio 10 and Vegas pro 12 and the setting is in both of them so it should be in the Vegas Movie studio platinum 12 as well. That's kind of a web standard. You might get away with higher bit rates for the festival though.
Hope that helps