converting or rendering video to AVC HD-Mpeg4

I am editing some files that are in AVC HD- Mpeg4 format. I need to export them out to the exact same format. But my older Mac can't seem to create that format. I have scoured the computer for that format. I can find Mpeg 4 but it doesn't meet all the other specs of the original format. How can I either render out to the AVC HD-Mpeg format or convert a file to the format?
Thanks