I’m attempting to reinstate multichannel audio. Generally, 720p versions will have AAC and only the 1080p versions will have AC3 if needed. Basically, AC3 = More than 2 channels. Of course, it will be of very high quality just like my AAC encodes.
Please leave a comment if you like/care about surround sound (I need to know if it’s worth doing) and if there are any compatibility issues.