OK, I admit it. I'm an audio geek. Yup.

And one of my really geeky habits is researching new audio and video formats to try to get some insight on where is it all going so I can try to stay ahead of the curve when it comes to offering new and unique services to my clients. So if your into this type of stuff, then keep reading.

While preparing for one of my courses ( Pro Tools for TV and Film ) I found myself digging into one of my favorite applications which is QuickTime Pro. Checking out every function and menu. It goes for a banging ( 29.99 ) and has some very cool features one of which I'd like to share with you. One of which is the topic of this article. Surround Sound Encoding using QuickTime for multimedia formats...

Surround has been around for a while. Actually since about 1940 with Disney's first ever animation Fantasia which employed a 56 speaker mobile traveling system to immerse the audience in sound . Today things have come a long way. Those expensive Dolby hardware encoders are not necessarily a requirement any more for the driven multimedia entrepreneur.

Surround for multimedia is one of the consumers newest crazes for their computers, and gaming devices. Especially those gamers out there. You could be getting your listeners attention with these new and exciting new formats that truly make the audio CD a thing of the past. The first part of learning this process is understanding the file type we'll be using which is called AAC or " Advanced Audio Coding "

The AAC file was developed by the MPEG group that includes Dolby, Fraunhofer (FhG), AT&T, Sony and Nokia. These same companies have also been involved in the development of the audio codec’s MP3 and AC3 (also known as Dolby Digital).

The AAC codec in QuickTime builds upon new, state-of-the art signal processing technology from Dolby Laboratories and brings true variable bit rate (VBR) audio encoding to QuickTime. This format has improved compression, which results in higher quality results with smaller file sizes, support for 48 channels, sampling rates up to 96khz and improved decoding efficiency!

That means right now you could encode a 5.1 mix at 96khz via AAC and your grandma in Kansas could download it and play it on her computer with ease, providing she has a audio card you bought her that supports surround If she has an Xbox 360 or the Playstation 3 she can also play back the 5.1 audio or video file with the included 5.1 audio. A n application like Apple TV will transcode it to the consumer standard Pro Logic format on home theater systems. After you have your six discrete files from your mix, here's what you do.

Assemble the Files

1. Open the AIFF file for the center channel (.C.aiff) with QuickTime Player 7.
2. Open the AIFF file for the left channel (.L.aiff) with QuickTime Player.
3. With the left channel window in front: select the Edit > Select All menu item, and then select the Edit > Copy menu item.
4. Bring the center channel window to the front: go to the beginning of the movie (option-left arrow), and then select the Edit > Add to Movie menu item.
5. Repeat steps 2 - 4 for the remaining right, left surround, right surround, and lfe channels.

Assigning Output Channels

Assigning sound track surround channels At this point, you have a QuickTime movie containing the 6 tracks for 5.1 surround sound. Now it’s time to assign each track to the appropriate output channel: Open the movie properties with the Window > Show Movie Properties menu item. In the Audio Settings tab, assign each track to the appropriate output channel. If you forget the order in which you added the tracks, you can use the resources tab to see which 5.1 channel you are setting the output channel for.

Export QuickTime Movie

• Format: AAC
• Channels: 5.1 (C L R Ls Rs LFE)
• Sample rate: 44.1 kHz
• Target Bit Rate: 96 kbps/chan