QT 7 and Surround Sound Creation?

Question

I've searched around but been unable to find any documentation on how to create Multichannel AAC in QT. I did find a complicated method mentioned on the Handbreak forum, but nothing at Apple. And it seems to be completely ignored on this board.
I did use Compressor2 to import and create a 5.1 AAC but apparently it didn't assign the channels on the output file. The only way I've found so far is the open every track, copy + add, and assign channels as you go Handbreak method. And would this adaptor allow 5.1 QT output from an older Mac like my TiBook?
So where is Apple hiding this documentation that a few hours of searching fails to find?
TiBook 667, FW800 Dual 1.25   Mac OS X (10.4.6)  

Answer 1

So where is Apple hiding this documentation that a few hours of searching fails to find?
A very good quesion and one which peaked my interest. Decided to see what I could find out. Quickly learned the results of my searches on the Internet tended to end up long on generalities and short on specifics. Ended up just giving up and blundering around in the dark on my own. Rather than attempting to address the specific issues you addressed (most/many of which remain unanswered), will try to simply recount my activities since Friday.
Since AIFF files were specifically mentioned, my first attempts to generate a "multichannel" audio movie were directed in that direction. However, since I lack the required hardware to generate, record, and/or mix down descrete channels on my own, I figured it best to use the audio from a DVD. Luckily, owning to the "near destruction" of my wife's "Sabrina" DVD by small visiting hands in our household, I happened to still have a copy of the image file on my HD. And this is where I encountered my first problem.
While there are quite a few applications and utilities available that wil demux the VOB file, it turns out that many/most (e.g., QT, MPEG2 Works, MPEG Streamclip, etc.) seem to perform a mixdown to two channels by default. (If anyone knows of a setting or preference that will defeat this action, plaese et me know. In the case of QT and MPEG2 Works, the mixdown seems to be limited to L/R stereo while MPEG Streamclip allows selection of tracks (e.g., L/R, C/C, Ls/Rs, LFE Screen, etc.) but not the selection of individual tracks. Spent much of Friday night and the wee hours of Saturday morning attempting to create "clean" discrete single channels of audio and pairs of channels that contained the desired, unrepeated, unmixed, audio in mono and 2-channel AIFF files. Finally decided this was more work than it was worth and elected to go with AC3 files instead.
Ouch! Seems there have been changes to the A-Pack utilitiy. Haven't used it in years and didn't realized A-Pack 2 no longer has the ability to decode to a single "multichannel" audio file. Was shocked when my first attempt ended up with two discrete audio channels that were once again "mixed down" versions. Luckily, I finally noticed the setting that allows the user to save in either mixdown discrete or all channel discrete files. Once I had the discrete files on the hard drive, it was a simple matter to convert the VOB video data to DV video which could then be opened and, as Thomas put it, "open, copy, add, and assign" the audio files as needed. Actually, this was probably the fastest part of my work flow up to this point, so I saw nothing wrong with this approach.
Don't know if it makes a difference, but having downloaded an Apple movie trailer, looked it over, and simply added the discrete designated audio files in the same purpose order as used in the trailer example. I then converted the file to an H.264/AAC file of "iPod level" quality which could be used for Internet distribution of family media files later. (I.e., 320 x 176, 9:16, 400 kbps video data rate with 44.1 sampled C,L,R,Ls,Rs,LEF audio at 224 kbps.) Overall data rate was in the 640-660 kbps range which, of course would be suitable for 768 kbps ISP connestions. In any event, I was "on top of the world" when the converted file was mixed down to a single audio track with all channels still maintaining their designated assignments.
Of course, it was about this time that I read Thomas's comment about Compressor 2 and channel designations. This got me to worrying also, so I went through my "test" file and made an "aural" check by turing off all audio channels and comparing the sound-speaker correlation by turning on each channel one-at-a-time. All seems well except for the LEF channel which seemed empty. (But more on that later.) In any case, I figured that many out there would complain that this was not the best way to go about making any sort of a comprehensive check -- and I must agree. Luckily, I remembered having bought a Scotch DVD Maintenance Kit a year or two ago and went looking for it. Unluckily, I had no idea where I had put it and it took me until this morning to locate it.
So it was back to the races as far as I was concerned. Since the DVD did not seem to be encrypted, I decided to simply load each VOB into MPEG Streamclip, locate the audio/video segment I wanted and demux the material. Uh-oh! More problems. Turns out the mixdown channel selections also affect AC3 demux before it gets to A-Pack. Hockey pucks! Back to the drawing board. To make a long story short (I know -- it's already too late), it turns out that MacTheRipper came to the rescue. Simply performed a title only rip in the demux mode and, violá, I had my 6-channel AC3 file and my M2V files readdy to go. QED and repeat the work flow used on the "Sabrina" image dmuxed files.
Basically, I did everything here the same except for the LFE channel. Since the LFE audio check once again appeared to be an empty channel, I decided to spend more time on the matter. Basically, the sound was fine when I played the DVD on the computer -- including the LFE output. After much trial and error I discovered that while DVD Player was outputting the correct audio to all channels of my Logitech Z680 system, the QT player was not. Turns out that if you designate the LFE audio channel to "Center Surround" instead of "LFE Screen," it playes correctly. What's more, after I reconverted the original file with discrete audio channels and with the new designation, the H.264/AAC target file now played the sub-woofer audio but also contained a corrected "LFE" designation reference. (Not going to question things further.)
In any event, have posted the latest "Test" file to the internet in case anyone wants to download it in their normal manner. Here is the URL for opening in either the Safari plug-in or the QT Open URL option:
http://homepage.mac.com/jrwalker4/.Public/SoundTestTrimmed.mov