Quicktime Export Fails to Recognize Audio in MPG1 files

Question

When exporting MPEG1 to any other format with QT Pro, audio options are greyed out ('No Audio in Original'), and, predictably, the export file has no audio.
VisualHub exports MPEG1 with audio just fine. But I've paid for QT Pro, and not VisualHub.
This has to be a bug in QT, right? MPEG1 is, unfortunately, still pretty common, and I would think Apple wants users to be able to put whatever video they have on their iPods.
Thanks in advance.
QT 7.1.3
OS 10.4.7
NB: Is it possible for moderators to retroactively edit topic subjects to be much more specific? The more likely a visitor is to find her topic answered, the fewer new topics there are, less repetition, etc.
Even better, consolidating the most common questions into 5 or 10 stickies would save visitors much time, and the people who answer these questions, exponentially more time.

Answer 1

Thank you for the answer. The information was useful, the tone was not what I expected. When I asked whether more specific headings could be encouraged, I meant it out of sympathy for the moderators/answerers, not to incur their ire. Perhaps it would have been better if I'd left out the editorial comment.
I searched for 'audio', which I thought was a more technical term than 'sound'.
I read the indicated specs for QT above. The MPEG shortcoming is not laid out there clearly in any sense. MPG is not listed as an export format, so from that I would conclude QT can't export to MPEG1.
It is clear in the Apple article. For it to be 'clear' to anyone right away, it should be added in one sentence to the relevant help section of QT: 'QT will not export files with some codecs because of their proprietary neature.'
Or it should be in a pop-up message as soon as you try to export an mpg: 'Because mpeg is ownded by someone else, export will only render video'.
I believe I asked a valid question, and provided a specific account of my problem, so this post will be useful for future browsers.
Because VisualHub dealt easily with mpg, I thought QT must too. I was wrong.