I have a ~70mb (3 minutes long) m4v video that I need to get to a much more reasonable file size for playing on a site that will primarily be accessed via iPad.
File size is directly proportional to the combined total data rate of your file. If you want a smaller file, then you need to reduce the audio + video data rate of the file. Unfortunately, overly reducing the data rate can adversely affect the audio/video quality of the file. Depending on the encode settings (data rate, encode matrix dimensions, display dimensions, entropy option, intra/inter frame options, number of encode passes, etc.), user tolerance for minimum quality level, the specific target ISP speeds required, application to be used, etc., the possibilities are relatively endless. Basically, the file you describe above has a combined total data rate on the order of 3.1 Mbps. Such a data rate might be considered low for a full 1080p file, adequate for a 720p file, or excessive for a VGA file depending on the graphic complexity of the file. In short, it is difficult to properly answer your question without additional information or actually seeing the file in question. (I.e., proper encoding of content is as much an art as a science.)
I don't know if it matters, but the video will need to play automatically upon page load.
It may matter depending on how the web site is coded and/or how the content is to be accessed by the target iPad device.
From the Export pop-up menu, there should seemingly be an option to choose "Movie to QuickTime Movie." I have only 480p and iPod/iPhone/iPad options(which I believe would result in a viewing frame that is too small).
The option and tutorial you reference require the use of QT 7 Pro which the option you reference sounds nore like a QT X player export option. (Once, again, what you can do will depend on the software you are trying to use to create your file and a 480p file could normally be anything from an 853x480 (16:9 aspect) file to a 640x480 (4:3 aspect) file or an anamorphic 720x480 file displaying in either the 16:9 or 4:3 aspect. So I really don't know what you consider a "small" viewing frame.
How can I proceed with web-optimizing this file in Quicktime? (Or is there a better solution? I tried Sorenson Squeeze, but that had a large watermark..)
As previously mentioned, there are many applications that can be used here—QT 7 Pro, MPEG Streamclip, QT X, HandBrake, etc. to name just a few. I personally would recommend the free HandBrake app since it offers both manual and automatic preset options, as well as, allowing you to create anamorphic or non-anamorphic encodes targeting either a fixed level of quality or a target file size depening on your needs. Unfortunately, the more options you have, the more decisions you need to make which means the more you need to critically analyze your target needs/requirements—which is frequently something many video users are trying to avoid.
Basically, if you want more specific advice, you will first have to better define your specific needs here.
