How to export/convert FCE movies into AVCHD format?

Question

I have read a number of topics addressing similar questions but haven't yet found a satisfactory explanation of why it is not simple to do the opposite of what the Log and Transfer function does when importing AVCHD footage in FCE.
The footage shot by camcorders is heavily compressed (my Sony camcorder generates 24 Mbps -that's BIT, not BYTE, per second- at its highest rate), thanks to their on-board processor (BIONZ in the case of my camera: http://www.sony.com.sg/microsite/dslr/technologies/bionz.html). Yet, when played by hardware (such as the camcorder itself) on a HD-TV, the movies look gorgeous. Hence, this is a perfectly acceptable compression. And it does not take an enormous amount of memory. For instance, a ~10 min sequence encoded at 17Mbps on my camcorder occupies ~2GB.
However, once imported by FCE, each frame is individually extracted for ease of editing, and the size explodes. So exporting the resulting edited movie (in 1080HD) as a QuickTime movie is a recipe for rapid hard drive saturation (and YouTube export failure). I have tried several codecs offered by FCE (H.264, mp4) but the resulting compressed videos are still humongous (North of 5 GB for the example I mentioned).
It would seem that what the BIONZ processor achieves in real-time should be within reach of a modern CPU at a much slower pace (we are used to several hours of rendering, aren't we?). Yet, that is not the case. Is there a good reason for that?
Thanks for your comments.

Answer 1

Tom,
I first noticed it when looking at the videos created by FCE (that was the origin of my post) played in QT. Usually I play them at the default size chosen by QT for my screen, which is something like 1400 x whatever.
The problem (in QT) occurs at any viewing size. It is of course less apparent at smaller size, but it's there.
Then having figured out that I would not improve the output, I looked at the sequence in FCE. Looking at the video played in the Canvas, the jagged edges are there. Of course to see them well, it is best to zoom a bit, but they are there at any size.
Having figured this out, I tried to reimport the original footage using Log and Transfer. The window that opens has a preview, and I saw the jagged edges there too (whatever size the preview panel was set to). I could not find any settings that I could play with to avoid this problem.
My naive conclusion is that FCE does not know how to handle 60i footage as "well" as my TV does. I am ready to believe that in reality FCE does a more accurate job of rendering the two fields into a single frame, but as a viewer, I prefer the rendering of my TV. And since both engines have been designed by humans, I would tend to say that the engineers of my Samsung TV had a better grasp of what is a good rendering of a 60i footage than did the engineers at Apple (or elsewhere) who wrote FCE.
Now, I may be missing some basic thing here, and I am ready to learn.
BTW, the jagged edged effect I am seeing is what is shown on the first picture of the wikipedia page you pointed me to.