What about Problem JVC Full HD Camcorder GZ-HD7E and iMovie HD6 ?

Question

I want purchase Full HD Camcorder JVC GZ-HD7E .
What do you mean about "Problem - Not Problem" by use with
iMovie HD6 ? (PPC G5, 10.4.9 and or iMac G5, 10.4.9)
Thanks .

Answer 1

Most digital video is compressed to save space, generally using lossy video compression codecs. That means that when you go through a compress/uncompress cycle, you don't exactly get the same thing. How bad it is depends on the compression algorithm and the bitrate you choose. If the bitrate is high enough, the compression artifacts might be tolerable. MPEG-2 has a little bit of a bad rap because early MPEG-2 encoders weren't very good, and MPEG-2 can look bad if you choose a bitrate that is too low. Scenese with lots of movement, or low-light scenes with lots of video noise are particulary challenging to compress with good results.
Problems get worse when you have to re-compress, because then you apply a lossy algorithm on top of video material that already has artifacts. It's like making a copy of a copy with a not-so-perfect copy machine. So yes, there is some quality loss when you re-encode the MPEG-2 video for editing. But the loss at that point is minimal, because you are encoding to a very high quality codec. It doesn't make the video any better, but it doesn't make it any worse than it already is. The real quality loss occured earlier, when the video was recorded, and the initial MPEG-2 encoding was performed. Whatever detail was lost there, and whatever artifacts where introduced at that point, cannot be recovered later.
It all comes down to: what do you consider acceptable? Compare it to music. Yes, a CD is of much higher quality than a MP3 song. But most people can't tell the difference, and are just fine with MP3.
With HD, you don't really have a choice. The Canon HV20 - like all MiniDV based HD camcorders - uses MPEG-2 compression, too. It only shares the tape media and Firewire connection with SD MiniDV camcorders, not the DV compression algorithm. Importing from the HV20 into iMovie goes through the same re-encoding process. The AVCHD camcorders use MPEG-4 compression.