There are a few principles to get around first.
The video recorded to the minidv tape is dv, it is compressed at a ratio of
around 5.1.
If you capture as dv-avi - which is the dv signal wrapped in an avi wrapper,
then it will be identical to the video on the tape.
Every single frame in the dv-avi is an actual recording of what the cam saw,
so for PAL, you have 25 real frames every second.
As each of these frames is real, you can make an edit cut after frame 1 or
frame 76895, or any inbetween,
If you save as dv-avi to your hard drive the video will still retain the
exact same quality.
If you add transitions to the edit cut points, then quality will be very,
very, very, very slightly lowered, but not at all noticeable even on
profesional quality monitors.
Mpeg is compressed to around 20.1. So you start with a much more compressed
video.
You can see this, by 1 hour of dv-avi consume 13gb of hdd. 1 hour of best
quality Mpeg consumes about 4gb.
Mpegs are made up of GOP's, group of frames. These frames are i, b, and p.
An i frame is an exact recording of the camcorder, the frames between these
i frames are made up, using the info on the i frame before it and the i
frame after.
GOP's can be from a few frames apart to many frames apart. This is one way
of making the video fit more on a disc, so the less that fits on a disc, the
smaller the GOP. A samll GOP may still be an i frame every 15 frames, so in
fact you get less than two real frames every second (PAL).
When you edit, you can only make cuts at i frames. So if the action changes
mid GOP, you have to either cut to it before hand or cut to it after it has
started.
When you save this edited Mpeg, unless you have a programme which will allow
you to save compatible files, you will then end up recompressing a
compressed file.
If you have ever saved a jpeg still a few times you will notice each time
you save it it gets smaller in size, and gets lower quality. If you used a
still tiff/bitmap file and made changes and saved it, it will not decrease
in size and retains it's quality. This is the same for Mpeg and AVI.
There is also this for mpeg editing.
Mpeg2 files use programme time stamps to keep the audio and video in sync.
Therefore when making your edits to the mpeg file when you preview in your
editing programme or in the computer dvd player, before burning, the audio
and video always appear to be in sync.
The problem comes along when the Mpeg2 files are authored to the dvd and
burning commences. In the authoring, the VOB files which are created,
discard the programme time stamp information and this can lead to very small
audio and video sync problems. The more edit points there are, the greater
the problem will become. Straight cuts are generally not as bad as using
transitions at edit points.
On to Premiere elements.
I've not used it, but I use Premeire 6.5. It is a crakcing programme, and by
the reports I've read elements 2 is superb value for money.
It is right in that you can import mpeg files without loss of quality. All
you are doing is using the file from the dvd, or I found it best to copy the
Mpeg to the hdd first, much faster seeking times. The loss of quality is in
the recording of mpegs, when compared to avi.
The main problem will come in your authoring app, when you come to make the
vob files.
I still believe if you want to edit, then use a minidv.
If your editing is minimal, then you could get away with a dvd cam.
If you don't want to do any editing and want to just play a dvd, then they
are great camcorders, as the dvd made is pretty darn good quality.
I hope I've been clear in this, let me know if you don't understand
anything.
--
Graham Hughes
MVP Digital Media
www.myvideoproblems.co.uk
www.dvds2treasure.com
www.simplydv.com