newbie capturing format question (Mpeg or AVI)

[bsmilde]

I tried searching for some answers on the boards on my little problem but wasn't quite sure how to formulate it in the search box so I got hundreds of results that weren't quite what I needed, so I decided to create a new post.
If this question has already been answered (or answered more then once) my apologies.
I assume it is rather simplistic but for some odd reason I couldn't quite make sense of it.
When I capture (transfer?) video from my DV camera in Pinnacle 8 I had the choice to either capture it as high quality Mpeg or high quality AVI.
The AVI seems to be bigger in size (as in diskspace).
What is the basic difference between these two formats, and which one would be preferrable? Less diskspace needed is ofcourse nice, but good quality is just as important I think.
If anyone would be able and willing to shed some lights on these basic principles it'd be greatly appreciated.
Thanks in advance for your patience.

[bugster]

DV is not captured, at least not in the usual meaning of the term as in converting analog video signals to a digital form and storing them on a PC. DV is already digital so you are basicxally copying it to your PC, which will either encode to mpeg as the data is received (your mpeg capture option) or simply store the received data on the HD in an avi wrapper.

The Avi should be an exact bit for bit digital copy of what is on the tape, so you wont get the quality any higher. The Mpeg starts with the same data but it is compressed in real-time as it is received and then stored in mpeg format.

If you want to edit, or want best quality, then capture in avi format, do your editing in avi format and use a software encoder to convert to mpeg later.

If all you want is a quick method of producing (S)VCD or DVD and are happy with the quality of the mpeg 'capture', and you don't need to edit, stick with it.

[bsmilde]

Thanks for the quick reply bugster.
I understand that it's not quite capturing indeed, for the reason you mention, so I'll try to remember to call it video transfer from my DV camera to my computer.
Just to make sure I understand it, basically storing it as an AVI gives a higher quality, it is easier to edit but it takes more diskspace, an Mpeg on the other side compresses it automatically, saving diskspace but at the cost of quality and ease of editing?
My apologies if I am stating the obvious, if that would be the case.

[i_am_dave]

Good questions.

Here are the differences in a nutshell:

AVI is uncompressed video, therefore it is of the highest possible quality. Unfortunatly, it also takes about 12 Gigs to capture an hour of video.

MPEG2 is compressed using a number of techniques including calculating differences between each fram and a discrete cosine function. Similar to how the images from a CAT scan are processed. There are many parameters that can be tweaked that affect the final file size and the quality. As a rule, the smaller the file, the worse the quality.
A good encoder with the properly chosen parameters can encode an hours worth of video into about 2 Gigs. with little noticeable loss in quality.

I use Ulead myself, but never let it do the encoding for me. Instead, I do all my work with AVI files, until I get the production finished.
I then convert the AVI to MPEG using TMPGEnc since it lets me have full control over all encoding parameters.

Hope this helps!

[FOO]

AVI is not uncompressed video. It's not exactly clear what AVI
is. It can be uncompressed or compressed with any of millions
of codecs.

DV is not uncompressed video. Uncompressed video is over
100 gig/hour. DV is 13 G/hour

[DrWafer]

absolutely right.

1 min of uncompressed video is 1,5 gigabytes

1 min avi compressed with huffyuv or PICvideo MJPEG quality20 codec is 650 mbytes

1 min avi PICVideo quality19 is 250 mbytes.

1 min avi DviX 5 (default settings) is 6 mbytes(if the audio is layer3)

[i_am_dave]

Yep, your right.
I automatically think of DV as AVI since that is what I work in most of the time.
All AVI is, is a container. It get really confusing since I have a friend that uses the term AVI to describe his Divx files.