[MacDV] Storage

[Derek Roff]

I think we've got some terminology problems in this discussion.  By the 
description of your process, it sounds like you are converting your VHS 
tapes to DV25 video (often called simply "DV"), and editing it in 
iMovie.  This is what I do.  This kind of digital video takes up a bit 
more than 13 GB per hour, and iMovie lists its resolution at 640x480. 
(Other video programs may call the same video 720x480).  You can't make 
that hour of video any smaller in file size, without changing its 
format or resolution in some way.  Usually, that means applying some 
kind of additional compression.

iDVD does, that, converting the DV video into MPEG2.  You have some 
compression choices, and iDVD will make some choices for you, depending 
on the amount of video you are trying to put on a disc.  But at the 
iDVD default for one hour of video, the file size will probably be near 
4 GB.  The resolution will still be the same as what iMovie calls 
640x480.  It will just be compressed in a different way.  You can also 
export from iMovie to QuickTime, and choose to modify the format, 
compression, and resolution, if you desire.  You can get pretty good 
looking MPEG4 video at the same iMovie 640x480 resolution, and compress 
to somewhere around 750 MB per hour.  That's what I do, before 
uploading to YouTube.  YouTube then compresses and converts the format 
yet again, and changes the resolution.

Based on the file sizes quoted below, we can draw some conclusions 
about Don Tully's video project.  The iMovie project has more than an 
hour of video in it, although much may be unused and duplicate clips, 
or things in the trash.  His 3 GB iDVD project is probably a bit under 
an hour.  And most importantly, we can conclude that the QuickTime 
movies in the Garage Band and iDVD folders do not contain the video. 
There is no way that a 4.4 MB or 2.6 MB file can contain any useful 
amount of video. It does no good to archive these files by themselves. 
If you copied these files to another computer, they could not play. 
These files contain pointers to the actual video files.  They can play 
the video on any given computer, only if they can find their 
corresponding video files.

Jumping back to the original question of what to save on the hard 
drive, the answer depends on future goals and needs.  Will you need to 
access all of the raw footage later for possible re-editing.  If so, 
you will need a lot of storage.  If your ready to dump the raw 
material, but think you might do a bit more polishing of the project, 
then keeping the iMovie project might make sense, after getting rid of 
the trash and unused shots.  That would bring an hour-long project down 
to about 13 GB.

If you're planning a bunch of future projects, then a group of iMovie 
projects may take up too much disk space.  If you don't think you will 
do a lot of editing later, maybe saving the iDVD project file or the 
DVD image file would make the most sense.  The two will be similar in 
file size.  The latter can be created in iDVD, using the File>Save as 
Disc Image command.  With the disc image, you can burn as many new 
copies of the DVD as you like, using Disk Utility.  With the iDVD 
project file, you can adjust menus and chapters, add or subtract video 
clips, as well as burn additional DVDs, making it the more flexible 
choice.  In either case, if you really want to edit again, you can 
extract the video and turn it back into DV video with MPEG Streamclip. 
There will be some quality loss, but it is an option.

Derek


--On Tuesday, February 16, 2010 12:00 PM -0800 
macdv-request at listserver.themacintoshguy.com wrote:

> Hi Listers - I have a rather elementary question about the most
> efficient way to store iMovie and iDvd projects.  I am converting old
>  VHS tapes to DVD. I edit them using iMovie and then send them to
> iDvd   to burn.  When I'm done I have a 27GB iMovie project, and 3 GB
> iDvd   project, a 4.4 MB Quiktime movie in my Garageband folder and a
> 2.6 MB   QT movie in my iDvd folder.  I'd like to keep something on
> my hard   drive for future reference.  What's the best way to do
> this, please?



Derek Roff
Language Learning Center
Ortega Hall 129, MSC03-2100
University of New Mexico
Albuquerque, NM 87131-0001
505/277-7368, fax 505/277-3885
Internet: derek at unm.edu