Digitized Camcorder Tapes, Edited by iMovie, Recording to DVD

Question

I recently had a commercial firm digitize some 20-year old 8mm camcorder tapes that I would like to edit and put onto DVD's.  They advised me that editable digital copy would not fit on DVD's and so I provided a portable hard drive.  The tapes that had a full 2 hours of video came out with about 28GB of digital content.  I hope to use iMovie for editing purposes on my iMac, a new experience for me.  What puzzles me is that my DVD+R blank disks claim to be able to hold 4.7GB of data or 120 minutes of video.  Assuming that editing may discard perhaps only 25% of the 120 minites of video, I have a hard time understanding how editing 28GB of video is going to fit on a DVD that claims to hold only 4.7GB of data in spite of the fact that it also claims to hold up to 120 minutes of video!  I would be most grateful if someone could explain this apparent discrepancy between DVD data capacity and video capacity.  Will I have to chop up a 2 hour video into smaller bits or is there something about editing that will render the end result in a form that will fit on a DVD?

Answer 1

Worry not.
Digital video can take up to 13GB per hour, which is why you need lots of space for iMovie.
iDVD compresses this to the standard DVD delivery format of mpeg2 which, as they have correctly informed you, is not editable.
iDVD is not concerned at all with the size of the files it receives from iMovie, only the length. A single-layer DVD can hold 120 minutes of video but this includes titles, transitions etc. A double-layer DVD doubles that.
iDVD offers a choice of encoding settings:
iDVD encoding settings:
http://docs.info.apple.com/article.html?path=iDVD/7.0/en/11417.html
Short version:
Best Performance is for videos of up to 60 minutes
Best Quality is for videos of up to 120 minutes
Professional Quality is also for up to 120 minutes but even higher quality (and takes much longer)
Professional Quality: The Professional Quality option uses advanced technology to encode your video, resulting in the best quality of video possible on your burned DVD. You can select this option regardless of your project’s duration (up to 2 hours of video for a single-layer disc and 4 hours for a double-layer disc). Because Professional Quality encoding is time-consuming (requiring about twice as much time to encode a project as the High Quality option, for example) choose it only if you are not concerned abo
In both cases the maximum length includes titles, transitions and effects etc. Allow about 15 minutes for these.
You can use the amount of video in your project as a rough determination of which method to choose. If your project has an hour or less of video (for a single-layer disc), choose Best Performance. If it has between 1 and 2 hours of video (for a single-layer disc), choose High Quality. If you want the best possible encoding quality for projects that are up to 2 hours (for a single-layer disc), choose Professional Quality. This option takes about twice as long as the High Quality option, so select it only if time is not an issue for you.
Use the Capacity meter in the Project Info window (choose Project > Project Info) to determine how many minutes of video your project contains.
NOTE: With the Best Performance setting, you can turn background encoding off by choosing Advanced > “Encode in Background.” The checkmark is removed to show it’s no longer selected. Turning off background encoding can help performance if your system seems sluggish.
And whilst checking these settings in iDVD Preferences, make sure that the settings for NTSC/PAL and DV/DV Widescreen are also what you want.
http://support.apple.com/kb/HT1502?viewlocale=en_US