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Creating DVD Menu Systems
By Video Consultant | July 3, 2007
DVD authoring refers to the process of creating the menu and navigation system for a DVD. It also includes adding chapter points and other fun things like background music.
In the editing section I mentioned that I save my edited movies in the AVI format and then bring them into Ulead DVDMovieFactory to author the DVD’s.
I also mentioned that the any video length over an hour would have to compromise quality to fit onto a DVD. You can stretch this to close to two hours thanks to the AC3 encoder in DVDMovieFactory and the excellent MainConcept Encoder that DVDMovieFactory uses behind the scenes.
MPEG movies consists of two parts. The video and the sound. Most cheaper encoders only allow you to encode with something called Linear Pulse Code Modulation (LPCM). This format can take up almost 1/4 of the space of a movie. If we could use less space for the soundtrack we then have more space available for the audio. That’s where AC-3 audio encoding comes in.
Dolby Digital is the trademarked marketing name for Dolby Laboratories’ “lossy” AC-3 format. You can think of AC-3 as a cousin of MP3. The same sound quality as LPCM but with a lot less space.
Ulead DVDMovieFactory has the option to encode audio as AC-3. Something no other program has in it’s price class. For the most part you should always choose AC-3.
BitRates And Video Size
In very simplistic terms the bitrate controls how much information is sent to the screen or display. A lower bitrate may produce visible artifacts. The picture will have more of a “mosaic” look to it. Usually fast action sequences require a higher bitrate.
The total bitrate for a DVD can be about 10Mbs (Megabits/second). There are reports that anything over 9MBS may cause problems with certain DVD players.
Choosing a bitrate is all about compromise. If you encode at higher bitrates you may exceed the space on the DVD. Too low and the quality will suffer.
A way to determine the maximum bitrate to encode at is to use a bitrate calculator like this one:
VideoHelp.com BitRate Calculator
or you can try my own bitrate calculator.
You simply enter the length of your movie and the calculator will tell you what to set your bitrate to.
How Low Can You Go ?
You can go as low as what looks good to you. Personally I don’t like to go below 5.6Mbs (5600 Kbs or about 1 3/4 hours).
There are some graphs at DigitalFaq.com that show rather nicely the correlation between quality and bitrate. Keep in mind you will be looking at the 720X480 chart.
In summary a range 5.6-8 Mbs is what you will be working in most of the time.
Burning Your Masterpiece
As mentioned before some authoring software titles will allow you to burn to a DVD. Some people like to burn with other programs like Nero. More about burning here.
It is worthwhile to discuss test burns. Nothing is worse than wasting a few hours encoding and finding out your DVD looks like crap on the TV.
I like to create small clips (1-5 minutes) of the movie and burn them at the calculated bitrate onto a DVD-RW. I then play on the TV to see if the quality is what I expect. If it’s not looking too good I may try to increase the bitrate or reduce the length of time from the movie to reach a certain bitrate.
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Topics: Home Video |
August 15th, 2007 at 6:57 pm
I thought you would have explained about Menu but you are talking about AC-3 encoder and bitrate in detail than Menu. It is about Menu isn’t it?
Thanks