4 Hour DVDs?

[willrob]

I noticed that Memorex DVD+R disks are labled as "4 Hours Video". Most DVDs claim two hours of video, and of course if you use iDVD, the most you can get is 90 minutes of lower quality images. So how does one get 4 hours of video on a DVD and what quality can one expect?

I can't use +R disks yet, but maybe after Panther is released I might consider a Pioneer 106 mechanism—although it's unclear if even Panther will enable the +R/+RW mode of these drives.

Williamr

[andkiich]

Amount of video on the disk is based on what bitrate you use. When encoding your video, setting the bitrate lower will result in a smaller file size, which means you can fit more onto a disc. Quality is always subjective, so my suggestion to you is to invest in some RW discs and experiment. I find that, for me, I can live with 3 - 3.5 hours on a DVDR quality wise. After that, the macro blocking and artifacting are a little too much for me to consider acceptable.

If you want to go with a lower bitrate to fit 4+ hours on a single DVDR, you might want to also consider doing a half D1 resolution DVD(352x480). The results will look better than at full DVD resolution at the same bitrate.

Remeber also, that MPEG2 compression is a function of length of the video and bitrate. The size of the clip will not change because the resolution changes.

[ZeroSix]

a lot of times discs are rated with times like that because the presense of set top DVD recorders are becoming more and more mainstream. They have EP, LP, and SLP modes just like VCR's did. you can get anywhere from 90 minutes to 8 hours on one DVD-R depending on the bitrate.

[willrob]

I think I understand your point. But wouldn't these techniques apply to any DVD-R disk? What's so special about these Memorex DVD+R that makes Memorex hype them as holding 4 hours? Memorex DVD-R are only rated as 2 hours of video.

Williamr

[pants]

they would apply to all dvd writeable - rewriteable discs.

[ZeroSix]

My guess is because Memorex is part of the DVD+RW alliance, and they would most likely be trying to convince customers that the +RW format is superior to the -RW format. I could be all wrong about this.

However, on a technical note, 4.7 GB is 4.7 GB no matter what. As pants stated, it doesnt matter what media type you use.[/url]

[galactica]

Unless you want to easily view these on your mac.
Then you will find +r/rw disks can be a PAIN.
well, for the typical mac user. it can be done.....

[MarcoEsc]

But wouldn't these techniques apply to any DVD-R disk? What's so special about these Memorex DVD+R that makes Memorex hype them as holding 4 hours?

You are correct. The "four hours" is just marketing speak.

[tnelson]

I personally try to keep the encoding rate above 4 mb/s. To give you an idea of what would be needed to put 4 hours of video and audio on a single 4.7 GB DVD-R disk, consider the following:

To put 4 hours of video and audio, using aiff encoding for the audio, you would need to encode at a bit rate of .83.
If instead you took the audio and used AC-3 compression to reduce the audio portion, you could encode at 2.33. These bit-rates do not include any overhead for markers, titles, etc.

Given the low bit rates needed, youwill probably be better served by breaking up the production into two or more disks.

Tom N.

[major]

It should be worth trying encoding at KDVD format. It allows about 5 hours of video at near SVCD quality on a 4GB DVD.