Compression - how?

[melted_moonlight]

I've bought DVD's from ebay that have 6 full length films on one DVD (including chapters, titles, etc) on standard single layer discs - the quality is very good. I would like to free up some DVD space by attempting to do the same.

Can someone please tell me how I might go about it?

I'm using a MacMini and have Toast, MTR & DVD2one
Thanks

[Baldrick]

Please post in the mac forum section. Moving you.

Using low bitrate and resolution can you store several hours /dvd but the quality wont be good. I would try ffmpegx.

[mats.hogberg]

"quality" is in the eye of the beholder, but I dare say 6 full length movies (=at least 9 hours) on a single layer DVD-R can not by any stretch of the imagination be called quality. It'd require bitrates below VCD specs.
Also, I'd advise against buying this kind of compilations off eBay, since they are almost certainly illegal distributions.

/Mats

[terryj]

more than likely if you have great quality, one of three things
are true:

1. The DVD is actually a DVD-9 (8.5 gb) not a DVD-5 (4.37gb) disc.
2. The movies are all under 77mins long, and even then they
might be trimmed further, losing credits at beginning or end.
3. They have been encoded using a professional bit rate
compressor, such as Apple's Compressor or Sorenson Squeeze,
or BitVice.

If it is the third, provided you "upgrade" to FCP Studio,
then learn the "curve" of Bit Rate Calculation, you too
can achieve similar results. But there is not currently
an all in one solution ( author/burn) that will allow you
to vary the bitrate PER MOVIE to achieve good to great
quality, with enough compression to fit that amount of
content to a DVD-5. Not Toast, Not ffmpegx, and certaily not
iDVD.

[ArtemisG3]

More than likely, the videos are in a reduced resolution of 352x480 (NTSC) or 352x576 (PAL). Reducing the resolution this way, which in turn will reduce the bitrate, is the only way to retain "quality". By doing this, the image will be less "blocky", but may in turn be slightly soft.

[melted_moonlight]

Thanks for your feedback - the films do probably run in around the 85min mark (all George Formby films as it happens).

I shall try some of your suggestions.

[tomlee59]

I agree that "quality is in the eye of the beholder." I have encountered similar DVDs, and they're usually VCD collections authored as DVD. This is very common in China, where you can buy (legally) half a dozen or more TV episodes crammed onto a single DVD. The video uses VCD resolutions, and bitrates that range downward from 1150kb/s. Many of them also use variable bitrate to keep quality from plummeting at the lower bitrates. Audio is sampled at 48kHz, with bitrates that range from 128kb/s (lowest I've seen) to 224kb/s (most common). Well-authored ones look quite acceptable when viewed on an ordinary TV.