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WizOSX · Apr 26, 2009, 03:03 AM

I just burned a dual layer DVD on my MacBook (10.5.6) and tried to use it on my daughter's G4 Mini (10.4.11). No go, it only sees one side. I also tried plugging in an external USB dual layer drive, and again, no go. The external drive and disc read fine on my machine. Any thoughts?

tooki · Apr 26, 2009, 05:40 PM

Burned dual-layer DVDs simply do not have the broad compatibility of other types of discs, though that doesn't explain why it doesn't work with the external drive...

Simon · Apr 27, 2009, 03:10 AM

PPC Mac minis never had DL drives. Those only arrived with the Intel mini so that DVD will never play on your daughter's mini.

If the external drive managed to play back the disk on your MB it should also do so on the Mac mini. Try it again.

I use an external DL burner together with all kinds of Macs including a PPC mini. Never had any problems with that combo.

P · Apr 27, 2009, 03:29 AM

Originally Posted by Simon

PPC Mac minis never had DL drives. Those only arrived with the Intel mini so that DVD will never play on your daughter's mini.

Clarification: duallayer DVD-ROMs will work - they work on Macs from the freaking nineties. It is DVD+R DL, ie burnable duallayers, that are a bit of hit and miss.

The external drive thing is stranger, though. USB, I assume? What are you trying to do with the DVD - boot from it, or just read the data?

WizOSX · Apr 27, 2009, 04:28 AM

I was wrong. The machine does see the whole disc. The problem is that DVD player will not play the disc.

Backing up:
I used Ripit to rip a DVD and then used finder to burn it on a DL disc (the movie was 132 minutes, 7.5 gb). The movie plays fine on my MacBook and also plays fine on my Sony DVD player. It will not, however, play in Tiger's DVD Player in the Mini. Did Apple make some major changes to the DVD player in 10.5 so that discs made that way would play?

Simon · Apr 27, 2009, 04:55 AM

Forget about DVD Player.

Instead try out VLC. It's free.

tooki · May 3, 2009, 06:55 AM

Originally Posted by Simon

PPC Mac minis never had DL drives. Those only arrived with the Intel mini so that DVD will never play on your daughter's mini.

Clarification to the bazillion people who don't get this: only burning dual-layer discs is new. Reading dual-layer discs has been a part of the core DVD specification since the beginning (1996 or 97).

The problem is that burned dual-layer discs simply aren't close enough to a pressed disc to have wide read compatibility.

Spheric Harlot · May 3, 2009, 07:27 AM

Originally Posted by Simon

PPC Mac minis never had DL drives. Those only arrived with the Intel mini so that DVD will never play on your daughter's mini.

Every DVD player ever built can play double-layer disks. That's because pretty much every single commercial movie DVD ever pressed is a double-layer disk.

The problem is, as tooki described, that DL burnable disks still vary too greatly from spec to be playable in all drives.

Simon · May 3, 2009, 08:14 AM

P already spelled it out for you guys a week ago.

It's fairly obvious that reading pressed DL disks should work on ever Mac (with a DVD drive) since OS X itself comes as a DL DVD, just like most movie DVDs you buy. But burned DL disks are usually trouble. And with the PPC Mac mini I know for a fact that it doesn't work because I've run into exactly this issue with my own mini on two separate occasions.

Spheric Harlot · May 3, 2009, 08:43 AM

Originally Posted by Simon

And with the PPC Mac mini I know for a fact that it doesn't work because I've run into exactly this issue with my own mini on two separate occasions.

My 1.25 GHz G4 Mac mini has the stock Combo drive and reads Double-Layer DVD+R JUST FINE. I have a burned double-layer disk in the drive as we speak.

In fact, I installed Leopard onto it from a burned backup copy.

FWIW, I've used imation and, more recently, Verbatim DVD+R DL disks, and never had a problem.

Simon · May 3, 2009, 09:33 AM

I have yet to see a DL DVD+/-RW that will work in my PPC mini. In fact the built in DVD drive is such a piece of junk I simply stopped using it altogether. Instead I've hooked up a cheap Samsung 22x DL USB burner which works like a charm at half the price of one of these crappy 8x slot-loaders.

Spheric Harlot · May 3, 2009, 11:13 AM

Well, I probably just have the legendary Magic Mini™...

Simon · May 3, 2009, 02:43 PM

Obviously. Pretty much everybody else's slot-loader sucks.

Spheric Harlot · May 3, 2009, 03:43 PM

Maybe you should buy better media.

We've seen it with every optical medium over the past twelve or so years: When a new format hits, the burnable media are all over the place, and finding a brand that works with both your burner and your readers is hit-and-miss and walking out of a store with single units of ten different brands.

Back when I got my first single-layer DVD burner in 2003, the ONLY brand that would both burn and read reliably for me was Apple's own.

What double layer media are you using?

Simon · May 4, 2009, 02:25 AM

There's nothing new about burnable DL DVDs. You can buy the most expensive media and it still won't help if the drive's bad. Slot-loaders just suck.

Slot -loaders are much more compact than tray-loaders, but they are also slower and far less reliable. The fact that so many Macs have bad optical drives has primarily to do with Apple only using tray-loaders on the MP.

P · May 4, 2009, 06:10 AM

The reason many DVD+R(W) DL discs don't work on older players is the so called "book type" which hints to the drive how the disc should be read. DVD-R DL has the same book type as regular DVD-R discs - that is not the case for the + drives.

A drive manufactured before the DVD+R DL standard was set will obviously not recognize the book type. If it works or not depends on how the drive's firmware will handle an unknown book type. Many of Apple's players seem to fail silently - other players may try to make it work. Apple has not shipped many firmware updates for its DVD drives recently (possibly because they tend to get subverted to make regionfree RPC1 drives) but in some cases it's possible to update a drive in Windows and have it work on the Mac. It should be possible to subvert one of Apple's updaters to use a different firmware image, but I've never tried - the (slotloading) drive in my iMac G5 works very well, except for only burning at 2.4X with most discs.

Using high-quality discs does actually help a bit. The differences between the various + and - versions are related to error correction. If there are no errors to correct, obviously even an incorrect guess from the drive firmware will result in a workable disc.

Spheric Harlot · May 4, 2009, 08:08 AM

Thanks for the detailed background!