Info about DVD formats

Lately I've been asked more often if I can record something onto a DVD, rather than tape, and my answer was “not at this time, because of compatibility problems.”  Now, I can produce them, but the problem of whether you can play them is yours, dictated by what your player can handle.  There's a number of issues regarding the format that they're recorded in, the discs that they're recorded on (the type and quality), the compatibility of the player (how well it adheres to the specifications and tolerates deviations), and likewise for the recorder.  Some discs simply will not be playable in some DVD players, and that was the main reason why I hadn't got into producing DVDs, earlier.

Until such time as all home DVD players become more versatile, and the manufacturers decide what is going to be the standard way to record DVDs, we're in the same boat as the old VHS versus Beta debacle (having the opposite machine of what you need, in a given situation).  I don't want to have several different recorders for each standard, and even then it mightn't help (some players cannot play back burnt discs, no matter what format was used).  Having a multi-format capable recorder wouldn't help, either, for the same reason (much of the problem is at the playing side of things, not the recording—writable discs were developed after the read-only discs, you need a new player to handle the newer disc formats, and it needs to be designed to play the writable discs).

For what it's worth, it's typical that the really cheap players can play just about anything, and the more expensive decks will only play movies pressed by the major film distributors.  Although that's beginning to change, now, with the big brand name decks playing other discs, too.  But the cheaper decks do still usually support more recording formats.

My old recorder was a stand-alone Liteon “All write” LVW-5000 DVD±RW recorder, and even though it's a plus/minus machine, it makes all its recordings like plus ones.  I know its recordings didn't play back on a friend's Magnavox recorder, won't play back on my LG DV4721P DVD player, nor our LG DC593W combination VHS VCR and DVD player (which has essentially the same DVD deck).  Its recordings do seem to play fine on my AWA DP220 DVD player, so long as you use decent quality discs.  And although it will play back on my XMS-150 DVD player, it fouls up if you try and rewind or fast-forward through the disc.  This seems a common problem with DVD+ recordings—the plus format is non-standard, and therefore not very compatible, and not consistently implemented (there's no real standard to comply with, nor design for).

My next recorder was a stand-alone Philips DVDR 3460 recorder, and while it's not the nicest deck to play discs on, it did much more compatible recordings than the Liteon does.  So far, its recordings have played back on every other deck that I've tried them on, although some playback decks that weren't designed for playing plus or minus DVDs sometimes have problems rewinding or fast-forwarding while you watch the picture (fast picture searching).

My current recorder is a Sony RDR-HXD509 combined hard drive and DVD recorder.  It's the only machine that I've seen to properly produce DVDs, with a new VOB file started for each new title, and its recordings have played back properly on every player that I've tried.

Some people have heard of some of these issues (see below), as they've been around since DVDs started to become popular (the first few issues discussed—zones and copy protection), but a few of them are newer issues which have come about since the prospect of making your own discs became viable (the latter issues—data and disc formats, and disc capacity).


Most discs released by the movie houses are intended for certain zones of the world, in a futile attempt to control their distribution.  The idea is that the discs can't be viewed in players for certain zones, although many players can be set to ignore the zoning information.  It's also in ignorance of the fact that if the distributor doesn't make their product available very quickly, pirates will have released their own discs ahead of them, and taken away their potential customers.  It also means that if you bought discs in one zone, then moved to another part of the world, you couldn't legally (and possibly technically) be able to play them.  Zoning is just a dumb idea.

I'm not aware of zoning being a problem with self-made discs, but I suppose there's a possiblity of some daft manufacturer making a DVD recorder write the disc for a specific zone, and that might make it difficult for you to play the disc if you moved zones).

(By self- or individually- made discs I'm referring to individually burnt discs, whether you or I made them, on a computer-based or a stand-alone DVD recorder.  As opposed to mass-produced pressed discs; the type that you rent or buy from movie houses.)

Macrovision copy protection

This is another futile attempt to stop people copying discs onto other mediums via the video out connectors.  It may make it difficult for the casual pirate, but the veteran pirate will not be hindered the slightest by this, and the innocent user can get inconvenienced by it:  Some players will always play back DVDs with the Macrovision copy protection signal on top of the video signal, even if the disc hasn't been authored to use it (such as your own self-made DVDs).  This can make it difficult to play or copy your own discs, even when you should be able to, unrestricted.

Macrovision works by mangling the video signal beyond the proper video specifications.  Apart from making it difficult to record (until you remove the Macrovision signal, which isn't very hard to do), it can also make it difficult to just watch (if you have equipment susceptible to it, and you don't have a way of removing it).  On DVD players, Macrovision is added after the fact (the disc indicates it should be played with Macrovision, and the player applies the signal to what it reads off the disc—the video signal isn't encoded on the disc with Macrovision as a part of it), but Macrovision protected video tapes are recorded with the Macrovision already embedded into the video signal.

CSS (Content Scrambling System) encryption

Another futile attempt to prevent copying.  Again it hinders the casual pirate (the ones that don't make a dent in sales), though doesn't actually stop them copying it (it's very easily circumvented), and does absolutely nothing to stop the veteran pirates (the ones that do harm sales).  Basically put; if you can play it, you can copy it, end of story.  The converse is also true; if you make it very hard to copy, you'll also make it impossible for some people to play it.

I'm not aware of CSS being a problem with self-made discs.

Copyrighted, or not duplicatable discs

Although I've not seen it, I've heard of problems where self-made discs have been written in a “copy protected” manner which prevents duplicates being made of them.  My own CD burning software (Nero) insists that all my own discs I've made are copyrighted, although I've not opted to burn them that way (there's no option to select or deselect such a thing).  Heck knows what you're going to do if you need to copy a disc, and it's the only copy available to you, but the machine won't let you copy it.

Digital Versatile Disc

DVD literally means “digital versatile disc”.  It's a disc that can be used in a multitude of ways (for different tasks), the most common one is DVD-Video (movie discs), next would be data discs on computers DVD-ROM or DVD-RAM, and least common would be DVD-Audio.  The information is stored on the disc on a layer (or across several layers) within the disc substrate.  There's names for the different types of discs according to how many layers they have (e.g. DVD-9).  And the method burners write to discs differs, too, dictated by the type of disc itself (“write-once”, “rewritable”, or RAM discs, and “plus” or “minus” disc formats—they're physically different from each other).

Despite looking nearly the same, DVDs are completely different from compact audio discs.  The diameter (size) of the disc may be the same, and it may have the same shape, but different laser technology is employed (a much smaller beam, writing more data into the same available space, and multiple layers within the same disc).  You cannot play a DVD in a compact disc player, though many DVD players are capable of playing DVDs and audio compact discs (ones which have a multi-read unit).

Data formats

Data can be stored on DVDs for different purposes and in different ways.

Most movie discs (feature films, etc.) are in the DVD-Video format, though there's a different DVD-VR (video recording) format that's commonly used on machines that allow you to record your own video discs.  Many DVD players are only designed to play movie films, and will only play DVD-Video format discs.

There's a DVD-Audio format for music discs, it's allegedly a large improvement on conventional audio compact discs (better quality and greater capacity).  Not to be confused with a video DVD that has music videos on it—it's a type of DVD format, not a description of the sort of films on a disc (movies, music, documentaries, etc.).  DVD-Audio is an uncommon format and few players support it.

And then there's different filing system formats used on DVD-ROM and DVD-RAM discs for computer data.

These are all different ways of storing data onto a disc, whichever type of disc they are.

DVD-5/9/10/14/18 (disc capacities)

On most players you'd have to flip dual-sided discs over to use the other side (I've yet to see a machine that can read from both sides of the disc, though it's not impossible).  But you don't need to do anything to manage playing dual-layer discs, the player reads through one layer to see the other.  These are all standard disc capacities, and should work on all machines, though some might not bother to support the unusual ones.

Recording modes

There are several recording modes available on most DVD recorders, and they affect several things, with each mode changing one or more parameters:

For instance, one of my recorders has the following modes:

Only the first two modes are on a par with normal television picture quality, the last two are sub-standard.  The EP mode is even somewhat worse than VHS tape, and the SLP mode is similar to LP mode VHS.

DVD plus, minus, and RAM disc types

Those disc formats (DVD-R, DVD-RW, DVD+R, DVD+RW, DVD-RAM) are all different types of recordable discs.

To play any of them back requires a player that supports those formats (many don't).  They're all different from the format used for the discs you rent or buy from the movie houses (DVD-Video), and not all home DVD players support them (any, or all, of these formats).

Studios may have their discs “pressed”, similar to how the old vinyl records were pressed, as a fast method of mass production (instantly replicated, rather than spending time writing to the disc in a linear manner—writing from the start of the recording to the end, sequentially).  These are produced to one of several DVD-Video standards (which work in nearly all players—they should work in all players, but not all players are built properly).  The method the information is impressed onto the discs is quite different than self-made ones.

There's no simple answer as to which writeable disc format is best.  I, generally, find plus discs are better.  They're faster to read and write to, and more reliable, on equipment that supports them.  But some equipment only supports minus discs, or supports them better than plus discs.

Disc speeds (1×, 2×, 4× etc.)

There's a standard speed that discs spin at (1×).  Although the disc speed can vary as the laser moves away from the hub (so that there's the same amount of disc surface passing by the laser as it moves towards the edge), the spin speed (for the entire variation used) has a “normal” or “standard” speed that they're played at when you watch DVD videos (at 1×).

Some discs can be spun faster while you're writing to them, to finish the job in less time.  Naturally, the disc must be rated to support this (a 2× disc can be burnt to at approximately twice the normal speed, and so on), and the burner must support faster speeds, too.

Writing to a disc involves heating a portion of the surface with a laser to the “Curie” point, where you can change its properties magnetically.  To heat it sufficiently, enough power, for a long enough period, must be applied to the surface.  If you shorten the time period (by spinning the disc past the laser quicker) you have to increase the heating power of the laser, to get the same effect.

Naturally, you need a laser that can be suitably adjusted (a drive that supports writing at different speeds), and discs that respond correctly to being written to with different amounts of power (discs rated for use at faster speeds).  For computer-based disc writing, the burning software will determine what speeds the drive and disc can be used at, automatically, and you can decide which to use.  For other live systems, such as DVD video recorders, they'll automatically use the disc at the speeds best suited to what it's doing, according to the rating of the disc.

All discs, no matter how they're recorded, are played back at the standard rate when playing back a disc to watch on your television.  And the high speed picture search functions don't spin the disc faster, they skip across it in steps.  So beyond how well a disc was recorded, the disc's speed rating won't have any bearing on how the discs plays back (the speed rating's only a recording speed issue).  Although it might be suggested that the discs that're able to be recorded to at higher speeds might be better quality discs, and it is well-known that most disc writers do a better job when working at slower speeds (most burning software allows you to set a limit to the speed that it will burn at).

That × symbol is the multiplication sign, not a letter x.  It refers to how much faster the spin speed is than the normal speed (normal speed, twice as fast, four times as fast, etc.).

Is it disc or disk?

Floppy disks are the only things (that I know about) that spell disc as “disk” (it's an abbreviation of diskette, actually), everything else to do with a circular object is a disc (e.g. Compact Disc, or Digital Versatile Disc).

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