Thursday, January 22, 2004

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Backing up your legally owned DVDs - a 'how to' guide

A brief introduction to the DVD format

Please sir, can I have some more? Certainly Oliver, how many gigabytes would you like? I am of course talking about data storage space. Once upon a time, having the ability to backup 650mb of data to a CD was a feat met with gasps of awe. Since then the emergence of the digital versatile disk (or DVD) has upped the ante along with the storage capacity possibilities, quite frankly making the trusty CD writer look like a bit of a lightweight. It is now feasible to write up to a whopping 9.4 gigabytes of whatever takes your fancy to a single CD sized disk providing you have the right hardware.

At a glance it's difficult to tell the difference between a CD and a DVD, though judging this particular book by its cover would be highly misleading. Storage capacity represents the most notable distinction between the comparatively miniscule CD and the mighty DVD. Both formats store data within imperceptibly tiny grooves aligned so as to spiral around the surface of the media. Within these grooves are found pits and bumps representing the ones and zeros of digital information that are read by CD/DVD drive lasers. DVDs are able to store many times more data than CDs owing to the smaller pits and a tighter track spacing of their structural makeup, the landscape of which is scanned by smaller laser beams than those of a CD drive. Without going into great detail, your CD drive, unless it happens to be a CD/DVD combo drive, will never be able to read DVDs because their larger laser beams cannot interpret the smaller surface data structure of DVDs. No matter how many internet rumours you have the misfortune to stumble across relating to this, it cannot be done, no way, no how; if you want to read DVDs you will need to buy a DVD-ROM drive.

A comparison of the many variants

DVDs can accommodate up to four layers of data, two on each side of the disk, in comparison to the single layer offered by CDs. To be able to read the various layers of information, DVD drive lasers alter the intensity of their focus to probe deeper into the disk - each change of focus is known as a 'layer switch'. Note that because the lasers in DVD players and DVD-ROM drives are suspended in a fixed position it is necessary to manually flip over double sided disks in order to access all the data. The possibility of utilising up to four layers of information on a single disk has resulted in the development of four different types of DVD, each distinguished by their data capacities.

Single sided, single layered disks can hold a maximum of 4.7 GB worth of data, while single sided, dual layered disks can hold roughly 8.5 GB. Double sided, single layered disks have the potential to store 9.4 GB worth of data, whereas double sided, dual layered disks can contain approximately 17 GB. At present it is only possible to create DIY DVDs containing no more than 9.4 GB worth of digital delicacies because there are no DVD writers on the market which are capable of burning dual layered disks. To give you a rough idea of how long you can expect to have to twiddle your thumbs waiting for a full DVD to be written, a 2x writer can record a full 4.7 GB DVD in approximately 30 minutes and a 4x writer would achieve the same task in approximately 15 minutes. From these figures it is clear that CD and DVD drive speeds cannot be directly equated; a 2x speed DVD writer works much faster than a 2x CD writer.

DVDs come in three flavours; DVD-Video, DVD-Audio and DVD-ROM. DVD-Video disks contain a combination of audio and video content and are used to store the movies you can buy in stores or rent from Blockbuster et al. DVD-Audio disks, although far less common in mainstream retail outlets, are used to store high fidelity, multi channel stereo music. DVD-ROMs are computer compatible disks used for data archival purposes, much like the CD-R format only with greater scope.

To further complicate the state of affairs, there are three DVD recordable formats; DVD-RAM, DVD-R/DVD-RW and DVD+R/DVD+RW. At present they are to be considered competing formats as a de facto standard has yet to be decided upon. Unsurprisingly this creates all kinds of quandaries for the consumer, not least the fact that the various formats are incompatible with one another - a single format DVD-R/RW drive is incapable of writing to DVD+R/RW disks and vice versa. Also, there's a good chance that your home made DVD movies will not work in your standalone DVD player. To avoid such dilemmas you can either buy a writer which supports multiple formats (commonly known as a combo drive), or you can patiently bide your time until one or the other drive/media rises victorious from the ashes of the format war before taking the plunge.

DVD-RAM disks have more in common with hard drives than with CD-R or CD-RW disks as they can be written to up to a hundred thousand times and do not need to be reformatted before use. They can store up to 9.4 GB worth of data on a double sided disk, though because most DVD players and DVD-ROM drives do not support them, DVD-RAM drives aren't worth considering unless your requirements do not extend beyond backing up computer data and re-using that data on a single computer or multiple computers which have DVD-RAM drives installed. My prediction is that the DVD-RAM format will disappear into obscurity in the near future leaving the pluses to do battle with the minuses.

The DVD-R format, devised by Pioneer, has the advantage over DVD-RAM that it is supported by most DVD players and DVD-ROM drives. DVD-R disks are capable of storing 4.7 GB worth of data per side yet they can only be written once. Keeping it within the family, DVD-RW disks can be written up to a thousand times and can also contain 4.7 GB of data per side. Likewise they are compatible with most DVD players and DVD-ROM drives. DVD-R media can additionally be divided into DVD-R(A) disks which are designed for professional authoring, and DVD-R(G) disks which are intended to be used for general use.

Of the three formats, DVD+R is the only one to offer complete compatibility with existing DVD players, and because it is backed by a number of the most important names in the computer industry (Dell, Yamaha, Mitsubishi, Philips, Ricoh, Sony, Compaq, Hewlett-Packard and Sony) it has a good chance of outliving the competition to become 'the one' - I'm sure The Highlander would be proud. DVD+R drives are not able to read or write to DVD-RAM disks but gain ground because they are backwards compatible with CD-R and CD-RW disks. The usual 4.7 GB per side capacity rule applies and they can be re-written up to a thousand times.

It's worth noting at this point that older DVD players cannot play any kind of rewritable disk so if you intend to use this type of media you will have to either invest in a new DVD player or only play back rewritable disks in your computer's DVD drive. The newer your DVD player, the better chance it has of correctly reading your disks irrespective of the format they take.

Making your DVD player region free

Like Bill Gates, motion picture studios are evil, which is why they try to insist that you only buy DVDs from within the same geographic region in which you bought your DVD-ROM or DVD player. They do try to defend their motivations for doing so with a number of plausible sounding justifications i.e. because movies are released at the cinema at different dates across the globe, DVD release dates have to be carefully regulated so as to ensure that people in the UK, for instance, cannot buy a movie DVD while that same movie is still being shown at the cinema, though I still think my original explanation is more apt. ;)

Working in cahoots with the naughty people in the movie biz, the DVD Copy Control Association assert that anyone wanting to manufacture a DVD-ROM drive or DVD player must implement region code restrictions into their hardware. This can be changed a maximum of five times by the user and a further four times if the unit is returned to the manufacturer.

When this system was first introduced it was met by a public backlash; unsurprisingly many people were not prepared to have their consumer rights compromised for the sake of helping the movie industry to line its already bulging pockets. It was soon discovered that it was possible to circumvent this protection to force DVD drives/players to play all DVDs regardless of where they originated, hence the region-free DVD player was born. The code which stipulates which DVDs can be played in a particular DVD player is stored on a chip very similar to that of a motherboard BIOS chip, and as a result they can be 'flashed' to change the way they function in an identical fashion.

To make a DVD player region free you have to update the player's firmware with a patched version. Your first task is to identify the model number of your DVD drive and find out if it is region locked - you can do this using a utility known as Drive Region Info. It's very unlikely that your drive will already be region free, but if Drive Region Info reveals that it is, you obviously do not need to alter your firmware. Once you know the model number of your drive you can download patched firmware for it from The Firmware Page and apply it in the usual way (as described in the misc. section of the FAQ). As always, remember to heed the warnings found in the readme.txt file of the relevant 'flashkit' archive and follow the instructions to the letter, otherwise you could do permanent damage to your hardware. When you reboot your computer, load Drive Region Info again to check that the changes have taken effect.

Creating data DVDs and extracting movie DVDs to your hard drive

Creating your own data DVD is accomplished in exactly the same way as you would write a CD-R/RW. In Nero, for instance, you would select 'new' from the 'file' menu and then choose the DVD option from the drop down selection box before clicking 'OK'. Files can be added to the compilation by dragging and dropping them into the empty pane below the new DVD title. Once you are ready to commit your choices to disk you can write the DVD by clicking on the 'write' dialog box, making sure you check the 'finalize' option if you do not wish to add anything to the DVD at a later date.

Unfortunately Nero is incapable of backing up commercial, copyright protected data, movie or audio DVDs, and similarly trying to merely copy the files to your hard drive will achieve very little. Game copyright protection mechanisms have already been covered elsewhere on this site so should be familiar territory. Movie copyright protection on the other hand may be new to you so we will briefly look into this before moving onto discussing possible ways to get around it. Nearly all movies worth watching are encrypted using the content scrambling system (CSS) so cannot be copied using standard CD/DVD writing tools, or simple copy and paste techniques. For your DVD player to be able to access these disks at all, the key which decrypts the scrambled data before streaming it to your TV or computer monitor has to be provided alongside the 'lock'. To prevent people from copying protected disks these keys are kept well hidden in the normally inaccessible lead-in area of the disk. Whenever you try to copy such a disk you get the scrambled data, but not the key which allows you to make sense of that data. As a result, errors are spat out at you whenever you try to play back the protected content from your hard drive i.e. the movie .VOB files which contain an amalgamation of video, audio and subtitle streams.

I realise warning you what not to do isn’t a great deal of help on its own, so now would be an opportune moment to tell you what you should be doing. Downloading DVD Decrypter would be an excellent place to start - this will provide the means to create an image of a protected DVD which can be stored on your hard drive for further manipulation or play back. It's free and luckily is no more difficult to use than Clone CD, a program you are perhaps more familiar with. Let's get to work. Run the program and insert the DVD you wish to decrypt into your DVD drive. DVD Decrypter should detect the disk and locate the most suitable drive or partition on which to store the extracted data i.e. the one with the most free space available.

I should point out at this stage of the proceedings that because a movie extracted to a single ISO file will consume upwards of 4 GB of hard disk space, the partition you intend to store the file on must have been formatted to use the NTFS file system. This is because FAT32 doesn't support files of this magnitude. If you don’t have an NTFS partition available and do not wish to convert one of your FAT32 partitions you will have to use the 'file' rather than the ISO output option of DVD Decrypter (files contained on DVD-Video disks cannot be greater than 1 GB in size), but more of that later.

DVD Decrypter will auto-magically select all the constituent parts of the movie, leaving you only the task of prodding the DVD to hard drive transfer button in the bottom left corner of the application GUI. Within 30 minutes, depending on the speed of your computer hardware and the length of the movie, the transfer of the movie VOB files to your hard drive will be complete.

These can now be played using a range of software DVD players, the best of which are thought to be Win DVD and Power DVD. In Power DVD you can do this by pressing control and O to access the open menu followed by selecting "open DVD files on hard disk drive". Finally from within the subsequent dialog box choose the VIDEO_TS.IFO file extracted by DVD Decryper (IFO files contain navigational information used by your DVD player to jump between chapters etc).

To achieve the same thing in Power DVD you first have to create a folder on the root of your hard drive called VIDEO_TS (note this is case sensitive) as you would find on the original DVD and move all the extracted files into it. To play back the movie you would then click on the options button and select the hard drive where the files are stored.

If you'd rather turn your DVDs into ISO files and play them using a CD/DVD mounting tool such as Daemon Tools then that is also possible with DVD Decrypter. In this case you would select ISO (the 'read' variant obviously) from the 'mode' menu before hitting the start button.

As you've probably gathered by now this is a great way to backup your DVD movies if you aren't lucky enough to own a DVD writer, assuming you have plenty of spare hard drive real estate that is. If you have got a DVD writer you might like to learn how to go about writing your extracted files to a blank DVD (or two). This will be our next task. Because DVDs come on either dual layered 8.5 GB disks (DVD-9) or single layered 4.7 GB disks (DVD-5) they cannot all be duplicated in the same way. The most notable stumbling block is the fact that no DVD writers exist that can write dual layered disks, so if you want to copy a DVD-9 disk you have to either use two recordable DVDs, down sample the DVD to make it fit on a single disk, chop out the extra features to save space and then write it to a single disk or use a combination of these methods.

Backing up DVD-5 and DVD-9 disks to recordable DVDs

Backing up a DVD-5 disk is a cinch as it is possible to create a 1:1 copy using only DVD Decrypter. Assuming you have created an ISO image of the DVD you wish to backup using the methods described earlier, all you have to do to write the file to a recordable DVD is to select Mode > ISO > Write from within the DVD Decrypter interface, insert a blank disk and hit the hard drive to DVD transfer button.

The trouble is, most modern DVD disks are of the DVD-9 variety so unfortunately they cannot be backed up using this method. It would seem that there are nearly as many methods to backup such disks as there are DVDs. Everyone has their own favoured means and it's difficult to say outright which, if any, is superior because they all have their advantages and disadvantages. Perhaps the most sensible thing to do is choose the one which suits you and not get too caught up arguing your case for or against using one piece of software or the other... which is exactly what I'll proceed to do now because I have no self control. ;)

The process can be as easy or difficult as you want it to be - some DVD copying guides will span many pages and list up to a hundred time consuming steps which you must follow to the letter in order to produce a working backup. Those people who put their faith in such methods rationalize that only by doing this can you create perfect copies indistinguishable from the original. They may well be right if you're the type of person who can spot a needle in a haystack from a hundred yards while wearing sun glasses during an eclipse, but for everyone else, the quick and easy methods will suffice. Also keep in mind that as time goes on, more and more one-click DVD backer-up-erers will appear on the market; the extraction/writing process will become more refined and there will be even less evidence to support doing things the hard way (as I type, the people behind the award winning Clone CD are working on a DVD hybrid which should be the answer to many frustrated DVD devotee's dreams). Quality issues aside, of course there will always be people who will continue to do everything manually using a number of different programs because they think it makes them look l33t (that's quite clever with computers for anyone who doesn't speak hacker).

One of my favourite methods which involves a few more steps than your average idiot-proof, Clone CD style tool is to extract the movie using DVD Decrypter and then write it to a single DVD using Pinnacle's Instant Copy (he says backtracking slightly from recommending one click solutions). This method allows you to cram a full DVD-9 movie onto a single recordable DVD, although it does detract from the video quality of the original movie somewhat.

First of all, extract the movie data from the DVD using the Mode > File method, select all the files from within the 'edit' menu and begin transferring them to your hard disk using the transfer button in the bottom left hand corner of the DVD Decrypter GUI. Once the task is complete it's time to whip out Instant Copy and set it to work. From within the 'source' menu option choose hard disk, select the folder where your movie data files are stored and locate the VIDEO_TS.IFO file. Now select the destination DVD writer drive and click on the DVD tab. Change the copy method to 'Customized Resize' and the preferred destination to DVD and press the start button.

You will now be required to configure the video size settings. The challenge here is to reduce the video size and hence the file sizes so that they fit on a single recordable DVD. You can either reduce the video size of the main movie and the extras indiscriminately or you can reduce the video size of the extras while maintaining the video size of the main movie; it's all about compromising to find the right balance. Look at the contents box and you will see a folder labelled 'Video Tracks'. If you click on this, a list of all the components of the movie will appear (you will easily be able to recognise the main movie as it will be many times longer than the supporting files). Select each of them one by one and under the 'video' tab drag the slider to resize the video accordingly.

The options under the 'audio' tab allow you to selectively remove audio tracks (if you only speak English you might like to remove the multi-language support entirely), and the 'subtitles' tab provides the means to hack out the subtitles to recoup even more space - no great loss unless you suffer from hearing difficulties of course. When the data size bar turns green (to indicate that the files are small enough to fit on a single recordable DVD) and you're happy to commit your amendments to file, click the OK button to begin converting the movie. The process will take anywhere up to six hours to complete so you might want to set it up to work over night or while you're out at work, school or wherever (if you're not prepared to wait this long you might like to use a program called DVD2One instead of Instant Copy - the quality of the resulting movies isn't as good, but you can extract and write a DVD in under an hour). Once complete, a dialog box will appear requesting you to insert a blank DVD. Do as it says and our work here is done.

The one click method

All in one conversion tools that claim to create perfect DVD backups are nothing new, though when it comes to the crunch, many of the authors of such programs are exposed as blatant charlatans as they do nothing of the kind. Instead they produce DVD rips in SVCD or DivX format without the need for a DVD writer. These kinds of rips would be perfectly acceptable if what you require are reasonable quality movies in a format small enough to fit on a CD-R, however, what I object to are the false claims which typify the spiel of far too many DVD software authors. Separating the hype from the truth can be a time consuming process, though one technique I often use is to quickly scan through the introductory text on DVD software web sites to pick out the text which has obviously been translated from Korean, Chinese or Japanese using Babelfish. This may sound totally ethnocentric and narrow minded, yet you'd be surprised by how many frauds can be exposed by this simple method. Besides, if you've created a quality product to be proud of, you don't present it to an English speaking audience using sloppy, grammatically incorrect Engrish. If your English is terrible, but you're a talented programmer, for your sake, get a native English speaker to help you - otherwise your work will be dismissed by prejudiced people like me even if the code is top notch. ;) If your English and your programming is terrible, for my sake, don't bother at all.

Finding the real deal is a rarity - DVD X Copy is probably the closest you'll get. It doesn't create copies which are identical to the original movie, but it comes so close it's not worth splitting hairs. Because DVD X Copy has been deemed by the Motion Picture Association of America (MPAA) to be in breach of the Digital Millennium Copyright Act (DMCA), 321 Studios, the authors of DVD X Copy, have had to implement a number of conciliatory features into the program to sidestep potential legal battles. What this means for the consumer is that the movies created by DVD X Copy have to be tampered with, which brings into question just how "perfect" the results truly are. Firstly, the program stamps its own copyright protection onto your movies to prevent further duplication. Secondly, a digital watermark is embedded into your movies so as to aid identification of the licensed owner of the software used to create the duplicate. Finally, a disclaimer is appended to the beginning of all movies to inform viewers that the disk is a backup copy intended for personal use only.

"Personal use" is the key term here; the DMCA states that the owner of an original DVD is perfectly entitled to create a single backup copy of that disk providing the duplicate is only watched in private and is not distributed either freely or for profit. For the MPAA to obtain a court order insisting that the product be withdrawn from the market they would have to prove that DVD X Copy is being used first and foremost as a piracy tool; a task they are currently working on. At least for now, consumers can continue to exercise their right to backup their legally owned DVDs safeguarded by their 'fair use' agreement.

Legal wranglings aside, DVD X Copy provides the means to backup almost identical copies of DVD-5 or DVD-9 disks including menus, trailers and special features. DVD-5 disks can be backed up in their entirety to a single recordable DVD, whereas two disks are required to back up a DVD-9 movie assuming you do not want to lose any of the accompanying extras. If saving a recordable disk is a higher priority you can have DVD X Copy remove all such material leaving you with only the main movie which will comfortably fit on a single recordable disk. When you first insert the DVD you intend to copy, DVD X Copy will inform you whether or not it will fit on a single disk. If it won't, the main movie is copied to the first disk and the extras are stored on the second disk, while particularly long movies are spanned across two disks. How the second disk begins playing when inserted is your decision - it can either begin instantly or be selected from the main menu. The exact point at which longer movies are split is initially decided for you, yet you always have the option to alter the default selection if it does not suit your requirements.

When you're happy with your choices you can press the 'copy now' button to begin transferring the files to your hard drive. If you have a separate DVD-ROM drive and DVD writer you may like to use the extremely useful 'output disk is ready' feature, which allows you to insert a blank DVD into your writer at the same time as you insert the source disk and have DVD X Copy begin writing to it once the creation of the temporary files on your hard drive is complete. Otherwise you will be expected to baby sit the process until the extraction is complete and then switch disks.

So there you have it; the ability to create one click, hands free DVD backups is now within reach. The decision to use this method should ultimately be based upon weighing up the advantages of speed and simplicity against the ability to have complete control over your backups. Personally I think it's a small sacrifice to make, and in any case since you should only be making copies for personal use, you only have yourself to please. If your backups are good enough for you, feel free to ignore the the ultra-picky elitists - most of them are just grumpy because people are less impressed by their skills now that your average silver surfer can achieve the same results with minimal technical know-how. ;)

Sunday, January 18, 2004


How do I make payments online without disclosing my credit card details to each retailer?

The most convenient and secure way would be to use a service such as Pay Pal (currently the most widely used online payment system). The idea is that you create a free account, register your credit or debit card with them and then whenever you wish to purchase something online, you provide the retailer with your Pay Pal ID rather than your credit card details. Obviously the less people who have a record of your credit card details, the less likely you are to become a victim of credit card fraud.

Furthermore, you can use your account to pay individuals who do not have access to an online credit card transaction system - eBay members who are not selling goods on behalf of a registered commercial enterprise for instance.

Although I've only ever had good experiences with Pay Pal, lots of other people haven't been so lucky, so make sure you do your research before signing up. For more information refer to No Pay Pal or Pay Pal Warning.

Other companies offering similar services include: Fire Pay, No Chex, Instabill, CC Now and Amazon. I can't personally endorse or admonish any of these unfortunately since I've never used them, however, a good place to find impartial reviews would be the online bill payment section of Epinions.

Sunday, January 04, 2004

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How can I repair stuck movie frames?

You can use either AVI Defreezer (which doesn't appear to have a home page associated with it) or DivX Anti Freeze. AVI Defreezer fixes troublesome movie files by editing them and DivX Anti Freeze provides a background workaround without tampering with the original files. The latter 'patch' requires you to do nothing more than install the program so don't waste your time looking for its GUI - it doesn't have one.

To fix files using AVI Defreezer you will first need to find out exactly which frames are frozen - this detective work can be carried out using Virtual Dub. What you need to do is scan through your movie using the tracking controls until you reach the point just before the frozen frame occurs and press the play button. Wait until Virtual Dub displays an error message, click on the 'previous keyframe' button and note down its frame number (see the status bar at the bottom of the program). Now click on the 'next keyframe' button and again note down the frame number.

Open AVI Defreezer and enter these frame numbers in the boxes provided in the order they appeared in the movie i.e. chronologically and click on the 'add frames' button. Repeat this procedure for all the frozen frames, choose a new filename for the repaired file and then click the 'defreeze' button.

Now when you open the new movie file it should play smoothly through the previously frozen scenes, although some errors may still be evident - these cannot be fixed using AVI Defreezer, but can be cut out completely using Virtual Dub if they bother you that much.