DVD copy protection is a broad term that covers various methods of copy protection for DVDs. These methods include DRM, CD/DVD-checks, Dummy Files, over-sizing and over-burning the DVDs, illegal table of contents, physical errors or bad sectors.
Different types of DVD copy protection
There are three types of copy protection that are used on commercial pre-recorded DVD discs. These are Analog Protection System (APS) scrambling, Content Scramble System (CSS) encryption, and a system involving corrupted disc structure. Recordable DVD discs are also sometimes copy protected using Content Protection for Recordable Media (CPRM) encryption. The following part will illustrate these schemes in great details.
Analog Protection System (Macrovision)
The Analog Protection System, popularly known as Macrovision after the company that developed it, is a protection system that is applied to the composite analog video signal coming out of DVD players. By manipulating the signal level of the composite video, Macrovision fools the automatic gain control of most video recorders resulting in annoying shifts in color and brightness in the recorded video.
Macrovision can be defeated by passing the composite video signal through a hardware device that restores the proper video signal levels. With the demise of analog video and the widespread availability of digital decryption tools, Macrovision protection has largely become irrelevant. Macrovision Corporation renamed itself Rovi and now promotes other copy protection technologies.
Content Scramble System (CSS) Encryption
CSS is an encryption system that is the main copy protection scheme used on pre-recorded DVD discs. CSS utilizes a proprietary 40-bit cipher that is used to encrypt the data stored on the DVD disc. When the disc is inserted into a player or computer, a series of “authentication” handshake key exchanges occur between the DVD drive and the player software. At the end of the “authentication” process, the drive allows access to the encrypted DVD data and the player can use the key it has obtained to decrypt the DVD data and play the disc.
Many DVD drives have a tendency to completely lock out access to an encrypted disc until the drive has been “authenticated”. In addition, many DVD drives will refuse to complete the “authentication” process and provide a decryption key if the disc and drive are not from the same region. Both of these situations can cause strange behavior and odd error messages on computer systems.
DVD Disc Corruption
After the CSS protection system was cracked, the movie industry looked for a alternative copy protection scheme that would be compatible with the large number of existing DVD players in the marketplace.
Borrowing a (failed) technique from the video game industry, they settled on a scheme in which portions of DVD discs are deliberately mangled in such a way as to render them unreadable. When the disc is played, these corrupted areas of the disc are skipped. When the disc is copied sequentially, however, these corrupted areas cause the drive to hang up and get stuck.
This copy protection scheme has been marketed under a variety of names, including ARccOS (by Sony), RipGuard (by Rovi), Disney X (by Disney), etc. For cost and convenience reasons, it is not applied to all commercial DVD releases.
DVD disc corruption is a nuisance, but most of the more sophisticated DVD copy tools can handle it. Some tools maintain a database of corrupted areas on DVD discs that contain corruption, while other tools attempt to analyze the DVD structure to find areas of the disc that are never accessed.
Related article: Understand DVD Copy Protection | DVD Copyright Laws | Play DVD without Region Code
Content Protection for Recordable Media (CPRM)
CPRM is a copy protection scheme that is used for Secure Digital (SD) memory cards and recordable DVD discs, including DVD-R, DVD+R, DVD-RW, and DVD+RW discs. Special CPRM-compatible recordable media are required, with each disc including a unique Media ID inscribed as a bar code in the inner hub area.
When a CPRM-compliant recorder detects compatible media, it uses the unique Media ID on the disc to encrypt the data it records to the disc. The recorder will also write a block of data called the Media Key Block (MKB) which is used to decrypt the disc. If the disc is copied, the Media ID on the new disc will be different and the recorded data will not decrypt correctly.
CPRM protection has largely been restricted to the Japanese market, where it is called “Copy Guard” and used to protect broadcast HDTV programs that include a special Copy Guard flag. Japanese-market recorders that record that program are required to include CPRM protection. Depending on the Copy Guard instructions, a limited number of copies of the CPRM disc data may be permitted.
The CPRM system involves something called the Cryptomeria or C2 cipher, which uses a 56-bit key and 64 byte blocks. The majority of the cipher is published openly, but a proprietary “S-box” portion of the cipher is provided only to CPRM licensees. The licensing organization is called the 4C Entity, whose membership includes IBM, Intel, Microsoft, Panasonic and Toshiba.
A cryptanalysis of the C2 cipher was published in 2009 and CPRM was partially cracked in late 2009 using a crowd-sourced brute-force attack, and a set of decryption tools for Windows based on the key from this crack was distributed over the internet.
Original source:
http://www.miraizon.com/support/info_copyprotection.html
Best software to remove DVD copy protection
Before paying money for some third-party DVD Ripper software, some people will first turn to find some free DVD Ripper software to fix this issue. However, you may be disappointed to find a lot of them such as Handbrake, Format Factory, VidCoder, etc only handle DVDs without copy protection. Others like MediaCoder only limited to handle early version of CSS – protected DVDs.
If you are looking for a powerful program to bypass all DVD copy protection we highly recommend Pavtube DVDAid to you. The program is equipped with a powerful built-in disc decrypter to assist you to automatically bypass up to 14 types of DVD copy protection including Region code, RCE, key2Audio, UOP, CSS, Macrovision, FluxDVD, Protect, ARccOS, AACS, BD+, ROM Mark, BD-Live, etc. Besides that, it also keeps constant update with perfect support for the new DVD encryption used on many recently released DVD movies. The program has full loading support for copy protected DVD disc, Video_TS folder and IFO/ISO file. After the copy protection is removed, you can then freely rip the content on the DVD disc into any of your desired file formats and also hot devices and applications preset profile formats for convenient playing, sharing or backup.
Other beneficial functions and features of Pavtube DVDAid
– Automatically select the main DVD title for you
– Select desired subtitle language and audio track from internal DVD movies
– Customize output profile parameters to get better output video and audio quality
– Enable forced subtitles to disable the traditional subtitles while still preserving the subtitles that translate foreign language speaking parts.
– Add external subtitle to DVD when the foreign language DVD movie do not contain any language subtitles you understand.
– Edit DVD movies by trimming unwanted parts, cropping out black bars or unwanted area, add video/image/transparent text watermark, apply special effect, change video color effect, remove/replace audio in DVD video, etc.
– Available on both Windows and Mac (get Pavtube DVDAid for Mac) platform
How to Remove Copy Protection from DVD Movies?
Step 1. Import Copy-protected DVD movies.
Insert DVD disc into optical drive of your computer. Launch the best DVD copy protection removal software on your computer, on the main interface, click “File” > “Load from disc” to import copy-protected DVD. You can also add ISO image or DVD folder as target files.
Tips: Once the DVD is completely loaded, the main title will be checked automatically. From the drop-down list of “Subtitle” or “Audio” select your desired subtitle language or audio track.
Step 2. Select Output Format.
Navigate to the “Format” bar drop-down list, here, you can choose the output file format according to your own needs. You can either output a popular file format such as AVI, WMV, MP4, MKV, MOV, etc or devices (Apple, Android, Microsoft, etc) preset profile formats. Or a full disc copy or main movie copy of your DVD movies.
Step 3. Start DVD Copy Protection removing process.
Tap Browse button to set destination folder (hard drive or device) and then click right-bottom “Convert” button to start to remove DVD copy protection.
When the ripping process is completed, you will have no problem to play non-protected DVD movies on any device as you like.
