WO2006005356A1

WO2006005356A1 - Data carrier and method for manufacturig a copy-protected data carrier

Info

Publication number: WO2006005356A1
Application number: PCT/EP2004/007603
Authority: WO
Inventors: Holger Beisheim
Original assignee: X-Protect Gesellschaft Mit Beschränkter Haftung
Priority date: 2004-07-09
Filing date: 2004-07-09
Publication date: 2006-01-19

Abstract

Copy protection of DVDs by insertion of defective blocks of data in data portion. The defective areas are marked in the table of contents (TOC) as non-data areas and are hence ignored by entertainment DVD players. However, computer DVD drives are confused by defects and cannot read or copy the DVD. The defects are produced by setting all parity bits in a sector to zero during the DVD mastering process.

Description

Data Carrier and Method for Manufacturing a Copy- Protected Data Carrier

The present invention relates to a data carrier, in particular a DVD, according to the preamble of claim 1 as well as to a method for manufacturing such a copy¬ protected data carrier.

In particular a DVD (digital versatile disc) is to be considered a data carrier of the present invention. DVDs are preferably used as a storage medium for movies, games and the like. There is increasingly the problem that copies can be pro¬ duced very simply and very inexpensively with a corresponding burner or the like, i.e., can be produced, in particular, with a home computer or the like.

WO 01/52255 Al, which forms the stating point of the present invention, dis- closes a data carrier and a method for producing a copy-protected data carrier, wherein defect storage areas are additionally stored on the data carrier. This document does not give any hint how to protect video files.

WO 98/54713 Al discloses a method for copy-protecting a record carrier, wherein the record carrier is provided with a pattern of logical bit errors such that the errors accumulate during de-interleaving to an uncorrectable number of error words. This copy-protection is not suitable for movie DVDs, in particular it re¬ sults in problems during normal playback.

WO 98/52194 Al discloses a method for copy-protection, wherein a small or large number of synchronization and header sections is altered and wherein some user information is stored inbetween. The modified sections renders the user in¬ formation in certain portions on the disc inaccessible and is not copied during typical copying operations. Thus, storing user information between the inacces- sible portions prevents copying the user information to an unauthorized duplicate of the disc. Additionally, when a user wishes to use data stored on the disc, a disc reader optionally determines whether the portions are accessible. If the portions are accessible, the user is prevented from using the data. If the portions are inac¬ cessible, the user is permitted to use the data. This copy-protection is not suitable for movie DVDs due to interruptions during playback with a usual DVD player or the like.

WO 98/03973 A2 discloses a protection against copying. The address labels of specific sectors with informationless content or of subcode data are given differ¬ ent, e. g. zero, address values, which prevent copying CD-ROM discs on a stan¬ dard CD-recorder apparatus. Before the user actually is given access to the digi¬ tal data, a verification process is executed. The presence of at least one of the ad¬ dress labels having said different address value is verified. If the reading re- sponse shows an error, the presence of the different address is detected. This copy-protection is not suitable for movie DVDs.

DE 198 37 809 Cl discloses a method for copy-protection, wherein user data or error codes of data blocks are manipulated and wherein the data block is read with and without error correction and the resulting data are compared. This copy¬ protection is not suitable for movie DVDs or the like.

Object of the present invention is to provide a data carrier and a method for manufacturing a copy-protected data carrier respectively containing at least one video file, so that copying of the data carrier can be prevented in a simple way, or can be made at least much more difficult, but in particular wherein playback with a usual DVDj)layer is possible without any disadvantage for the user... - .._, .

The above object is achieved by a data carrier according to claim 1 or by a method according to claim 12. Advantageous embodiments are subject of the subclaims.

In the subsequent discussion reference is made only to a DVD as mainly pre¬ ferred embodiment of the proposed data carrier. However, the same applies also to other, in particular similar, data carriers.

A basic idea of the present invention is to include an additional copy protection block with defect sectors, preferably a cell, at the beginning of the first video file, so that the DVD can be read by a usual DVD player or the like. In particular the movie, game or the like stored on the DVD can be presented by a usual DVD player without any interruption or disadvantage or the user. But, the video file with the defect sectors cannot be read by a home computer, personal computer or the like as a data file, so that (complete) copying can be prevented.

The incorporation of preferably only one copy protection block in the preferably first video file according to the present invention requires only very little effort and, thus, can be realized easily, but results in a surprisingly effective protection against copying.

Further advantages, aspects and features of the present invention will be ex- plained with reference to the drawing of a preferred embodiment.

Fig. 1 shows a schematic diagram of the file order of a DVD;

Fig. 2 shows a schematic diagram of a video object set;

Fig. 3 shows a schematic diagram of a video object;

Fig. 4 shows a schematic diagram of a possible video file structure; and

- Fig. 5 shows a schematic representation, not to scale, of a^ DVD with an associated DVD player. ^{■ •} - _ -

The DVD-video format specification provides high-quality audio and video in a format supported world wide by consumer, electronics manufacturers, movie stu- dios, video publishers and computer makers. Likewise, the DVD-audio specifi¬ cation is focused on high-fidelity multi channel audio. In the following, the DVD-video format is explained in more detail. However, basically the same ap¬ plies for the DVD-audio format.

DVD-video incorporates video and audio formats from various standards. DVD- video incorporates multi-channel digital audio for compatible digital audio sys¬ tems, and also provides digital or analog audio to support standard stereo audio systems. DVD-video also can be played on compatible computer systems. - A -

DVD players (including software players) are based on a presentation engine and a navigation manager. The presentation engine uses the information in the pres¬ entation data stream from the disc to control what is shown.

Navigation data includes information and a command set that provides rudimen¬ tary interactivity. Menus are present on almost all discs to allow content selec¬ tion and feature control. DVD-video content is broken into titles (movies or other programs) and parts of titles (chapters). For example, a disc containing multiple television episodes could present each episode as a title. A disc with a movie, supplemental information, and a theatrical preview might be organized into three titles, with the long movie title arrayed in chapters. A disc can have up to 99 ti¬ tles, but in many cases there will be only one. This would be straight forward if it were not for the industry practice of calling discs titles.

DVD application data are organized into a complex structure representing the physical location of the data on the disc. Since data may be shared among differ¬ ent titles and programs, logical data structures are overlaid on the physical structure. The logical structures contain navigation information and determine the presentation order of information whicHis independent of the physical order.

The physical data structure determines the way data is organized and placed on the disc. The standard specifies that data must be stored sequentially - physically - contiguous - according to the^'DVD-video physical structure which is very simi¬ lar to-the DVD-audio physical structure. -

Fig. 1 represents the order in which data is stored on the disc. The structure is hi¬ erarchical; each block can be broken up into component blocks, which can be further subdivided.

The primary block is a video title set (VTS), which carries internal information about the titles it contains (menu pointers, time maps, sell addresses, etc.), fol¬ lowed by video object sets (VOBSs) as shown in fig. 2. Since the VTS informa¬ tion applies to all the titles in the set, the titles must contain the same number, format, and order of audio tracks and sub-picture tracks. MPEG-I and MPEG-2 video cannot be mixed within a VOBS. First VOBS may be an optional menu (VTSM), called a route menu, followed by VOBSs that contain the actual title content.

The video manager (VMG) is a special case of a video title set that optionally can contain a main menu for the disc.

Data at the VOBS level include attributes for video, audio, and sub-pictures. The language of audio and sub-pictures can be identified with ISO 639 codes and also can be identified with an extension code as commentary, simplified audio, and so forth. Identification codes are stored on the disc as binary representations of two-letter (lowercase) codes.

Each video object set (VOBS) is composed of one or more video objects (VOBs). A VOB is part or all of an MPEG program stream or the like. Each VOBS contains one or more VOB blocks as shown in fig. 3. A contiguous block contains one VOB in contiguous sectors on the disc. An interleaved block con¬ tains multiple VOBs broken into interleaved units (ILVUs) that are physically interleaved on the disc to enable seamless presentation.

A VQB is made up of one or more cells.-A cell is a group of pictures or audio - blocks and is the smallest addressable chunk. -A cell can-be as short as a second or -as long as a movie. Sometimes cells are also called scenes. Each cell -is further . divided into video object units (VOBUs). A VOBU is the smallest unit of play- - -back. Despite its name, a VOBU does not always contain video. ■ • -- -

VOBUs are broken into packs of packets. The format of packs and packets is compliant with the MPEG program stream standard. Each pack (sector) consists of 2048 user or data bytes.

On top of the physical data structure sit the data and file formats. They are gen¬ erally similar for DVD-ROM and the various writable versions, with minor dif¬ ference for writable discs to deal with error correction and rewriting of data.

Each user sector (pack) of 2048 bytes is scrambled with a bit-shifting process to help spread the data around for error correction. 16 extra bytes are added to the beginning: 4 bytes for the sector ID, 2 bytes for ID error detection, 6 bytes of copy right management information, 4 control bytes at the end for EDC error correction. This makes a data sector of 2064 bytes. These 16 extra bytes of each data sector are also called sector control data.

Each data sector is arranged into 12 rows of 172 bytes and the rows of 16 data sectors are interleaved together (spreading them apart to help with burst errors) into error correction code blocks (192 rows of 172 bytes) for each of the 172 columns of the ECC blocks, a 16-byte outer-parity Reed-Solomon code is calcu¬ lated, forming 16 new rows at the bottom. For each of the 208 (192 + 16) rows of the ECC, a 10-byte inner-parity Reed-Solomon code is calculated and appended. The ECC block is then broken up into recording sectors by taking a group of 12 rows and adding one row of parity codes. This spreads a parity code apart for further error resilience. Each recording sector has 13 rows (12 +1) of 182 bytes (172 + 10).

Each recording sector is split down the middle, and 1-byte sync codes are in¬ serted in front of each half-row. This results in a recording data unit of 2418 bytes. The data unit is processed with 8/16 modulation (doubling each 8-bit byte to 16 bits). This modulation is sometimes called EFMPlus. Thus, a physical sec- - tor of 4836 bytes is created, which-is written out row by row to the disaas chan¬ nel data.

.The writable media sector size or user is 2048 bytes. These- bytes can be -en¬ crypted using a title key (CSS), which is stored in the extra 6 bytes of the copy right management information. However, theses title keys and the decryption have already been published on the internet and are known. Therefore, does not exist a simple and effective possibility to prohibit copying of DVDs by home computers, personal computers or the like using usual burners or the like.

For further details regarding the data structure of a DVD, "DVD Demystified" of Jim Taylor, second edition, MacGraw-Hill, ISBN 0-07-135026-8 is herewith in¬ corporated as reference and additional disclosure.

A VOB or a cell thereof as described above forms a video file in the sense of the present invention. In particular, the first video file according to the present in- vention includes a first or a main part of the main content of the DVD, such as a (main) movie, a video sequence of a game, an audio track or the like.

Fig. 4 shows a preferred example of the structure of a video file according to the present invention. The video file contains a sequence of navigation sectors, video sectors, subtitle sectors, and multiple audio sectors. Usually, the video file con¬ tains audio signals for different languages, in different formats and/or for differ¬ ent audio systems in different audio sectors.

According to the present invention, one cell is additionally inserted at the begin¬ ning or at any other suitable location of a usual video file, in particular at the be¬ ginning of the first video file, as described above. This additional cell - in the present example sectors 1 to 1.999 - is preferably added during the generation of the physical data structure, i. e. when generating the video object set and video objects, in particular in a so-called authorizing studio or the like.

The additional cell preferably forms a so-called black screen, i. e. is not dis¬ played by a DVD player. This is achieved in that the presentation or navigation information on the DVD is adapted such that the DVD player does not present this additional cell. In particular, a respective program- control block does not point to this additional cell or is-τespectively adapted by the authoring studio or the like so that this additional cell is not presented by the DVD player. Prefera¬ bly, the control data or VTSI are generated^"by^~the authoring studio and contain-' the respective navigation or presentation information for the DVD player, such that the additional cell is not presented.

The additional cell preferably contains 50 to 5.000 sectors, more preferably 1.000 to 2.000 sectors. Preferably, the presentation time of the additional cell would be about 1 to 10 s, preferably about 3 to 8 s. Due to the additional cell, the DVD player or a similar player will indicate a longer total playback time for the DVD. However, the actual time for presenting the DVD is not altered because the additional cell will not be presented.

In the next step, some or all sectors of the additional cell are made defect. Defect means that the sectors cannot be read, in particular neither by a DVD player nor by a home computer, personal computer or the like. In addition, the defect sec¬ tors can not be corrected due to error correction or the like.

The defect sectors are not relevant for a DVD player, because the DVD player does not present the additional cell. However, a usual home computer, personal computer or the like can not read the video file because, then, the video file is handled as a data file including the additional cell with defect sectors, i.e. with errors, resulting in that this file cannot be read and, thus, cannot be copied.

Therefore, the additional cell with its defect sectors forms a copy protection block. -

If desired, more than one copy protection block can be inserted, preferably at the beginnings of video files or the like, e.g. at the beginning of some or each video object or video object set of the DVD.

As an alternative, the copy protection block could also be formed by an addi¬ tional VOBU with defect sectors instead of the additional cell.

In thje following, it. will be described how the defect sensors are preferably gQn- /, ,erated. -

The. channel data described above: are processedLinto animage file Ota graphical _r _ metafile, in particular in RAW -format- This graphical metafile or image^: file-is _^ normally directly used, to -produce a pattern, in particular a glass master or the like, for pressing the DVDs.

In the present invention, this graphical metafile or image file is modified before producing the pattern, in particular the glass master. Namely, the correct graphi¬ cal metafile or image file already containing the additional cell with correct sec- tors is modified such that the some or all sectors of the additional cell are made defect. This can be accomplished in that the desired sectors are identified by means of directories, pointers and the like in the file and, after identification of the desired sectors, these sectors are made defect preferably by changing its sec¬ tor control data as defined above. In particular, at least one or all bytes of the control data, preferably the EDC data, are modified, in particular set "zero" or "one". Due to this modification, the sectors cannot be read or corrected. The modified graphical metafile or image file is then used to produce the pattern, in particular the glass master or the like.

The defect sector results in that the video file with the defect sectors cannot be read as a data file and, therefore, cannot be read by usual home computers, per¬ sonal computers or the like from the DVD as a data file. Therefore, the defect sectors form a very effective means to prevent copying of the DVD by a home computer, personal computer or the like.

In particular, it seems to be sufficient to protect only the first video file in the above sense, i. e. the first file with the beginning or main part of the main content of the DVD, against copying by providing the copy protection block a described above.

Fig. 5 shows very schematically in a presentation not to scale a data carrier 1 , namely a DVD, according to the present invention with a track 2 containing multiple sectors S. These sectors S are organized as described above. At least some or all sectors S of the additional cell are made defect, i.e. cannot be read, as- described above. However,4he copy-protection according to the present inven¬ tion as -described above does not negatively influence playback of the.DVD in a DVD player 3 _or the like.

According to a preferred embodiment, additional defect sectors S are added at - the end of the video file with the additional cell or at the end of the VOBS con¬ taining the video file with the additional cell or at the end of the last cell of any VOB. In particular, a multiplicity of defect sectors is added, preferably more than 10.000, most preferably more than 25.000, even about 40.000 or more de¬ fect sectors. This addition of defect sectors forms a second measure for copy- protection. The addition of further defect sectors makes it even more difficult to copy such a DVD.

The present invention relates in particular to a DVD, preferably to a DVD in the DVD-video format as described above. However, the present invention can be applied in a similar manner also to other optical data carriers or to data carriers in general.

Claims

Claims:

1. Data carrier (1), in particular an optical data carrier, preferably a DVD, comprising one video file or multiple video files each file consisting of a plural- ity of logical sectors (S) stored on the data carrier (1), characterized in that the first video file contains at its beginning a copy protection block with de- feet sectors (S), so that the video file except the copy protection block is read¬ able, in particular by a DVD player (3), but cannot be copied as one data file.

2. Data carrier according to claim 1, characterized in that the video file(s) and sectors (S) at least basically comply with the DVD-video format.

3. Data carrier according to claim 1 or 2, characterized in that each sector (S) contains 2064 bytes with 2048 bytes user data.

4. Data carrier according to any one of the preceding claims, characterized in that the defect sectors (S) are modified non-defect Sectors (S) and/or contain modified sector control data, hi particular that one or all control data, preferably EDC data, are set "O'^!. -

5. Data carrier according to any one of the preceding. claims,^"characterized in that the first video file is a video obj ect or video obj ect set.

6. Data carrier according to claim 5, characterized in that the copy protection block is an additional cell or the first cell of the video object or video object set.

7. Data carrier according to any one of the preceding claims, characterized in that the copy protection block contains 50 to 5.000 sectors (S), preferably 500 to 2.000 sectors (S).

8. Data carrier according to any one of the preceding claims, characterized in that the data carrier (1) contains navigation or pointer information, like a pro¬ gram control block, so that the copy protection block does not form part of the first video file that is displayed by a DVD player (3).

9. Data carrier according to any one of the preceding claims, characterized in that the copy protection block forms a black screen according to DVD standard.

10. Data carrier according to any one of the preceding claims, characterized in that additional defect sectors (S) are additionally stored at the end of the first video file or at the end of a video object or video object set containing the first video file.

11. Data carrier according to claim 10, characterized in that at least 10.000, preferably more than 25.000, additional defect sectors (S) are additionally stored.

12. Method for producing a copy-protected data carrier (1) in the DVD video format, characterized in that an additional cell is inserted at the beginning of a video object forming a first video file, the cell containing multiple sectors (S), and that some or all sec- tors (S) of the additional cell are made defect for forming a copy protection block, so that the video object can not be copied as one data file.

13. Method according to claim 12, characterized in that the presentation or navi¬ gation information pn the data carrier (1), in particular a program control.block, is modified such that the additional cell forming the copy protection block^" is not presented by a DVD player (3). .

14. Method according to claim 12 or 13, characterized in that the additional cell is inserted during the generation of the physical data structure of the data carrier (1), in particular of at least one video object set containing at least one video ob¬ ject.

15. Method according to any one of the claims 12 to 14, characterized in that the additional cell is inserted before generating the data in the writable media format, in particular before generating an image file for producing a master for pressing DVDs.

16. Method according to claim 15, characterized in that some or all sectors (S) of the additional cell are made defect after generating the data in the writable media format, in particular by modifying the image file.

17. Method according to any one of the claims 12 to 16, characterized in that the sectors (S) are made defect by modification of control data.

18. Method according to any one of claims 12 to 17, characterized in that addi¬ tional defect sectors (S) are additionally stored at the end of the video object or video object set containing the first video file.