HK1088110B - Read-only recording medium containing sample data and reproducing method thereof - Google Patents
Read-only recording medium containing sample data and reproducing method thereof Download PDFInfo
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- HK1088110B HK1088110B HK06108167.4A HK06108167A HK1088110B HK 1088110 B HK1088110 B HK 1088110B HK 06108167 A HK06108167 A HK 06108167A HK 1088110 B HK1088110 B HK 1088110B
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Description
Technical Field
The present invention relates to a read-only recording medium containing encrypted source data and sample data thereof.
The invention also relates to a method of reproducing said recording medium.
Background
In the past, it has been desired to widely use an online multimedia content selling method. In the online sales method, moving picture data or audio data is provided to a recording medium, such as a writable CD or DVD, of a user through a data network and then played from the recording medium.
Audio data provided through a network is called EMD (electronic music distribution) audio data. EMD audio data is provided by many content providers. However, the content provider encodes EMD audio data in mutually different formats and adds a different and unique copy protection key, i.e., an EMD audio data encryption key, to prevent unauthorized copying and protect its own copyright.
Before playing the downloaded EMD audio data, a decryption key appropriate for the downloaded EMD audio data must be obtained from the content provider that provided the EMD audio data. The decryption key is used to decrypt EMD audio data encrypted with the corresponding copy protection key.
Since it is almost impossible to obtain an appropriate decryption key without a legal license, EMD audio data can be protected against illegal copying, and thus its copyright is also protected.
To enjoy the benefits of such data protection, high-quality moving image data and/or audio data will typically be encrypted and sold to users over a network. In addition, due to the advantages of data protection, the distribution of the online content selling method is expected to be more and more.
However, as described above, playing encrypted EMD audio data must use a copy protection key, i.e., a decryption key. Therefore, the user cannot play any part of the EMD audio data downloaded on the writable recording medium with the optical disc device until he or she purchases the decryption key. In other words, it is not possible for the user to confirm at all whether the downloaded EMD audio data is what he or she needs, or whether its audio quality is better or lower than what he or she desires. Thus, the user may be reluctant to purchase a playback license key, i.e., a decryption key for the downloaded EMD audio data.
Meanwhile, when a user wants to purchase his or her favorite digital song or tune, he or she finds a website on the internet and then finds a website containing his or her favorite song or tune. If found, he or she requests to download them onto the recording medium. These processes require much time and effort, which would prevent the spread of the online sales method of digital content.
Disclosure of Invention
An object of the present invention is to provide a read-only recording medium on which encrypted moving image data and/or audio data and unencrypted sample data are recorded.
It is another object of the present invention to provide a method of reproducing only unencrypted sample data of a read-only recording medium without a decryption key, which will prompt a user to purchase the decryption key on-line.
The read-only recording medium storing data according to the present invention is characterized in that it comprises: a first area for storing data; and a second area for storing management information of the data stored in the first area, wherein the first area contains encrypted source data and unencrypted sample data having the same content as part of the source data, and the second area contains location information of the unencrypted sample data.
A method of reproducing a recording medium containing encrypted source data and unencrypted sample data having the same content as the partially encrypted source data according to the present invention is characterized by comprising the steps of: when the encrypted source data is requested to be played, checking whether the optical disc device has decryption information of the encrypted source data; if the decryption information does not exist, reading the position information pointing to the non-encrypted sample data; the non-encrypted sample data is reproduced using the read position information without reproducing the encrypted source data requested to be played.
Another method of reproducing a recording medium containing encrypted source data and unencrypted sample data having the same content as the partially encrypted source data according to the present invention is characterized by comprising the steps of: when the encrypted source data is requested to be played, checking whether the optical disc device has decryption information of the encrypted source data; if there is no decryption information, receiving the decryption information by communicating with an external device and storing it on the optical disc device; when the encrypted source data is decrypted by using the stored decryption information, the encrypted source data is reproduced based on the position information of the encrypted source data.
According to an aspect of the present invention, there is provided a method of reproducing data from a recording medium containing encrypted source data and sample data that is identical to a part of the source data and is not encrypted, comprising the steps of: (a) checking whether a decryption key required for decrypting the encrypted source data exists; (b) if the decryption key does not exist, requesting the decryption key from a website according to uniform resource locator information and optical disc identification information, wherein the uniform resource locator information indicates a location of the website providing an expected decryption key of the encrypted source data; and (c) regenerating the encrypted source data using the decryption key.
According to another aspect of the present invention, there is provided an apparatus for reproducing data from a recording medium containing encrypted source data and sample data identical to a portion of the source data and not encrypted, comprising: a controller which checks whether a decryption key required to decrypt the encrypted source data exists, and if the decryption key does not exist, requests the decryption key from a website based on uniform resource locator information and disc identification information, wherein the uniform resource locator information indicates a location of the website which provides an expected decryption key of the encrypted source data; and a reproducing unit that reproduces the encrypted source data based on control of the controller.
In view of the above, the present invention is characterized by enabling a user to confirm whether source data written on a read-only reproduction medium is what he or she needs without purchasing a decryption key for the source data. Therefore, preview or trial listening of the sample data naturally results in purchasing the decryption key of the encrypted content. In addition, the online sales process is very simple and fast, since the sales can be done by just downloading the decryption key.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. Together with the description, the drawings serve to explain the principles of the invention. Wherein:
fig. 1 is a simplified block diagram showing an optical disc apparatus for implementing the data reproducing method of the present invention;
fig. 2 schematically shows a relationship between a PGCI (program chain information) recorded on a read-only optical disc according to the present invention and a sample AOB (audio object) of a source audio track;
fig. 3 schematically shows a relationship between a PGCI recorded on a read-only optical disc according to the present invention and a source track containing encrypted audio data;
fig. 4 schematically shows the relationship between CI (unit information) recorded on a read-only optical disc according to the present invention and an encrypted source and an unencrypted sample video object;
FIGS. 5a and 5b are flow diagrams illustrating embodiments of methods of selectively playing encrypted data or unencrypted sample data in accordance with the present invention;
fig. 6 is an example of a screen, and a playback error window pops up because there is no decryption key.
Detailed Description
In order that the present invention may be fully understood, preferred embodiments of the present invention will be described hereinafter with reference to the accompanying drawings.
Fig. 1 is a simplified block diagram showing an optical disc apparatus incorporating the data reproducing method of the present invention. The apparatus may be an optical disc drive installed in a Personal Computer (PC) capable of connecting to the internet.
The optical disc apparatus in fig. 1 includes an optical pickup 2 for reading a signal written on a read-only optical disc 1 such as a DVD-ROM; a reproduction processor 3 for processing the read signal to restore original data; a buffer 5 for buffering temporary data such as encrypted data generated in a reproduction operation; a memory 7 for storing navigation data and a decryption key of the recorded source data, wherein the navigation data is management information for reproduction control of the recorded data; the system controller 4, for all elements controlled in playback, selectively plays back encrypted source data or unencrypted sample data, and requests/receives a decryption key when connected to a computer.
The read-only optical disc 1 contains not only encrypted source data, i.e. video and/or audio content, but also unencrypted sample data that is part of the same source data.
The read-only optical disc 1 may be a DVD-ROM having two areas, one for source data and sample data and the other for their management information. If the source data consists of multiple audio tracks, each audio track is written with sample audio data. In addition, sample audio data associated with the audio track forms a sample track.
The track is managed as AOBs (audio objects), so a CI (unit information, i.e., reproduction control information) is generated for each AOB in the management information area. The CI includes location information (i.e., start address and end address, or start address and duration) of the associated AOB.
Thus, if the data area has N source audio tracks, the optical disc includes 2 × N AOBs and 2 × N CIs.
The management information area of the read-only optical disc 1 includes an original and user-defined PGCI (program chain information) including the created CI as its own field element. Thus, the PGCI is able to index multiple AOBs individually as indicated by the various CI fields it contains. That is, if a PGCI is selected automatically or by the user, the AOB indicated by the CI in the selected PGCI can be found and played.
Fig. 2 schematically shows the relationship between PGCI recorded on a read-only optical disc and sample AOB of the source audio track. In the example of fig. 2, the source track "AOBN +1, N +2, N +3, … …" containing encrypted audio data has been recorded on the read-only optical disc 1, and the sample track "AOB 1, 2, 3, … …" has also been recorded thereon. Each sample track has the same unencrypted audio data as a portion of each source track "S1, S2, S3, … …". In addition, a plurality of CI "cells 1, 2, 3, … …" of the sample track "AOB 1, 2, 3, … …", which include respective position information (start address "DA _ S _ P" and end address "DA _ E _ P" or start address "DA _ S _ P" and duration "DA _ Dur") have been written in the original PGCI. Thus, if the original PGCI is selected, only the sample track "AOB 1, 2, 3, … …" of the source track "AOB N +1, N +2, N + 3" is played.
Fig. 3 schematically shows the relationship between the PGCI recorded on the read-only optical disc 1 and the source track containing the encrypted audio data. In the example of fig. 3, a plurality of CI "units N +1, N +2, N +3, … …" containing respective position information (start address "UA _ S _ P" and end address "UA _ E _ P" or start address "UA _ S _ P" and duration "UA _ Dur") have been written in a user-defined PGCI. Thus, if the user-defined PGCI is selected, and if there is a decryption key for the source track, the source track "AOB N +1, N +2, N +3, … …" is played continuously.
Thus, if the decryption key is not present, the system controller 4 selects the original PGCI and then plays the non-encrypted sample data specified by the CI contained in the original PGCI, and if the decryption key is present, the system controller 4 selects the user-defined PGCI and then plays the source track when the encrypted data is decrypted using the unique decryption key stored in the memory 6.
If video contents, not audio contents, are recorded on the data area of the read-only optical disc 1, each source track is applied to VOBs (video objects) instead of AOBs (audio objects). However, the management information of the VOB is the same as the management information of the AOB. That is, as shown in fig. 4, the sample VOB "VOB 1" is generated as the source VOB "VOB 2". The sample VOB "VOB 1" contains unencrypted video data which is identical to the portion of the source VOB "VOB 2" containing encrypted video data. In addition, two CIs relating to the sample and source VOBs, respectively, are written in different or the same PGCI.
An embodiment of a method of reproducing the read-only optical disc 1 containing the data configured as above is explained in detail below.
Fig. 5a and 5b are flow charts showing embodiments of the present invention.
When the read-only optical disc 1 is loaded into the optical disc device of fig. 1 (S10), the system controller 4 reads the above-mentioned management information, i.e., the original and user-defined PGCI, CI, etc., written in the management information area of the read-only optical disc 1, and writes them to the memory 6 (S11).
Then, if necessary, the system controller 4 will execute the appropriate playback program written in advance in the read-only optical disc 1 (S13), and check whether a decryption key for decrypting the encrypted source data written in the read-only optical disc 1 exists in the memory 6 (S13). The following process and decryption key check process will be performed by the playback program executed instead of the system controller 4.
If there is no decryption key, the system controller 4 generates a playback error message and transmits it to the connected PC (S14). The playback error message includes an explanation of the purchase of the decryption key and the reason why there is no decryption key for the source data.
Fig. 6 is an example of a screen in which such a playback error message is output. The playback error message shown in fig. 6 includes an inquiry window inquiring whether the user purchases a decryption key. Exemplary interrogation windows also include: a URL (uniform resource locator) that gives the web address of the web site on the internet that provides the decryption key and a download button that enables the user to purchase the decryption key associated with the source data by downloading.
If the user does not request the online purchase of the decryption key (S15), the system controller 4 automatically selects and checks the original PGCI including a plurality of CI "units 1, 2, 3, … …" associated with the sample data stored in the memory 6 (S16). Then, the system controller 4 knows the position of each sample AOB in the read-only optical disc 1 from the pair of fields "DA _ S _ P" "DA _ E _ P" of each CI (S17).
Thereafter, the system controller 4 searches the read-only optical disc 1 by moving the optical pickup 2 inward and outward, looking for the sample AOB indicated by each pair of fields "DA _ S _ P" and "DA _ E _ P", and continuously reproduces only the sample AOB without performing a decryption operation (S18).
Then, after the user audits or tries the audio songs or movies of the respective sections on the optical disc 1, it can be decided whether to purchase the decryption key of the source data written on the read-only optical disc 1 without purchasing a unique decryption key.
If the decryption key is present (S13), the system controller 4 checks the user-defined pggi stored in the memory 6 and including a plurality of CI "cells N +1, N +2, N +3, … …" associated with the source AOB (S20). Then, the system controller 4 knows the location of each source AOB on the read-only optical disc 1 based on a pair of fields "UA _ S _ P" and "UA _ E _ P" for each CI in the user-defined PGCT (S21).
After that, the system controller 4 reads out the decryption key for the source AOBs "AOBs N +1, N +2, N +3 … …" from the memory 4, and searches the read-only optical disc 1 by moving the optical pickup 2 inward and outward, looking for each source AOB indicated by each pair of fields "UA _ S _ P" and "UA _ E _ P". When the target source AOB is found, the system controller 4 performs a regenerating operation of the AOB when decrypting the encrypted source data contained in the AOB with the read decryption key (S22).
If the user requests an online purchase of the decryption key with the playback error window displayed (S15), the system controller 4 reads URL (uniform resource locator) information and disc identification information, such as a 2-byte serial number assigned to the read-only optical disc 1, of a website that provides the intended decryption key of the source data from the management area or the memory 6 of the read-only optical disc 1. The read address and disc identification are transmitted to the connected PC (S30).
The purchase process described above is initiated by the user clicking on the "download" button of the exemplary Play error window in FIG. 6.
The website addressed by the stored URL identifies which decryption key is required based on the received disc identification. I.e. it searches a database therein for a decryption key associated with the received disc identification or serial number. If found, the website downloads the found decryption key to the PC. The PC passes the downloaded decryption key to the system controller 4 of the optical disc drive connected to the PC (S31). The decryption key delivery may be according to a predetermined protocol between the website and a PC connected to the website.
When the optical disc 1 is loaded into the optical disc drive, the URL and disc identification that have been recorded in the management information area of the read-only optical disc 1 are restored in the memory 6 together with management information such as PGCI and CI.
The system controller 4 stores the received decryption key associated with the disc identification in the memory 6 (S32).
Thereafter, when decrypting the encrypted source data with the decryption key stored in the memory 6, the system controller 4 continuously regenerates all the source AOBs indicated by each of the user-defined PGCIs, the steps being the same as described above.
In addition, the user-defined PGCI may not be written in the management information area of the read-only optical disc 1 but be provided by a website so that, when purchase of a decryption key is requested with the disc id, the requested decryption key is downloaded. The provided user-defined PGCI matching the source data of the read-only optical disc 1 is stored in the memory 6 and then referred to by the system controller 4 when playing the source AOB.
The above method is applicable to various read-only optical discs such as CDs (compact discs) and VCDs (video discs) in addition to DVD-ROMs. In addition, the method can be applied to moving image data and still image data in addition to audio data.
It will be apparent to those skilled in the art that the present invention is susceptible to many alternatives, modifications, and variations. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.
Claims (14)
1. A method of reproducing data from a recording medium containing encrypted source data and sample data that is identical to a portion of the source data and is not encrypted, comprising the steps of:
(a) checking whether a decryption key required for decrypting the encrypted source data exists;
(b) if the decryption key does not exist, requesting the decryption key from a website according to uniform resource locator information and optical disc identification information, wherein the uniform resource locator information indicates a location of the website providing an expected decryption key of the encrypted source data; and
(c) and regenerating the encrypted source data by using the decryption key.
2. The method of claim 1, wherein said step (b) comprises the step of downloading said decryption key from said website.
3. The method according to claim 2, wherein said downloading step downloads said decryption key associated with said disc identification information.
4. The method of claim 2, wherein the downloading step downloads the decryption key after paying for the decryption key.
5. The method of claim 1, wherein the encrypted source data comprises a plurality of digital audio or video, and wherein step (b) requests the decryption key from the website to decrypt the plurality of digital audio or video.
6. The method of claim 1, wherein the sample data is reproducible without using the decryption key.
7. The method of claim 1, wherein step (b) further comprises:
(b1) if the decryption key does not exist, indicating the position of the website for obtaining the decryption key; and
(b2) connecting with the website to obtain the decryption key based on the indicated location.
8. An apparatus for reproducing data from a recording medium containing encrypted source data and sample data that is identical to a portion of the source data and is not encrypted, comprising:
a controller which checks whether a decryption key required to decrypt the encrypted source data exists, and if the decryption key does not exist, requests the decryption key from a website based on uniform resource locator information and disc identification information, wherein the uniform resource locator information indicates a location of the website which provides an expected decryption key of the encrypted source data; and
a reproducing unit that reproduces the encrypted source data based on control of the controller.
9. The apparatus of claim 8, wherein the controller further transmits the disc identification information to a website indicated by the uniform resource locator information to request the decryption key.
10. The apparatus of claim 8, further comprising:
a memory for storing a decryption key of the request received from the website.
11. The apparatus of claim 10, wherein the controller controls the memory to store the requested decryption key.
12. The apparatus of claim 10, wherein the controller further controls the memory to store the requested decryption key after paying for the decryption key.
13. The apparatus of claim 8, wherein the encrypted source data comprises a plurality of digital audio or video, wherein the controller requests the decryption key from the website to decrypt at least one digital audio or video.
14. The apparatus of claim 8, wherein the sample data is reproducible without using the decryption key.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR2001/12998 | 2001-03-13 | ||
KR1020010012998A KR20020072934A (en) | 2001-03-13 | 2001-03-13 | Read only optical disc recorded demo data, and method for reproducing them |
Publications (2)
Publication Number | Publication Date |
---|---|
HK1088110A1 HK1088110A1 (en) | 2006-10-27 |
HK1088110B true HK1088110B (en) | 2010-09-03 |
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