Methods for reading watermarks in unknown data types, and DVD drives with such functionality
To prevent playback of pirated, non-encrypted video, a DVD-based system examines data read from a DVD disk for MPEG-like characteristics. If such attributes are detected, the data is examined for the presence of a video usage-control watermark. The presence of such watermark indicates that the video should be distributed only in encrypted form, so playback of video from the disk is prevented.
1. A non-transitory computer-readable medium having instructions stored thereon that, if executed by a computing device, cause the computing device to perform operations comprising:
reading data from a storage medium wherein a type of the data is unknown;
examining the data for a first attribute associated with a media type, wherein the media type is one of a plurality of standard media types;
determining the media type of the data based on the first attribute; and
determining whether a watermark is present if the media type of the data is a recognized media type.
2. The non-transitory computer-readable medium of claim 1 , wherein the operations further comprise preventing playback of the data through an MPEG decoder if the watermark is present.
3. The non-transitory computer-readable medium of claim 1 , wherein the operations further comprise enabling an operation connected to the data if the watermark is present.
4. The non-transitory computer-readable medium of claim 1 , wherein the data is protected with an encryption system, wherein the watermark is associated with the encryption system, and wherein the operations further comprise enabling playback only if the watermark is present and matches the encryption system.
5. The non-transitory computer-readable medium of claim 1 , wherein the first attribute comprises a probability, and wherein the first attribute is detected if the probability is above a first threshold.
6. The non-transitory computer-readable medium of claim 5 , wherein the operations further comprise:
reading additional data from the storage medium if the probability is above a second threshold but below the first threshold;
examining the additional data for the first attribute associated with the media object;
determining whether the watermark is present only if the first attribute is detected from the data and the additional data.
7. The non-transitory computer-readable medium of claim 1 , wherein the operations further comprise:
examining the data for a second attribute also associated with the media object if the first attribute is detected; and
determining whether the watermark is present only if the second attribute is also detected.
8. The non-transitory computer-readable medium of claim 1 , wherein the first attribute comprises a presence of apparent macroblocks.
9. The non-transitory computer-readable medium of claim 1 , wherein determining whether the watermark is present comprises performing a watermark-read operation.
10. The non-transitory computer-readable medium of claim 9 , further comprising synchronizing the watermark-read operation in accordance with a characteristic of the data.
11. The non-transitory computer-readable medium of claim 10 , wherein the characteristic is an apparent start of a macroblock.
12. The non-transitory computer-readable medium of claim 1 , wherein the first attribute comprises an MPEG class signature in spectral or statistical data corresponding to the data.
13. The non-transitory computer-readable medium of claim 1 , wherein the first attribute comprises a JPEG header.
14. A method comprising:
reading data, at a processor, from a storage medium, wherein a type of the data is unknown;
examining the data, at the processor, for a first attribute associated with a media type, wherein the media type is one of a plurality of standard media types;
determining the media type of the data based on the first attribute; and
determining, at the processor, whether a watermark is present if the media type of the data is a recognized media type.
15. The method of claim 14 , further comprising preventing playback of the data through an MPEG decoder if the watermark is present.
16. The method of claim 14 , further comprising enabling an operation connected to the data if the watermark is present.
17. The method of claim 14 , wherein the data is protected with an encryption system, wherein the watermark is associated with the encryption system, and wherein the operations further comprise enabling playback only if the watermark is present and matches the encryption system.
18. A device comprising:
a processor;
a storage medium reader operatively coupled to the processor configured to read data from a storage medium wherein a type of the data is unknown;
a question module operatively coupled to the processor configured to examine the data for a first attributed associated with a media type, wherein the media type is one of a plurality of standard media types;
a second question module operatively coupled to the processor configured to determine the media type of the data based on the first attribute; and
a watermark reader operatively coupled to the processor and configured to determine whether a watermark is present if the media type of the data is a recognized media type.
19. The device of claim 18 , wherein the processor is configured to prevent playback of the data through an MPEG decoder if the watermark is present.
20. The device of claim 18 , wherein the processor is configured to enable an operation connected to the data if the watermark is present.