Method to enable preview in DRM System
Original Publication Date: 2004-Apr-14
Included in the Prior Art Database: 2004-Apr-14
In general, a DRM (Digital Rights Management) system protects the copyrights of contents. It allows the distribution of digital contents in an encrypted form. The protected content can only be rendered by some special players/viewers. Since the content are encrypted, users cannot view the protected content before purchasing it. Promoters usually issue a separate preview rights object for customers to enjoy in limited time or counts (or make a separate preview version of the content). However, some contents may have lost their value after being viewed even only once. Moreover, additional rights object or content version will increase the cost of data management and delivery. Our invention provides a novel method to enable the preview feature in DRM systems, so that the customers could try a low-quality version of the multimedia content before purchasing it. In our invention, the protected content would not be encrypted; instead, we would embed a visible and reversible watermark to the content. Since the watermark is visible, it would reduce the quality of the content, so the user could only view a low-quality version before buying it. If the customer buys the content, a set of rights and a key would be sent to the customer. With the key, the visible watermark could be removed and the customer could then view the original high-quality content. Our invention can protect the content value during preview, and as well save the cost of additional preview rights object or preview version of the delivered content. Thus it facilitates the protected content to be forwarded from one user to another, which is usually encouraged by content/service providers. Furthermore, it can be well applied into the traditional encryption-based DRM system without explicitly infrastructure changing.