The US Patent Office issues new patents on Tuesdays. Issued patents and published applications may be early indicators of the kinds of issues being addressed by inventors and/or the companies for whom they work. Assigned to Macrovision, the first patent describes techniques for the dynamic protection of optical media. Assigned to Microsoft, the second patent describes audio watermarking with dual watermarks.
6,952,479, "Dynamic copy protection of optical media," assigned to Macrovision.
Abstract
A method for copy protection includes receiving data in a recording module representing content to be recorded on a recording medium, the data including an indication that the content is to be protected from unauthorized copying. Responsive to the indication, the recording module signals a protection module to initiate a protection protocol in synchronization with the recording module. The protection module generates control information, so as to prevent the unauthorized copying of the content that is to be protected, and conveys the control information to the recording module, in accordance with the protocol. The recording module combines the control information with the data representing the content in the recording module, for recording on the recording medium.
6,952,774, "Audio watermarking with dual watermarks," assigned to Microsoft.
Abstract
A watermark encoding system encodes an audio signal with both a strong and a weak watermark. The strong watermark identifies the content producer and is designed to survive all typical kinds of processing and malicious attacks. The weak watermark identifies the content as an original and is designed to be significantly removed as a result of most normal signal processing (other than A/D and D/A). The watermark encoding system has a converter to convert an audio signal into frequency and phase components and a mask processor to determine a hearing threshold for corresponding frequency components. The watermark encoding system also has a pattern generator to generate both the strong and weak watermarks and a watermark insertion unit to selectively insert either the strong or weak watermark into the audio signal. The watermark insertion unit adds the strong watermark to the audio signal when the signal exceeds the hearing threshold by a buffer value (e.g., 1-8 dB) and adds the weak watermark insertion unit when the signal falls below the hearing threshold by the buffer value. When the signal falls within the buffer area about the hearing threshold, the insertion unit takes no action. A watermark detecting system is equipped with a watermark detector that determines which block interval of the watermarked audio signal contains a watermark pattern and if the strong or weak watermark is present in that block interval of the signal.