Method and apparatus for processing a stream that contains encrypted information
First Claim
1. A method of processing information that encodes a video stream (20) of image frames, the video stream comprising mutually interspersed first and second subsets of the image frames, the method comprising encrypting the information for the image frames of the first subset;
- producing a stream that contains, interspersed with one another, the information for the first subset in encrypted form and the information for the image frames (22, 24) of the second subset at least partly in plain form.
1 Assignment
0 Petitions
Accused Products
Abstract
Video information is transmitted encrypted as part of a video stream, so as to provide conditional access to the video information. The video stream comprising mutually interspersed first and second subsets of the image frames. The information for the image frames of the first subset is encrypted. A stream is broadcast (10) that contains, interspersed with one another, the information for the first subset in encrypted form and the information for the image frames of the second subset at least partly in plain form. This permits receivers (12) to detect the unencrypted parts without decryption and to generate and store pointer information (124) to the unencrypted parts. The pointer information can be used later for the purpose of trick play (126) at the receiver.
-
Citations
9 Claims
-
1. A method of processing information that encodes a video stream (20) of image frames, the video stream comprising mutually interspersed first and second subsets of the image frames, the method comprising
encrypting the information for the image frames of the first subset; producing a stream that contains, interspersed with one another, the information for the first subset in encrypted form and the information for the image frames (22, 24) of the second subset at least partly in plain form. - View Dependent Claims (2, 3, 4, 5, 6, 9)
-
7. A reception and replay apparatus (12) for receiving a stream that contains packets with information that encodes a stream of image frames partly in encrypted form, the apparatus comprising
a reception unit (120) for receiving the packets; -
storage unit (122) for storing packets received by the reception unit;
a detection unit (124) for detecting for each particular packet whether packet is in unencrypted form and storing a pointer to the particular packet conditional on detection that the particular packet is in unencrypted form;
a retrieval unit (126) for controlling selective retrieval of the particular packet from the storage unit under control of the pointer. - View Dependent Claims (8)
-
Specification