Abstract: A device (3400) for processing an encrypted data stream (3401), wherein the device (3400) comprises a decrypting unit (3402) for generating a decrypted data stream (3403) from the encrypted data stream (3401), a detecting unit (3404) for detecting position information of at least one intra-coded frame in the decrypted data stream (3403), and a replacement unit (3405) for replacing, based on the detected position information, portions of the encrypted data stream (3401) by corresponding portions of the decrypted data stream (3403).

Abstract: A device (3200) for processing an encrypted data stream (3201) in a cryptographic system, in which decryption data (3204) are provided for decrypting each segment (3202) of the encrypted data stream (3201) for reproduction of the decrypted data stream, wherein the device (3200) comprises a first determining unit (3209) for determining, in case of switching from a first reproduction mode (1501) of reproducing the data stream (3201) to a second reproduction mode (1502) of reproducing the data stream (3201), a current position of reproduction within the data stream, and a second determining unit (3210) for determining a starting position for starting reproduction in the second reproduction mode (1502) based on the determined current position.

Abstract: A device (3000) for processing an encrypted data stream (3001), wherein decryption messages are provided for decrypting each segment (1403) of the encrypted data stream (3001), wherein each decryption message comprises a number of decryption elements, wherein the device (3000) comprises a detection unit (3002) for detecting the number of decryption elements per decryption message, and a determining unit (3003) for determining a position for providing the decryption messages in relation to the sequence of the segments (1403), based on the detected number.

Abstract: A trick play signal is derived from a stored, and typically encrypted video stream. The video stream comprises data representing a series of I frames and P or B frames encoded at a variable bit rate, the I-frames being decodable independent of any other frame, decoding of the P or B frames requiring reference to other frames. Selected segments of data are retrieved from the video stream. Each segment corresponds to a part of data from the stream with a selected length. Distances between successive retrieved segments are selected dependent on a trick play speed. A trick play video signal is generated that comprises an earliest first frame from each respective segment. Stream specific properties of the stream are determined that are indicative of a rate at which the I-frames occur in the stream.

Abstract: A video stream and different trickplay versions of that stream are stored as separate files in a randomly accessible storage medium. In order to facilitate seamless switching between streams linking information is provided, which links positions of content within the normal play stream to positions of corresponding content within the trickplay streams. Upon receiving a switch command for switching between trickplay modes or to or from a normal play mode the linking information is consulted to determine corresponding locations in different streams for the different modes and used to jump to a point within the new stream.

Abstract: For conditional access purposes a stream is used in which at least two different decryption algorithms are needed for decryption of packets that encode different interspersed parts of the same signal for (quasi-)continuous rendering (such as an audio or video signal). Information is included in the stream to indicate dynamically which decryption algorithm should be used for which packets. In this way, it is possible for example to use a more robust algorithm with a less frequently changing key and a less robust algorithm with a more frequently changing key, interspersed with one another for the same signal. Also, different algorithms may be used for transcrypted and not transcrypted-packets of the same signal for example when an alternative is needed for the original encryption algorithm that was used for the non-transcrypted packets.

Abstract: A method and apparatus (100) for handling a layered digital video stream, comprising a base layer stream and an enhancement layer stream for providing HDTV, is disclosed. Either of the base layer stream or the enhancement layer stream is stored on a hard disc (101), and the other is stored on an optical disc by means of an optical disc drive (102). The streams are handled separately until they are utilized for providing HDTV. When the layered video stream is to be played back with HDTV quality, the base layer stream and the enhancement layer stream are synchronized by means of a synchronizer (106) for referring to the same frame. The synchronized streams are then decoded by means of a base decoder (105a) and an enhancement decoder (105b), which outputs decoded streams that are combined by an adder 112.

Abstract: A storage device 500 includes an input 405 for receiving a digital video stream complying with a predetermined video encoding standard via a digital video communication system. The stream includes a sequence of digital video frames, a sequence of program clock reference stamps (PCR) and a sequence of video presentation time stamps (PTS). A time-base modifier 510 replaces the PTS's by respective modified video presentation time stamps (M-PTS) based on a constant predetermined frame time between successive presentation time stamps and replaces the PCR's by respective modified program clock reference stamps (M-PCR) by scaling the PCR's using a scaling factor that depends on a ratio of an expected time between a video presentation time stamp j and a preceding video presentation time stamp j?n and an actual time between the video presentation time stamp j and the preceding video presentation time stamp j?n, where j?n>0. The expected time is n times the predetermined frame time.

Abstract: A stream of video data is normally played in forward direction. Units of control word information required to decrypt successive segments of the stream are supplied synchronized to the stream. During reverse mode replay sections of the stream are replayed in reverse order. The units of control word information are resynchronized relative to supply of video information. Crossing of boundaries between segments during reverse mode replay triggers supply of selected units. The units are selected so that they contain the control word needed to decrypt a first segment that is normally previous to a second segment that ends at the boundary. Generally, this is a unit that normally starts to be supplied just before or after the start of the first segment.

Abstract: A method and apparatus for providing user controlled implementation of trick play modes of operation of digital video data is disclosed. A user interface is provided on a video screen. The user is prompted to select a speed on the user interface at which the trick play mode will operate. The user is then prompted on the user interface to select how the selected speed is implemented. Alternatively, a list of possible implementations (predefined modes of operation) are displayed on the user interface from which the user can select the desired mode of operation.

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.

Abstract: A signal (24) that contains a stream of encrypted data and a plurality of individually identified streams (20, 22) of messages. Each of the streams (20, 22) of messages contains decryption information for decrypting a common part of the encrypted data. In a receiving and recording apparatus a mode selection unit (16) selects an operating mode from a plurality of modes including a live rendering mode and a replay mode for rendering the signal with a rendering unit (14) when received live and when replayed from storage respectively. A decoder (14) decrypts the encrypted data using a selectable one of the streams of messages. The decoder (14) selects the stream of messages dependent on the selected operating mode.