Abstract: A transmission system includes a transmitter (10) and at least one receiver (14) configured to receive signals transmitted therefrom. Carousel-forming data file and directory objects are sent in cycles, with predetermined groups of file and directory objects being formed into respective modules at the transmitter, suitably according to MPEG-2 DSM-CC protocols. Each of the modules is transmitted as a whole, and the receiver is arranged to record received file data and directory objects under a predetermined grouping formulation, at elementary stream or module level.

Abstract: Various methods are disclosed for producing an edited MPEG audio/video stream from first and second streams recorded in a transport-stream format normally intended for broadcast purposes. According to one implementation, a bridge sequence is generated which recodes data from both of the original streams, in the region of the edit point. Padding packets are inserted in the elementary streams to adjust a continuity counter values so as to allow continuous decoding across the join between bridge sequence and second sequence proper. In another implementation, seamless playback is not required, the bridge sequence is omitted, and various process are implemented “on-the-fly” to generate an edited stream compliant with MPEG-2 specification. To this end, exit and entry points are constrained to certain types of coded pictures, and offset between time-bases is adjusted to avoid buffer overflow.

Abstract: The application relates to a method of and devices for encoding an information stream (20) into a variable bit rate (VBR) encoded information stream (24). The application discloses a method of estimating the relation between the variable bit rate, the recording time and the storage capacity of a record carrier. The deviation of the estimated recording time from the true recording time is kept within predefined limits and it is prevented that deviations from several successive recordings accumulate.

Abstract: Broadcast data received in MPEG Transport Stream format (TS) is processed (8) to produce a modified transport stream for recording on an optical disc (3) to record the content of a selected audio-visual program. Various techniques are disclosed for permitting random access within the recording, but without re-packetizing or remultiplexing the audio and video elementary streams, for example into program stream format. The received TS (DVIN) occasionally includes stream mapping information (PAT/PMT) identifying a transport packet ID code associated with each elementary stream, said stream mapping information being subject to change throughout the received TS. The packet IDs in the modified transport stream can be re-mapped to a uniform set of values to permit random entry to the recorded stream. Alternatively, the current stream mapping information may be inserted at every potential entry point in the modified stream.

Abstract: A method of, and apparatus for, encoding and multiplexing a digital video picture are provided using intra-coded fields only at a relatively high bit-rate, with each picture being encoded as a sequence of slices from the video image field. The encoding suitably complies with MPEG or similar requirements, and the intra-coding is further constrained so that the maximum number of bits for each slice in the picture is limited, and the delivery schedule of the bits to a decoder is more tightly constrained than is implied by the MPEG decoding models. In this way it is possible to build a high quality, low cost MPEG (or similar) encoder and decoder for video communications over digital interconnection standards such as IEEE 1394.

Abstract: A method and apparatus are provided to enable variable speed forwards or reverse play of motion-prediction coded sequences of video signal frames. Successive images of a sequence are MPEG encoded with some images of the sequence becoming I-frames and the remainder P- or B-frames. The frame data is formatted to sequences of fixed size data blocks (I,P,B) to form a data block stream into which further, information blocks (i) are inserted at periodic intervals. Each information block (i) carriers a pointer to the relative location in the data block stream of the first data block of the immediately preceding I-frame.

Abstract: Various methods are disclosed for producing an edited MPEG audio/video stream from first and second streams recorded in a transport-stream format normally intended for broadcast purposes. According to one implementation, a bridge sequence is generated which recodes data from both of the original streams, in the region of the edit point. Padding packets are inserted in the elementary streams to adjust a continuity counter values so as to allow continuous decoding across the join between bridge sequence and second sequence proper. In another implementation, seamless playback is not required, the bridge sequence is omitted, and various process are implemented “on-the-fly” to generate an edited stream compliant with MPEG-2 specification. To this end, exit and entry points are constrained to certain types of coded pictures, and offset between time-bases is adjusted to avoid buffer overflow.

Abstract: In a DSM-CC receiver (12), a signal comprising a periodically repeated plurality of data sections is received. Storage means (14) is provided for caching the data sections included in the signal, and said storage means incorporates a file management mechanism based on file names. Each data section is received (100) under a corresponding file name, and the received file names are modified (140) within the receiver to distinguish between previous or subsequent versions of the same data sections of the signal that are stored in said storage means. Files currently in use are not overwritten, but are marked (135) for later deletion (155). Individual files can be extracted from DSM-CC modules and cache. In this case, individual file names are modified by reference to version information received for the module as a whole.

Abstract: A digital video recorder or similar apparatus implements a method of converting an input data stream having an MPEG-2 Program Stream (PS) format into an output data stream having an MPEG-2 Transport Stream (TS) format. The input data stream (PS) includes data of at least first and second elementary data streams (404, 406) formed and multiplexed in compliance with a PS decoder model. A scheduler (412) within the apparatus inhibits reading of a further data block from the input stream when, in the absence of a vacancy for data of an audio elementary stream within a target decoder model (418), a clock reference (SCR) of said input data stream advances beyond a clock reference of said output data stream by a predetermined waiting threshold.

Abstract: A digital video recorder or similar apparatus implements a method of converting an input data stream having an MPEG-2 Transport Stream (TS) format into an output data stream having an MPEG-2 Program Stream (PS) format. The input data stream (TS) includes data of at least first and second elementary data streams (404, 406) formed and multiplexed in compliance with a TS decoder model. The first elementary stream is a video stream, while the second stream is an audio stream of lower data rate. The input stream is parsed (402) and the elementary streams are demultiplexed into respective FIFO queues 404/406. Each stream is further parsed to obtain and calculate time stamp information which is queued separately at (408/410) with pointers to the stream data (at 404/406). The schedule and packetisation applied to the elementary streams in the input stream (TS) cannot be applied directly in creating the output stream (PS).

Abstract: In a DSM-CC receiver (12), a signal comprising a periodically repeated plurality of data sections is received. Storage means (14) are provided for catching the data sections included in the signal (13) where the act of accessing a data section results in a reference being created, this reference being removed when no longer being accessed. A reference count is kept for each data section such that a data section is marked for deletion if its reference count falls to zero. There is a further aspect where the storage means (14) are defragmented by noting the data sections that are being referenced and then, in any order, compacting these referenced data sections by relocating them together in one part of the storage means (14) and updating the values of pointers that referred to the moved cells.

Abstract: An information stream is encoded into a variable bit rate encoded information stream. The relation is estimated between the variable bit rate, the recording time and the storage capacity of a record carrier. The deviation of the estimated recording time from the true recording time is kept within predefined limits and accumulation of deviations from several successive recordings is prevented.

Abstract: A method and apparatus are provided for generating bridge segments to enable editing jumps to be made from one A/V segment to another while handling timing and frame constraints imposed by the A/V segment compliance with coding conventions, such as MPEG. The bridge segment is constructed by copying data from the two sequences to be bridged, with some demultiplexing, decoding, remultiplexing and re-encoding of this data to maintain the validity of the edited data stream. Different procedures in terms of copying and/or re-encoding are applied in dependence on the picture encoding types at the source and destination of the edit via the bridging segment.

Abstract: Method and apparatus for implementing an extended system of file management on a data storage medium while retaining compatibility with both basic and extended implementations of the file system, the file system providing management information stored on said medium and including at least one management information table containing a number of file information records enabling access to a number of data files stored on said medium. The method comprises distinguishing between basic files, to be accessible in both basic and extended implementations, and extension files, not necessary for a basic implementation, and creating and maintaining said file management table such that records relating to the basic files are stored together in a first part of the table.

Abstract: In a DSM-CC receiver (12), a signal comprising a periodically repeated plurality of data sections is received. Storage means (14) are provided for catching the data sections included in the signal (13) where the act of accessing a data section results in a reference being created, this reference being removed when no longer being accessed. A reference count is kept for each data section such that a data section is marked for deletion if its reference count falls to zero. There is a further aspect where the storage means (14) are defragmented by noting the data sections that are being referenced and then, in any order, compacting these referenced data sections by relocating them together in one part of the storage means (14) and updating the values of pointers that referred to the moved cells.

Abstract: In a DSM-CC receiver (12), a signal comprising a periodically repeated plurality of data sections is received. Storage means (14) is provided for caching the data sections included in the signal, and said storage means incorporates a file management mechanism based on file names. Each data section is received (100) under a corresponding file name, and the received file names are modified (140) within the receiver to distinguish between previous or subsequent versions of the same data sections of the signal that are stored in said storage means. Files currently in use are not overwritten, but are marked (135) for later deletion (155). Individual files can be extracted from DSM-CC modules and cache. In this case, individual file names are modified by reference to version information received for the module as a whole.

Abstract: A transmission system, comprising a transmitter (10) and at least one receiver (14) is configured to receive signals (12) transmitted therefrom. Broadcast data in the transmitted stream is accompanied by one or more applications defined in one or more data carousels formed of data file and directory objects sent in cycles with predetermined groups of file and directory objects being formed into respective modules at the transmitter and with each module being transmitted as a whole. For each object carousel defining the root hierarchy of the data objects there is transmitted in the stream a list of identifiers for the component data carousels respectively defining all or a part of the data objects associated with an application. The receiver (14) is arranged, on identification of a particular application to be recorded, to use the list of identifiers to identify and subsequently store the received file data and directory objects for that application.

Abstract: A transmission system comprises a transmitter (10) and at least one receiver (14) configured to receive signals transmitted therefrom. Carousel-forming data file and directory objects are sent in cycles, with predetermined groups of file and directory objects being formed into respective modules at the transmitter, suitably according to MPEG-2 DSM-CC protocols. Each of the modules is transmitted as a whole, and the receiver is arranged to record received file data and directory objects under a predetermined grouping formulation, at elementary stream or module level.

Abstract: A method of, and apparatus for, encoding and multiplexing a digital video picture are provided using intra-coded fields only at a relatively high bit-rate, with each picture being encoded as a sequence of slices from the video image field. The encoding suitably complies with MPEG or similar requirements, and the intra-coding is further constrained so that the maximum number of bits for each slice in the picture is limited, and the delivery schedule of the bits to a decoder is more tightly constrained than is implied by the MPEG decoding models. In this way it is possible to build a high quality, low cost MPEG (or similar) encoder and decoder for video communications over digital interconnection standards such as IEEE 1394.

Abstract: Various methods are disclosed for producing an edited MPEG audio/video stream from first and second streams recorded in a transport-stream format normally intended for broadcast purposes. According to one implementation, a bridge sequence is generated which recodes data from both of the original streams, in the region of the edit point. Padding packets are inserted in the elementary streams to adjust a continuity counter values so as to allow continuous decoding across the join between bridge sequence and second sequence proper. In another implementation, seamless playback is not required, the bridge sequence is omitted, and various process are implemented “on-the-fly” to generate an edited stream compliant with MPEG-2 specification. To this end, exit and entry points are constrained to certain types of coded pictures, and offset between time-bases is adjusted to avoid buffer overflow.