MXPA00001833A - Method and apparatus for the reproduction of digital data streams - Google Patents

Abstract

In DVB/MPEG transport streams, the PID specifies the assignment of the packets to the different elementary streams. For reproduction of the elementary streams, for instance by a set-top box with outputting via the screen of a television set, the packets of the desired program have to be selected from the transport stream by means of the PIDs using the demultiplexer. This requires in each case the evaluation of the Program Association Table and Program Map Table, and also that the PIDs of the elementary streams to be reproduced be known to the demultiplexer in the set-top box. If the set-top box has a digital interface via which parts of the transport data stream can be stored and reproduced later or via which an arbitrary transport data stream can be fed to the set-top box, the demultiplexer must firstly be reprogrammed with the PIDs. Reproduction simply by the pressing of a reproduction (play) button is possible according to the invention;however, by virtue of the fact that the PID for the packets of at least one of the data streams is set to a predetermined value in the set-top box, the packets with this predetermined value of the PID being selected for reproduction.

Description

METHOD AND APPARATUS FOR THE REPRODUCTION OF DIGITAL DATA CURRENTS DESCRIPTION OF THE INVENTION The invention relates to a method and an apparatus for the reproduction of digital data streams, in particular for the reproduction of MPEG data streams.

Prior art Various methods are known for transmitting compressed bit streams of data. Such a method for MPEG2 data transmission has been specified in the MPEG2 specification Part 1: Systems (ISO / IEC DIS 13818-1). In this case, the encoded data is not transmitted as a direct current but is subdivided into small units of information called packets. This packet formation allows, on the one hand, the synchronization of the data streams, and on the other hand, the union of a plurality of data streams to form a new data stream. Depending on the type of transmission and / or application, the data is transmitted either in the program stream or in the transport stream. For radio transmission by satellite or terrestrial cable, the data stream is used since they have a particularly strong structure in the form of short packets. In this case, a transport packet is divided into a header comprising four bytes, optionally within an adaptation field and also within the useful information area. Thirteen bits of the header are used for the so-called packet identification. The packet identification (PID) in this case serves to assign the packets to the different elementary streams, the packets belonging to one and the same elementary stream having identical PIDs. The PIDs under which a corresponding coding device can find the individual packets within the transport stream are transmitted as part of the useful data in the form of the frames. In this case, the Program Association Table specifies the number of programs contained in a transport stream and defines the PID assignment to the Program Map Table for each of the programs. The Program Map Table in turn contains a list of all the PIDs for the elementary streams that are associated with the program assigned to the table. For the reproduction of elementary streams, for example by means of an installation box with output through the screen of a television set, the packages of the desired program have to be selected from the transport stream by means of the PIDs using a smul t ipl exor. This requires in each case the evaluation of the Program Association Table and the Program Map Table, and also that all the PIDs of the elementary streams to be reproduced are known from the one of smu 1 t ip 1 exo r in the installation box . If the installation box has a digital interface by means of which part of the transport data stream can be stored and reproduced later or by means of which an arbitrary transport data stream can be fed to the installation box, the smul t ip 1 exo r must be reprogrammed first with the respective PIDs after the evaluation of the Program Association Table and the Program Map Table. Therefore, playback is not possible simply by pressing a play button (r ep r o r).

The invention is based on the object of specifying a method for the reproduction of digital data streams in which any data streams can be reproduced in a simple manner by means of an installation box. This object is achieved by means of the method specified in the Rei indication 1. The invention is based on the additional object of specifying an apparatus for carrying out the method according to the invention. This object is achieved by means of the apparatus specified in Claim 4. In principle, the method of the invention for the reproduction of digital data streams, a plurality of data streams that are joined to form a stream of transmission data for transmission and the data that are grouped in packets, a packet containing, in addition of the useful information, the packet identification information, which specifies which data stream of the packet is allocated, which consists in the fact that the packet identification information for the packets of at least one of the data streams they are set for a predetermined value which differs from the original value, and that the packets with predetermined value of the packet identification information are selected for reproduction. Advantageously, of the transmission data stream, using the packet identification information, one or more data streams are selected and recorded and, before reproduction, one of the data streams, the identification information. of packages is set to default values. The method should preferably be applied if the data transmission stream is a DVB transport stream, for the change in value of the packet identification information first of the Program Association Table and the Program Map Table are evaluated and the information The identification of the package of video, audio and packets PCR is fixed to predetermined values.

In principle, the apparatus of the invention for the reproduction of digital data coments has an input for a transport data stream, a data type 1 e x or r to select data from the transport data, a decoder to decode the data contained in the data streams, and an output to output the coding data to a reproduction apparatus, as well as a transport current filter, by means of which the current of transport data may be read in and / or issued in whole or in part and a unit for re-labeling the package identification information, whereby the package identification information for the packages of at least one The data from the data is set to a predetermined value that differs from the original value, where the value of smu 1 t ap pl e r selects the packets with the default value of the identification information of package for reproduction. Preferably, a digital interface according to the IEEE 1394 Standard is provided additionally, which is connected to the transport interface, the digital interface that converts the transport data stream into the IEEE 1394 format.

Disclosures An illustrative embodiment of the invention is described with reference to the figure, which shows a simplified block diagram of the apparatus according to the invention.

Illustrative Mode The figure illustrates a possible embodiment of an apparatus according to the invention. An RF received television signal is the first of all fed to a DEMOD demodulator at the analog front end. This demodulation depends on the modulation method used and therefore on the respective transmission channel. In the case of satellite transmission, QPSK modulation and demodulation, in particular, are considered in this context. The demodulated signals are fed first to the EDC error correction and then to a TINT transport stream interface. The transport current interface TINT filters one or more programs, according to the stipulation of the user, outside the transport stream for recording on a digital storage medium based on disk or tape, for example a hard disk. This can be done by entering the associated PID numbers of the program or programs. In the same way, the selection can be made in an alternative way using a suitable menu displayed on the screen of the television set. The transport stream Pl for the selected programs is then fed by means of a suitable digital interface DINT, which corresponds for example to the IEEE 1394 Standard, for a storage device (not illustrated here), for example a hard disk or a recorder D-VHS and it's recorded there. For a further reproduction of the stored data stream, the latter is read first from the storage device by all of the digital interface DINT and fed as a transport data stream P2 to the re-entry unit. REST. In this case, if there is a plurality of recorded programs, it is first necessary that all select the desired program or the desired transmission. The corresponding PID numbers for the audio and video data and PCR are then determined for the desired program by means of the association table and the Program Map Table. The transport stream packets with the determined PID numbers are then retyped by the REST reject unit, ie the packet identification in the header of the respective transport packets are changed to fixed numbers known by the system. The transport current r e-e t i t P3 is then fed to that of smu 1 t ip 1 e xo r DEMUX by means of the transport current interface TINT. The one of smu 1 t ip 1 exo r DEMUX no longer has to evaluate the Program Association Table and the Program Map Table for the reproduction of the recorded data stream, since the same PID numbers are always present due to the r e-e t i t ted by means of the REST r e-e t i unit, although they can advance the data stream directly to the decoder MPEG2 DEC. After the coding, the display on the television can be made. For this purpose, the television set can be connected to the installation box for example by means of a SCART cable. The REST unit preferably is integrated in an installation box, although it can likewise be integrated in a recording device such as, for example, a digital recorder to a digital one, a DVD-RAM or the television set. The invention can be used for example in the context of a television memory function. The latter allows alternate reproduction over time in the following way. In the case of an interruption during the observation of a television program, for example due to a telephone call, the user initiates a command for example by pressing a corresponding button on the remote control, which leads to the storage of the subsequent program parts. . For this purpose, the transport stream is emitted by means of the TINT transport interface and the DINT digital interface to a recording device, for example, an integrated hard disk and is recorded in the latter. Once the interruption has ended, the user issues an additional command to start the alternate playback with the time of the recorded program starting at the point of interruption and the program continues simultaneously to be recorded, for example until the end of the transmission sent. Therefore, simultaneously, the stored transport stream is read by means of the DINT digital interface and the currently receiving TINT transport stream interface is issued by means of the same interfaces. In the case of the transport stream that is read, the PIDs are in this case re-labeled in the manner described above.

Claims (5)

1. Method for reproducing digital data streams, a plurality of data streams that are joined together to form a stream of transmission data for transmission and data that are grouped into packets as a packet containing, in addition to useful information , a packet identification information, which specifies which data stream is assigned to the packet, characterized in that the packet identification information for the packets of at least one of the data streams is set to a predetermined value that differs of the original value and in which packets with the predetermined value of the package identification information are selected for reproduction.

2. Method according to the claim 1, characterized in that the transmission data stream, which uses the packet identification information, one or more of the data streams are selected and recorded and, before the reproduction of one of the data streams, the Package identification is set to default values.

3. Method according to claim 1 or 2, characterized in that the transmission data stream is a transport stream, for the change in the value of the packet identification information first of all of the Program Association Table and the Table of Program Map are evaluated and the identification information of video, audio and packet package is fixed to predetermined values.

4. Apparatus for reproducing digital data streams according to one of claims 1 to 3, having an input for a transport data stream, a smul t ipl exor to select the data streams for the data stream of transport, a coding device for decoding the data contained in the data streams and an output for outputting the coding data to a reproduction apparatus, characterized in that a transport stream interface is provided, means by which the transport data stream can be read in and / or emitted in whole or in part, and a unit for labeling the packet identification information by means of which the packet identification information for the packets of at least one of the data streams is set to a predetermined value that differs from the original value, and in that of smu 1 tip 1 exo r selects the packets with the value or predetermined package identification information for reproduction.

5. Apparatus according to claim 4, characterized in that a digital interface according to the IEEE 1394 Standard is additionally provided, which is connected to the transport current interface, the digital interface converts the transport data stream into the format IEEE 1394.