FI98423C - Encoding the multimedia program's service components in a digital radio channel - Google Patents

Description

98423

The invention relates generally to the transmission of a multimedia program as a digital broadcast from a transmitter to a receiver, and in particular to the mutual arrangement and synchronization of parts of a multimedia program and the transmission of these operations via a digital radio channel.

10 Digital Audio Broadcasting (DAB) is a new type of transmission system which, over time, is intended to replace the current amplitude and frequency modulation transmission systems currently used for large-scale broadcasts. Its definitions are outlined in ETS 300 401 of the European Broadcasting Union (EBU) and the European Telecommunications Standards Institute (ETSI). To illustrate the background of the present invention, the following is a brief description of the features of the DAB system which: are essential to the invention.

One signal stream transmitted by a standard transmitting device forms a DAB ensemble 1, which may include several services 2, 3, 4 (service) according to Figure 1. Each service corresponds to one radio channel of the current systems from the user's point of view and consists of one or more service components:; '; tista 5, 6, 7, 8, 9, 10 (service component). The individual service component 5 may include, for example, an audio portion provided by the service 2, such as music, or some '···. an associated piece of data, such as the lyrics of the currently playing song, or other • · · information related to service 2. One service component 6 may be part of a multi-. . employs service 2, 4. The most important service component for the service is called • · · ··· / primary service component and the other service components belonging to the service φ · · *. * * 30 are called secondary service components ·: ·· (secondary service component) . The primary service component is often the audio portion provided by the service .... ·, but it can also be some data portion. The service may also contain, *, several audio sections as service components. Figure 1 shows the connection: ·; between each service (e.g. Radio A; 2) and its primary service component (in this case • Audio; 5) with a thick line.

The information transmitted from the transmitter to the receiver over the radio interface of the DAB system is divided according to its purpose into three channels 98423 2, as shown in Figure 2, which are a service channel 11 (MSC), a fast information channel 12 (FIC) and a synchronization channel 13. ). The above-mentioned service components 5-10 are transmitted in the service channel 11, which is further divided into separate convolutionally encoded subchannels 5 (11a, 11b, 11e, 1Id, 1e1 in Fig. 1). Each subchannel may transmit one or more packet mode service components. The relative order of the service components and subchannels is called a multiplex configuration. In particular, the high-speed information channel 12 contains information on said multiplexing configuration (MCI), but it can also be used to quickly transmit other information from the transmitter to the receiver. The synchronization channel 13 is used to control the transmission and reception operations of the system, such as the synchronization of transmission frames.

15 The Fast Information Channel (FIC) is intended for the rapid transmission of information from the transmitter to the receiver. As shown in Figure 2, the fast information channel comprises its own portion 12 of the transmission frame 14. The portion consists of FIB blocks 15 (Fast Information Block), which may be 3, 4 or 12 and each of which is 32 bytes or 256 bits in length. Figure 2 further shows 20 one FIB block 15 in which the first 30 bytes 15a comprise data and the last two bytes form a 16-bit CRC error checking section 15b. The data portion 15a is further divided into FIG groups 16, 17, 18 (Fast Information Group), and if these · ': do not fill the entire data portion, it has an end character 19 at the end and possibly:. ·. padding bits 20. The data portion of one FIB block may comprise one or more FIG groups, depending on how long the FIG groups are. One FIG group 17 comprises a 3-bit type identifier 17a, which is a binary number between 000 and 111, a 5-bit length detector 17b and a data field 17c. The length indicator 17b is an unsigned binary number, the value of which corresponds to some decimal number between 1 and 29, and which expresses the length of the data field 17c in bytes.

C:: 30 .... i The type identifier 17a determines the type of information the data field 17c contains. The most important for the invention is the FIG type 0 (type code 000), which is specially reserved for the transmission of the multiplexing configuration and the service information (SId) and whose data field structure is shown in more detail in Figure 3. first three so-called. flag bits, which are C / N bit 21, OE bit 22 and Id bit 23, followed by a five-bit so-called an extension field 24, which actually determines how the data part 25 of the FIG group is to be interpreted. The use of flag bits 21-23 is shown in the standard ETS 300 401 and is not a list relevant to the invention. The five bits of the extension code 24 can indicate 32 different interpretations, not all of which are defined. Unspecified interpretations are for future extensions of the system. Since the type identifier 17a and the extension identifier 24 of the FIG group together uniquely identify the FIG group used for a particular purpose, such a group is referred to by a designation using the decimal system equivalents of the symbols separated by a slash. For example, a FIG group of type 000 with an extension of 00010 is referred to as FIG 0/2.

In particular, FIG 0/2 type groups and how they are used to describe the services and service components contained in a particular DAB entity are discussed below. Figure 4 shows a data part 25 of a FIG 0/2 type group at the top. It is divided into successive sections, each of which describes one service, as shown. The figure shows the sections 26, 27 and 28 of the three different services separately.

The sections may be of different lengths depending on whether they use 16-bit or 32-bit Service Identifiers (SIds) as described below, and how many service components each service contains. The figure shows in more detail the portion 27 of the kth service. It includes, from left to right, a 16-bit or 32-bit Service Identifier (SId) 29, which uniquely identifies the service in question using the Radio Data System (RDS) specification. In accordance with EN 50067, certain country and type codes and the service reference number,: '; - a one-bit Local flag 30 indicating whether it is; . . service available in the coverage area of the entire DAB entity or locally, 25 «· · '! j. * - a three-bit Conditional Access Identifier (CAId) 31 which, according to a specific code table, indicates whether the service in question is encrypted and, if so, which encryption method is used, • · · • · · • · · · · - a four-bit number of components 32, which is an unsigned binary number indicating .... · how many service components (up to 12) the service in question contains, and • · - one or more 16-bit component description fields 33, 34, each for one of the services in question; service component.

The number of component description fields 33, 34 is the same as the number of service components of the service in question indicated in the destination field 32. The structure of one component description field 34 is further shown in more detail in the figure. It has a first two-bit transport mechanism identifier, or TMId (Transport Mechanism Identifier) 35, which indicates in which channel and in which mode the service component in question is transported. The value "00" of the TMId parameter corresponds to the audio transmission carried in the main service channel (MSC) and the current mode, the value "01" corresponds to the data transmission carried in the service channel and the current mode, the value "10" corresponds to the so-called fast information channel. The service component carried in the FIDC part (Fast Information Data Channel) and the value "11" correspond to the data transmission carried in the service channel and the packet mode.

Figure 4 further shows what information is transmitted by the last fourteen bits of the component description field 34 for each TMId parameter value. Corresponding to the value of the TMId parameter "00", the six bits following the parameter contain the so-called ASCTy parameter (Audio Service Component Type) 36, i.e. information on the nature of the sound of the audio transmission in question. Only the values "000000" and "000001" are reserved for 15 foreground sound and background sound; other values are left for future applications. The next six bits form a Subchannel Identifier 37 (SubChld), which indicates in which subchannel of the service channel the service component in question is transmitted. At the end of the section, there are two flag bits, of which the P / S flag (Primary / Secondary) 38 indicates whether the service component in question is a primary (value "1") or a secondary (value "0") component, and a CA flag (Conditional Access). 39 indicates whether the service com in question; ‘: Component encrypted (value“ 1 ”) or not (value“ 0 ”).

:. Corresponding to the value of the TMId parameter "01", the six bits following the parameter si-. ". '25 contain the type parameter 40, i.e. the information on the nature of the data transmission in question. If the service-specific part higher in the hierarchy is used. The 16-bit service identifier 29, type parameter 40, is always interpreted as a data service component type (DSCTy), in which case only the values: "000000", "000001", "000010" and "000011" are so far reserved for certain standards. · · V; 30 If the service identifier 29 is 32-bit, the type parameter 40 is interpreted as a Service Specific Specific Component (SSCTy), in which case its meanings are defined on a service-specific • ♦ identifier 37 and flag bits 38 and 39 are used in the same manner as above.

: 35 Corresponding to the value of the TMId parameter "10", the six bits following the parameter contain the type parameter 40 defined as described above. The next six bits contain the FIDCId parameter 41 (Fast Information Data Channel Identifier), which defines the location of that service component in the fast information channel 98423 5 FIDC using certain information referring to the structure of this section, which is presented in ETS 300 401. Flag bits 38 and 39 are used in the same way as above.

5 Corresponding to the value of the TMId parameter "10", the bits following the twelve parameters contain a Service Component Identifier (SCId) 42, which is unique within a particular DAB entity and which identifies a particular packet-switched service component. Flag bits 38 and 39 are used in the same manner as above.

10

Of the other types of FIG groups, mention is made here of FIG 2-type groups which are reserved in ETS 300 401 for a purpose not specified in more detail, but which have been proposed for use in arranging the synchronization of the service components.

15

The features of the DAB system related to the description of the services and the service components contained therein, as well as their mutual order, have been described above as prior art. In order to clarify the entire background of the invention, the transmission of multimedia programs on a digital radio channel will be further described to the extent necessary for an understanding of the invention.

. Multimedia usually refers to an audiovisual presentation presented to a specific user or with user interaction, which contains several so-called monomedia sections, each of which is information conveyed by a specific single media. In simple terms; 25 multimedia programs can have, for example, an audio part containing music and * · · ·;! / Synchronized still images. More complex multimedia programs often include »* * * · * 'the possibility of interaction with the user, so that the user can influence the course of the program by his own choices. From the point of view of the structure of the program, the interacting parts usually consist of links pointing from certain parts of the program: 30 to others, which are activated only if the user makes a corresponding selection.

It is generally advantageous to transmit parts of a multimedia program over a data connection.

f I

as jobs or files. Stream refers to a time-continuous entity that •, · is presented as it is transmitted to the receiving device, and the data: 1 ·. 35 means a data structure of a predetermined size and shape which is transmitted in whole or in part over a communication link and stored in a receiving medium on a storage medium for later use.

98423 6

In order to process multimedia programs at an abstract level, ISO / IEC standard 13522 has been created, which has 5 parts so far and is hereinafter referred to as the MHEG (Multimedia Hypermedia Information Coding Experts Group) standard, and in which the multimedia program is defined as. as a whole of objects.

5 Said objects are understood to be object-type, ie object classes whose members are objects according to class-specific definitions have been defined according to a certain syntax. Object categories include, for example, links, action objects, composition objects, content objects, and container-tainer objects. Certain objects may be continuous in time, in which case they are called streams. In addition, the objects may be interleaved, i.e. the multiplexed object consists of two or more streams, called component streams. These can still be multiplexed, i.e. contain more streams.

15 In order to produce a multimedia presentation using objects in accordance with the MHEG standard, a special tool is required which is able to process or interpret the objects, arrange the relations between them correctly using said numerical references and direct their presentation to the user. This device is known in English as the "MHEG engine" and is hereinafter referred to as the MHEG-20 engine. It is usually implemented programmatically and its operation is generally defined in the MHEG standard.

. . Hypertext applications are also known as the HTML programming language (HyperText;.. Markup Language), which can be used to implement a variety of multimedia programs. These ; V 25 consist of software components in file format, the execution of which • «1 * I1. ’Displays text and images and between which you can navigate and establish t · · links using the links placed on them. An HTML application running on a multimedia-equipped computer may also include audio files. The MHEG engine is equivalent in IA: HTML to an HTML driver (HTML browser), a program that can read «· 1 V: 30 HTML files and track their execution.

li · ..In the future will probably be transmitted a variety of multimedia and hyper-. text applications also via the DAB system. A multimedia service is similar to: i as other services in that it can be transmitted as part of a DAB entity, it may comprise one or more service components and may be subject to the same program type description, program numbering, start-up trigger, notification, naming, linking, and regionalization practices than for other services. However, the DAB system does not define all the functions and 98423 7 data structures required to start a multimedia program and synchronize it between its parts.

The first problem is that, within the current configuration, the receiver cannot deduce from the DAB service whether it contains a multimedia program or not. The mere calculation of the service components does not provide reliable information, because it is possible to transmit a certain audio portion in one audio service component and the associated image files of the two synchronization information of the same service component in the so-called in the Program Associated Data (PAD) or in the audio frames of another service component defined as an au-10 diode-form secondary service component. A multimedia program that looks like an out-of-print multimedia program is called self-contained multimedia. Even if a multimedia program comprises several different service components, the so-called in the service trigger phase, the DAB system does not yet transmit to the receiver a service identifier (SId parameter) on the basis of which the receiver could interpret from the contents of the FIG 0/2 group which different components belong to the same service.

Another problem is that the DAB system does not define a mechanism for transmitting to the receiver information about which interpretation and synchronization mechanism (FIG. 2, HTML, MHEG) is used to present the multimedia program. If the instructions required for synchronization are transmitted outside the groups of FIG. 2, the receiver «. nor can it be known from current configurations whether they are transmitted in a rapid in-. . in the FIDC part of the formation channel (i.e. in FIG 5 type groups), in the page information part (PAD part) of the program of the primary audio channel, as its own packet formats *. V 25 as its second service component or as current data transmission. The third, slightly ♦ 4 * * !! / similar problem is that the receiver also cannot know which of the proposed file transfer protocols is used to transfer files containing parts of a multimedia program. The protocols known to a person skilled in the art for transferring files i .: 1 In a DAB system from transmitter to receiver are the so-called Bosch / Nokia protocol V: 30 and the so-called Fraunhofer protocol. Of these, the former is described e.g. at the time of filing this application in the secret applicant's Finnish patent application 952879 .. ("Transfer protocol for transmitting files in the DAB system") and in the same applicant's Finnish patent application "Encoding of file segments in a digital radio channel" filed at the same time as this application.

It is an object of the present invention to provide a method by which information on the multimedia nature of a particular service, the instructions used to synchronize it and the protocol used to transfer its sub-data files can be transmitted to a receiver of a digital radio channel, preferably a DAB receiver. It is also an object of the invention that the implementation of the method according to it does not conflict with the standards of the DAB system. It is a further object of the invention to provide such a method, the implementation of which is simple and which does not cause an unreasonable computational load to the transmitter and receiver equipment 5.

The objects of the invention are achieved by defining two new types of service components within the DAB system and by appropriately selecting the data parts to be used to express them.

10

The method according to the invention for describing a multimedia program transmission service and its service components in a digital broadcasting comprising an information channel, characterized in that the method generates a type parameter 20 corresponding to the primary service component of the multimedia program transmission service. where part of said digital broadcast transmits instructions describing synchronization between parts of said multimedia program, j; and said type parameter is included as part of said information channel:: ': a portion describing said service component, which is the primary service component of the service transmitting the multimedia program: 25.

• i · • · · • ·

According to the invention, the most suitable object for making the further determinations required; To solve the above problems, the parameters ASCTy (Audio Service Component Type) and DSCTy (Data * \ * 30 Service Component Type) and possibly SSCTy (Specific Service Component) are the types of service components.

Type). In the foregoing description of the prior art, the location and principal use of these parameters in the service component descriptions included in the FIG 0/2 group have been described. The length of said parameters in bits is large enough to encode the necessary amount of multimedia information. They also have a sufficiently large number of hitherto undefined bit combinations so that the determinations according to the invention do not overlap with determinations made for any other purpose. Since current DAB receivers are programmed to ignore those service components whose type description has not been previously defined, the use of the method of the invention does not cause any changes or inconveniences in the use of existing receivers. The new DAB receivers are easy to program to identify the type descriptions according to the invention and to interpret multimedia programs with them.

5

According to the invention, in the case of an audio-type primary service component, the new parameters indicating the type of service component preferably include - information on whether the service component belongs to a multimedia program, 10 - information on whether the program page information part the information carried in the audio data portion of the audio frame in 15 file formats and, if so, the procedure used to mark the part to be distinguished as a file for identification, and -if the service component is part of a multimedia program carrying instructions for synchronizing that multimedia program.

20 •: In the case of a data-type primary service component, the new parameters indicating the type of service component preferably include information on whether the service component comprises multimedia data, information on the location of the synchronization mechanism:: ': and information on the protocol used for file transfer, iii 25. *: ’; The invention will now be described in more detail with reference to exemplary preferred embodiments and the accompanying drawings, in which Figure 1 shows the structure of a known DAB entity, Figure 2 shows the structure of a known DAB assembly. a known DAB system transmission frame and its distribution into channels, * '' Figure 3 shows a known DAB system FIB block structure, 35 Figure 4 shows a known FIG 0/2 array configuration, and 98423 10 Figure 5a shows the invention. the location and structure of the ASCTy parameter according to the invention in the case of the primary service component, and Figure 5b shows the location and structure of the ASCTy parameter according to the invention in the case of the secondary service component.

In the above description of the prior art, reference is made to Figures 1 to 4, and in the following description of the invention and its preferred embodiments, reference is made mainly to Figures 4 and 5. In the figures, the same reference numerals are used for corresponding parts.

10

First, the definition of an ASCTy parameter referring to an audio service component is discussed in accordance with the invention. According to the invention, the ASCTy parameter 36, which unambiguously refers to a particular service component, should be formulated differently in the case of the primary and secondary service components. In a Multimedia-15 program, the synchronization mechanism, or at least information about its location, must be carried in the primary service component. The receiver identifies the primary service component of a particular service according to the prior art from a particular F1 0/2 group lip pubit described above.

Figure 5a shows a division according to a preferred embodiment of the invention, by which the six-bit ASCTy parameter 36a of the primary audio service component is divided into: fields of one and two bits, which have their own meaning. The:: ASCTy parameter is located in a manner known per se in the bit positions of the description components comprised by the FIG 0/2 group •: ’: in the description portions of the service components; 25 bl3-b8, where the TMId parameter includes the first two bits (bits bl5 and bl4) • »· i. ·: *. are "00". In the division of Figure 5a, the fields are from the left,. - XPAD file field 43: • · · *; |: The flag bit used to indicate whether files are transferred in the page information (*) part (PAD part) of the program in the audio frames of the audio service components of the audio format in question. The portion of the PAD- · :·· belonging to each audio frame comprises, in a known manner, a fixed part (F-PAD, Fixed PAD) and possibly. . an extended PAD (X-PAD), the latter of which can be used to transport files. In a preferred embodiment of the invention, the value "0" in the XPAD file field 43 of the ASCTy parameter 35 indicates that no files are carried in the X-PAD portion of the frames, and the value "1" indicates that files are carried in the X-PAD portion of the frames. The files carried in the X-PAD part can be quite independent of the audio part of the service component, so it is good to indicate their existence in the fast information channel according to the invention.

- Audio file field 44: 5 A two-bit field used to indicate whether a particular piece of data transmitted by audio frames is intended to be stored as a file on the receiving device and, if so, by what mechanism that part of the data is assigned. The values according to a preferred embodiment of the invention and their interpretations are shown in the following table:

Table 1 0 0 audio frames do not contain data sections to be stored as a file 0 1 audio frames contain data sections to be stored as a file, which are indicated by the mechanism carried in the X-PAD part_ 1 0 audio frames have data sections to be stored as a file, which are indicated in FIG 2/0 - the mechanism carried in groups_ 1 1 audio frames have portions of data to be stored as a file, which are indicated by the mechanism carried in a packet-shaped subchannel._ <

In the latter case, the packet-based subchannel on which the mechanism used to assign the data shares is carried must be mentioned in the FIG 0/2 group describing the mutual organization of the service components.

»·» • «» »* ', · · - Multimedia / Ext. Flag 45 and type field 46: / Γ: Flag bit 45 indicates whether or not the primary service component in question is associated with a multimedia service. If the service is not a multimedia service, the value of flag bit 45 is; . *. 20 "0". In this case, the audio service component in question transmits to the usual way. ·: ·, Sound or audio files which may be reproduced in a broadcast and which are intended to be *> recorded and played only by the indication of the audio data sections referred to above; : as determined by the mechanism. In order to ensure that the definition of the values in type field 46 is not *** · inconsistent with the already standardized definitions, its values and interpretations in connection with the value "0" of flag bit 25 45 should be chosen as follows: 98423 12

Table 2 _ 0 0 service component is foreground sound _ 0 1 service component is background sound _ 1 0 service component is audio file stream 1 1 reserved for future extensions_

If the primary service component in question is associated with a multimedia service, the value of flag bit 45 is "1". In this case, it is preferable to define the values and interpretations of the type field 46 as follows:

Table 3 _ 0 0 service component is an audio program stream, the multimedia sync mechanism is carried in the X-PAD portion of the audio frames 0 1 service component is an audio program stream, the multimedia sync mechanism is carried in FIG 2 groups_ 1 0 service component is a stream of audio files, transported in the X-PAD portion 1 of the audio frames, the service component is a stream of audio files, the multimedia synchronization mechanism is carried in groups of FIGS. 2 Here, an audio program stream means an audio stream which is' ·; “10 ka may comprise parts to be interpreted in the manner determined by the above-mentioned audio data portion assignment mechanism, but which can also be presented as such again. The correspondences between the bit combinations of the type field 46 and their interpretations are not: · per se relevant to the invention, i.e. the order of the second column of Table 3 can be changed. However, the presented correspondences are supported by the fact that according to them, the value 1 of the left (most significant) bit of the field to the left corresponds to the nature of the service component as a stream of audio files in the same way as the table • · · ·. ·: ·. in the case where the service is not a multimedia service.

: It should be noted that although the presented procedure does not support the marking of sound as the primary service component of a multimedia service as foreground sound or background sound, this is unlikely, as in a multimedia program the synchronization instructions usually contain information about which sound component should be directed to which speaker and at what volume.

Il 13 98423

Figure 5b shows a division according to a preferred embodiment of the invention, by which the six-bit ASCTy parameter 36b of the secondary audio service component is divided into fields having their own meaning. This ASCTy parameter is located in the service component description portions comprised by the FIG 0/2 group in the same manner as the ASCTy parameter 36a of the primary audio service component discussed above. In the division of Figure 5b, the two leftmost fields 43 and 44 are the same as above. The three-bit type field 47 is interpreted as in Table 2:

Table 4 0 0 0 service component is foreground sound _ 0 0 1 service component is background sound _ 0 10 service component is audio file stream other reserved for future extensions_ 10

Next, the definition of the DSCTy and SCTy parameters referring to the data service component in accordance with the invention will be discussed. The definitions are presented in Tables 5 and 6. It should be noted that the top four rows in each table correspond to already standardized interpretations.

15

Table 5: DSCTy_ b! 3 b8_ '0 0 0 0 0 0 paging messages _; : 0 0 0 0 0 1 Traffic Message Channel (TMC) _ · 0 0 0 0 1 0 Emergency Warning Systems (EWS) _ i 0 0 0 0 1 1 interactive text ITTS (Interactive Text Transmission System) • · * ” : 0 0 0 1 1 0 file transfer_ 1 0 0 0 0 0 service component associated with a multimedia program, synchronization *: _time mechanism is transported in FIG 2 groups_: ': *: 10 0 1 10 file transfer associated with a multimedia program, associated with a multimedia program, synchronization mechanism transported in the primary service • ·. _debt component_ t · · · 98423 14

Table 6: SCTy_ _b7_b0__ 00000000 paging messages _ 0 0 0 0 0 0 0 1 traffic message channel TMC (Traffic Message Channel) _ 0 0 0 0 0 0 1 0 Emergency Warning Systems EWS 0 0 0 0 0 0 1 1 interactive text ITTS (Interactive Text Transmission System) _ 0 0 0 0 0 1 1 0 file transfer using Bosch / Nokia protocol_ 0 0 0 0 0 1 1 0 file transfer using Fraunhofer protocol_ 1 0 0 0 0 0 0 0 the service component is associated with a multimedia program, the synchronization mechanism is carried in FIG 2 groups_ 1 0 0 0 0 1 1 0 in the service component file transfer using the Bosch / Nokia protocol, is associated with a multimedia program, the synchronization mechanism is transported in the primary service component 1 0 0 0 0 1 1 1 transfer using Fraunhofer protocol collage, associated with a multimedia program, the synchronization _mechanism is carried in the primary service component

The service component types shown in bold are only applicable to the primary service component of the multimedia service because they contain a synchronization mechanism or information about where the synchronization mechanism is carried. Again, the relative order of the bit combinations and their interpretations is not in itself essential to the invention, but the choices have sought a certain logic. For example:. · · The value "1" of the most significant bit of both DSCTy and SCTy (d3 in DSCTy and j | b7 in SCTy) indicates that the service component in question contains a synchronization mechanism or information on where the synchronization mechanism is carried, in which case it is the primary service component of a multimedia service. The second bit on the right:. (In DSCTy b9 and SCTy b1), a value of "1" indicates that the service component generates the file stream in the same way as in the case of ASCTy (cf. Tables 2, 3 and • · · 4).

15

Corresponding definitions according to the invention can also be applied to SSCTγ para-. ·. meter, although the values and interpretation of this parameter are left to the application.

20 The tables above show how a parameter describing the type of primary service component can include information on whether or not the service in question is 98423 15 multimedia. In addition, the interpretations of the parameter values shown in the tables indicate whether the instructions for synchronizing the multimedia service are carried in the FIG 2 groups or elsewhere. If the service is not controlled by FIG 2 groups, it is in MHEG or HTML format under the current conditions, in which case the links and script instructions controlling its progress are included in several files. One of these files is the so-called startup file containing instructions for starting the program. The state of the art and previous Finnish patent applications of the same applicant are known for procedures for causing a receiver to identify a startup file and a file description describing it, which is a certain type of data-10 group to be transmitted with the transmission (see e.g. Finnish patent application 952880, "Multimedia objects transmission in a digital communication system "). A particular parameter in that file description indicates whether the startup file is of the HTML or MHEG type. Based on this, the receiver starts an HTML driver or MHEG engine stored in its memory media, which starts playing the multimedia program.

15

The invention shows for the first time how in a DAB system information can be transmitted to a receiver of a digital radio channel about the multimedia nature of a certain service, the instructions used for synchronizing it and the protocol used for transferring its subfiles. Since the invention per se uses data structures belonging to the standards of the DAB system, but left undefined, the implementation of its method does not contradict the standards of the DAB system.

: '': The mechanisms for generating and interpreting the parameters of the invention are readily available. ·. to be added to DAB systems known per se and dealing with other parameters:. ·. and its simple implementation with a few bits does not cause transmitter and receiver «I ·! ' V 25 unreasonable computational load for equipment.

t: :··· · • ·· • · · • · · • · · 1 ♦ «1 • 1« · «· • · · • · · · ·

Claims (16)

98423 A method for transmitting a multimedia type program in digital broadcasting, wherein the programs are transmitted as services (2, 3, 4), each of which comprises one or more service components (5, 6, 7, 8, 9, 10), of which 5 are one and only one is a primary service component (5, 8, 10), and said digital broadcast comprises an information channel (12) for transmitting information related to said service components, wherein the portion (33,34) describing each service component comprises parameters (35, 36) describing the service component , 37, 38, 39, 40, 41, 42), characterized in that the method generates a type parameter (36a, 40) corresponding to the primary service component of the multimedia program transmission service, which indicates - information (45) indicating that the multimedia program is a service component of the service, and 15 - information (46) on where said digital general instructions for synchronizing between parts of said multimedia program are transmitted in a portion of the broadcast, and said type parameter is included as part of said information channel 20 (34) describing said service component, which is the primary service component of the service transmitting the multimedia program. A method according to claim 1, characterized in that said mulch; The primary service component of the service that transmits the multimedia program is the audio format! Ύ 25 a second service component, in which case the information contained therein is transmitted in said digital ·; j .: in a digital broadcasting system as audio frames, each frame comprising an audio • · · diode data portion and a program side information portion. A method according to claim 2, characterized in that said: .5: 30 type parameter (36a) further indicates information (43) as to whether file format information is transmitted in the page information portions of the audio frame program of said audio service component. A method according to claim 2 or 3, characterized in that said type parameter (36a) further indicates information (44) on whether information in the audio data portion of the audio frames of said audio service component is transmitted as information to be stored in a file on the receiving device, and where 98423 a portion of said digital broadcast transmits an assignment mechanism for assigning information to be stored as a file. A method according to claim 2, 3 or 4, characterized in that said type parameter (36a) further indicates information (45) as to whether information in the audio data portion of the audio frames of said audio service component is transmitted to the user of the receiving device without recording. A method according to any one of the preceding claims, characterized in that said multimedia program transmission service further comprises a secondary service component which is an audio service component, the information contained therein being transmitted in said digital broadcasting system as audio frames, each frame comprising an audio data portion and a program side data portion. A method according to claim 6, characterized in that a type audio parameter (36b) is generated corresponding to the secondary audio service component of the service transmitting said multimedia program, indicating information (43) on whether information is transmitted in the page data portions of the audio frame program of said audio secondary service component. 20.:. A method according to claim 6 or 7, characterized in that said type parameter (36b) corresponding to the secondary service component further indicates information (44) as to whether audio frames of said secondary service component are transmitted. V in the audio data portion, information that can be stored in the receiving device; · ·. · 25 as a file, and if transmitted, in which part of said digital broadcast · ♦ 1: an assignment mechanism is transmitted to indicate the information to be stored as a file. • ·· ♦ · 1 • «· • Method according to any one of claims 6 to 8, characterized in that said type parameter (36b) corresponding to the secondary service component further indicates information (47) as to whether the m'mm of said secondary service component is transmitted. in the audio data section of audio frames, foreground sound, background sound, recordable audio • ·. file stream or other audio information. A method according to claim 1, characterized in that said primary service component of the service transmitting the multimedia program is a data-type service component, wherein the information contained therein is transmitted in said digital broadcasting system as data frames. 98423 A method according to claim 10, characterized in that said type parameter corresponding to the primary service component further indicates information on whether file-shaped information is transmitted in the data frames of said data service component. 5 A method according to claim 11, characterized in that said type parameter further indicates information on which file transfer protocol is used to transmit information in file format. A method according to any one of the preceding claims, characterized in that said service transmitting a multimedia program further comprises a secondary service component which is a data service component, wherein the information contained therein is transmitted in said digital broadcasting system as data frames. A method according to claim 13, characterized in that a type parameter corresponding to a secondary data format service component of the service transmitting said multimedia program is generated, indicating information on whether file format information is transmitted in the data frames of said data service format component and, if so, which file transfer protocol is used. to convey information. 1. A method according to any one of the preceding claims, characterized in that said digital broadcasting system is a DAB system and said type is. '.' the parameter is included in the service component-specific portions (32, 33, 34) of the information groups (17) of the type FIG 0/2; ':: 25 in the fast information channel of said DAB system. • · · • · m m A method according to claim 15, characterized in that said: type parameter is an ASCTy parameter, a DSCTy parameter, an SCTy parameter or an SSCTy parameter, depending on the transport mechanism of the service component it describes. • · 19 98423