WO2006129236A2

WO2006129236A2 - Method and apparatus for recording and trick playing interactive digital tv program

Info

Publication number: WO2006129236A2
Application number: PCT/IB2006/051640
Authority: WO
Inventors: Jingwei Tan; Jun Shi; Liang Gan
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2005-06-03
Filing date: 2006-05-23
Publication date: 2006-12-07
Also published as: WO2006129236A3

Abstract

The present invention provides a method and apparatus for recording and trick playing transport stream of interactive digital TV program, wherein the method for recording a transport stream of an interactive digital TV program, comprising steps of: determining whether there is version change of an interactive application's control information in said transport stream; and generating an accessory mark used to mark said version change. By employing the method and apparatus for recording and trick playing transport steam of interactive digital TV program as provided in the present invention, the processing capability of the player' s processor can be saved and the cost of the player can be reduced while maintaining interactivity.

Description

METHOD AND APPARATUS FOR RECORDING AND TRICK PLAYING INTERACTIVE DIGITAL TV PROGRAM

FIELD OF THE INVENTION

The present invention relates generally to interactive digital TV (television), and more particularly, to a method and apparatus for recording and trick playing interactive digital TV program.

BACKGROUND OF THE INVENTION

With the emergence of digital televisions and set-top boxes having storage capability, users expect to record digital TV programs easily just as they record analog TV programs by using an ordinary video recorder. Besides, a digital television generally contains accessory interactive applications in transmission. When trick playing the recorded digital TV programs, users expect the interactivity to be maintained.

The most direct approach to recording interactive digital TV programs is to store all transport streams to be broadcast. However, an interactive application is broadcast by way of object carousel. For example, in DVB - MHP (Digital Video Broadcasting - Multimedia Home Platform), an interactive application is composed of Java program files, which are multiplexed into a transport stream through DSM-CC (Digital Storage Media -

Command and Control) in form of object carousel and are transmitted repeatedly by carousel.

Teletext is a very good example of object carousel. The scene of the teletext system is presented repeatedly in the hidden lines of analog video signals. If the user wants to watch a particular scene, generally he has to wait until it is broadcast next time. The maximum time period is the time needed for a complete object carousel cycle. If the receiver wants to receive a particular file from the object carousel, it has to wait until the file appears in the object carousel next time. A simple storage of all received transport streams cannot guarantee the correctness of the interactivity during trick play sufficiently. Detailed reasons may refer to descriptions of Figure 1 and Figure 2.

Fig.1 schematically illustrates DSM-CC (Digital Storage Media - Control and Command) object carousel in a transport stream of an interactive digital TV program according to prior arts. As shown in Fig.l, suppose that the user turns on the TV at a certain time to receive the broadcast MHP interactive TV program from point A corresponding to Block 4. This means the data receiver of the TV starts to receive data from module bθ. But in fact the receiver just stores, instead of running, the data of module bθ, and keeps reading data from the broadcast transport stream until it receives the first DSI (Download Server Initiate), which corresponds to block 5. Then, the receiver will continue to receive the first DII (Download Info Indication), which corresponds to block 6. According to the information contained in the DSI and DII, the receiver will know that data modules a, b and c need to be stored and decoded. Afterwards, the data corresponding to block 7 and block 8 will be stored and decoded by the receiver. At the same time, the receiver needs to monitor the DSI and DII to see whether there is version change. Beginning from block 10, the receiver receives Dili. The information contained in Dili indicates that there is an updated version for modules b and c. The receiver will cache the new version bl carried in block 12 and replace the previous version bO with bl. Then, the receiver will replace the old version cO with module cl carried in block 16.

Fig.2 schematically illustrates a rewind play of a recorded DSM-CC transport stream. In this figure, three states are shown: "Rewind" means the player performs rewind operation on the stored interactive digital TV program; "Broadcast" means the receiver receives the broadcast transport stream; and "Ideally" means correct play under ideal conditions.

In the broadcast transport stream as shown in Fig.2, beginning from point Bl, two data modules bO and cO generate new versions bl and cl. To indicate the above change, a new version Dili is generated to replace DIIO.

Suppose that the user rewinds the interactive digital TV program from point A and stop the rewind to normal play at point C. At point A, the current versions running in the player are bl and cl. To maintain normal interactivity in the program, the player needs to parse the transport stream from point C to point A after completing the rewind operation, to keep checking DSI and DII to obtain the correct version information of the modules. From block 5 to block 9, the player parsed a0 and cO but did not parse module b. During this region there is no version change, so the player still uses version bl. Beginning from block 10, the player knows according to DSIIl that there are version changes of bl and cl, so it uses versions aθ, bl and cl from point Bl to point A. Suppose that the user rewinds the interactive digital TV program from point A and stop the rewind to normal play at point Bl. The information contained in blocks 17, 18, 13, 14, 9 and 10 is filtered in turn quickly. In this region, Dili has no version change. During rewind, fast filtering requires that the rewind system obtain interactivity immediately so as not to interfere with playing performance. In order to guarantee normal play from point Bl to point B2, modules aO and cO should be used instead of bl and cl (refer to "Ideally"). But before DSI and DII corresponding to blocks 5 and 6 are filtered, the player has no way of knowing that the version DII has been updated. Meanwhile, the player does not know that data contained in module cO is of its previous version. Only after DSI and DII in blocks 5 and 6 are filtered, did the player begin to realize that it should use modules bO and cO of the previous version. In order to guarantee correct play after the rewind operation, the player should filter module data forward instead of backward, to assure the correctness of the program status. But the filtering module does not know where in the front region to begin to filter module data so as to obtain the correct version of the module. For example, there are version changes soon after the program begins, then the filtering module needs to filter all data from the current position to the beginning of the program, to obtain the correct version information. In this case, the performance of the player cannot be guaranteed.

When the receiver is in the state of receiving the broadcast transport stream, modules aO, bO and cO are used from block 1 to block 11, modules aO, bl and cO are used from block 12 to block 15 and modules aO, bl and cl are used from block 16 to block 20, before the new version module bl corresponding to block 12 and the new version module cl are received.

However, when the interactive digital TV program is played under ideal conditions, the versions should be aO, bO and cO before point Bl, and the versions should become aO, bl and cl after point Bl. By comparing the three states, namely, "rewind",

"broadcast" and "ideally" shown in Fig.2, it can be seen that the player cannot obtain correct version information on time in the rewind operation status and that the interactive application cannot synchronize with the A/V stream when the user rewind plays the recorded digital TV programs. When the user carries out "rewind" operation (reverse play of the program), the player needs to seek forward the correct module data and decode it. This requires frequent checking of whether there are version changes of DSI and DSII. In Fig.2, for example, it needs to check the version states corresponding to blocks 5, 6, 9, 10, 13, 14, 17 and 18. This requires that the player have a very high processing capability. And thus the cost of the player will become relatively high accordingly.

Therefore, a low-cost method and apparatus for recording interactive digital TV program is needed so that interactivity can be maintained when the user trick plays the recorded digital TV program. SUMMARY OF THE INVENTION

The present invention provides a low-cost method and apparatus for recording and trick playing interactive TV programs. With the present invention, when the user trick plays a digital TV program, interactivity can be maintained and it can be synchronized with the A/V stream.

A method for recording transport stream of interactive digital TV programs as provided according to the present invention, comprises steps of: determining whether there is version change of an interactive application's control information in said transport stream; and generating an accessory mark, the accessory mark being used to mark said version change.

A method for trick playing a transport stream of a digital TV program as provided according to the present invention is used to trick play the transport stream by switching from a current point to a next play point, comprising steps of: reading an accessory mark, the accessory mark being used to mark whether there is version change of an interactive application's control information in the transport stream; determining whether there is version change of said control information from said current point to said next play point, according to said accessory mark; and processing said interactive application according to the control information version at the position of an accessory mark previous to said next play point if there is a change.

An apparatus for recording a transport stream of an interactive digital TV program as provided according to the present invention, comprises: determining means, for determining whether there is version change of an interactive application' s control information in said transport stream; and generating means, for generating an accessory mark, the accessory mark being used to mark said version change.

A playing apparatus for trick playing a transport stream by switching from a current point to a next play point is provided according to the present invention, comprising: reading means, for reading an accessory mark, the accessory mark being used to mark whether there is version change of an interactive application's control information in the transport stream; determining means, for determining whether there is version change of said control information from said current point to said next play point, according to said accessory mark; and processing means, for processing said interactive application according to the control information version at the position of an accessory mark previous to said next play point if there is a change. As described above, with regard to the method and apparatus for recording and trick playing interactive digital TV programs as provided in the present invention, it can save processing capability of a player's processor, reduce the cost of the player, and improve playing efficiency while maintaining interactivity. Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following descriptions and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.1 schematically illustrates DSM-CC (Digital Storage Media - Control and

Command) object carousel in a transport stream of an interactive digital TV program according to prior arts.

Fig.2 schematically illustrates a rewind operation on a transport stream of an interactive TV program according to prior arts. Fig.3 schematically illustrates object carousel of DSM-CC in a transport stream of an interactive digital TV program according to an embodiment of the present invention.

Fig.4 is a flow chart showing the method for recording interactive digital TV programs according to an embodiment of the present invention.

Fig.5 is a block diagram showing the apparatus for recording interactive digital TV programs according to an embodiment of the present invention.

Fig.6 is a flow chart showing the method for trick playing interactive digital TV programs according to an embodiment of the present invention.

Fig.7 is a block diagram showing the apparatus for playing interactive digital TV programs according to an embodiment of the present invention. Throughout all the above drawings, like reference numerals will be understood to refer to like, similar or corresponding features or functions.

DETAILED DESCRIPTIONS OF THE INVENTION

Detailed descriptions will be made below to specific embodiments of the present invention taken in conjunction with the accompanying drawings.

As shown in Fig.3, there are three kinds of information in a data carousel: DSI, DII and data modules according to an embodiment of the present invention. DSI is control information of DSM-CC. DSI includes service positioning information, namely, the root directory of the data in the module. DII is also control information of DSM-CC, for describing a group of modules and providing necessary parameters including parameter information required by the downloading module at the client side, including module version, module size, broadcast channels, and timing information of all blocks needed for constructing the modules. In Fig.l, DII includes two versions: DIIO and Dili , and includes parameters of modules a, b and c as well.

If version changes of DSI and DII are detected when the user records a transport stream of an interactive digital TV program, an accessory mark will be generated at the position where version 0 appears the first time and at the position where the first change occurs respectively, to mark the version change of DSI and DII. For example, DSI and DIIO corresponding to blocks 1 and 2 will be marked because DSI and DIIO are of the initial version 0. Similarly, Dili corresponding to block 10 will be marked because Dili is at a position where version change occurs the first time. The accessory mark includes position information for the transport stream whose control information has version change (for example, transport stream packet number = 5) and type information of the control information (for example transport stream type = DSII), which indicates that DSII at the position where transport stream packet number is 5 has version change.

The position information in the accessory mark may include but not be limited to the following kinds: TS (Transport Stream) Packet Number, SPN (Source Packet Number), time information such as UTC (Coordinated Universal Time) or PCR (Program Clock Reference) and etc. Similarly, the accessory mark may be linked to the nearest video I frame in the transport stream, thus to mark the position information of version change.

An example will be given to generating an accessory mark by using the transport stream packet number. The case indicated in Fig.3 may be written into a Mark_Description_File according to the following format.

<Mark_De scrip tion_File — >

<Mark

CONTROL_MESSAGE=DSI VERSION=O

MARK_TYPE = USING_PACKET_NUMBER

POSITION=I /Mark> <Mark

CONTROL_MESSAGE=DII VERSION=O

MARK_TYPE = USING_PACKET_NUMBER POSITION=2

/Mark>

<Mark

CONTROL_MESSAGE=DII VERSION=I

MARK_TYPE = USING_PACKET_NUMBER POSITION=10 /Mark>

/>

After recording a transport stream of an interactive digital TV program by using the above method provided according to an embodiment of the present invention, if the user rewinds the interactive digital TV program from point A to begin normal play at point C, the player can recognize that there is no version change of all data modules a, b and c from block

10 to block 20, namely, "Section Y", because version change of Dili corresponding to block 10 has already been marked when recording the transport stream. The player will use module versions bO and cO according to the DSI and DII (corresponding to blocks 1 and 2) information at an accessory mark previous to point C, i.e., the player will use modules bO and cO before point B 1. According to the method provided in the embodiment of the present invention, there is no need to check version change for every DSI and DII one by one from point A to point C and we only need to check the accessory mark where there are version changes. Therefore, the processing capability of the player's processor can be saved and cost of the player can be reduced as well.

Fig.4 is the flow chart showing the method for recording interactive digital TV programs according to an embodiment of the present invention.

Start to receive a transport stream of an interactive digital TV program at step S410. Filter the DSM-CC control information including DSI and DSII at step S420.

Determine whether there is a version change of DSI or DSII at step S430. If yes, for example, DSII changes from DSIIO to DSIIl, an accessory mark will be generated to mark the version change of DSI or DSII, and be written into a Mark_Description_File at step S440. If no, the process will jump to step S450.

Determine whether recording of the interactive digital TV program has been completed at step S450. If yes, end the process. Otherwise, the process will return to S410 to continue to receive the transport stream of the interactive digital TV program.

Fig.5 illustrates the functional modules of the recording apparatus according to an embodiment of the present invention. The recording apparatus comprises a generating means 510 and a determining means 530. The generating means 510 is operable to generate an accessory mark to mark the version change of DSI or DII in the DSM-CC control information. The determining means 530 is operable to check whether there is version change of DSI or DII in the DSM-CC control information in the transport stream. If yes, the generating means 510 generates an accessory mark, which includes the position information (for example, transport stream packet number = 5) of the transport stream whose control information has version change, and type information of the control information (for example, type of the control message = DSII). This example shows that there is a version change of DSII at the position where the transport stream packet number is 5.

The recording apparatus 50 further comprises a storage media 550, for storing the accessory mark generated above. In this embodiment, the accessory mark is stored in storage media 550 in form of a Mark Description File. The storage media 550 is also used to store the received transport streams. The recording apparatus 50 further comprises a filtering means 520, for filtering version changes of the DSM-CC (DSI Λ DII) control information in the received transport stream, particularly, the initial versions of DSI and DII and the first version change situation in the object carousel; a program receiving means 560 which may include a tuner (not shown in the figure) and a demodulator (not shown in the figure), for receiving the transport stream of the broadcast TV program; an input processor 570, for receiving the user input to perform various operations on the recording means 50, for example, the operation of recording the interactive digital TV program; and a program recording means 540, for recording the received transport stream into storage media 550. Fig.6 is the flow chart showing the method for trick playing interactive digital TV programs according to an embodiment of the present invention.

At step S600, start to trick play an interactive digital TV program, and receive the user input (for example, fast forward play), to obtain position information of the current point and that of the next play point to be switched, such as transport stream packet number.

At step S610, read an accessory mark, which is used to mark whether there is version change of the control information of the transport stream.

At step S620, filter the DSM-CC control information, which includes DSI and DSII. At step S630, determine whether there is version change of said control information between the current point and the next play point. If yes, obtain the control information version of the interactive application at the mark previous to the next play point at step S640.

At step S650, process the interactive application according to the control information version for the interactive application at the previous mark point.

As shown in Fig.3, if reverse play is done from point A (current point) to point C (next play point) and it' found after filtering and determinating that version change of DII (corresponding to block 10) is detected at point Bl, the player will obtain the version information of the mark (corresponding to block 2) previous to point C and process the interactive application according to this version information, that is, the data module versions from point A to point Bl are aθ, bl and cl and the data module versions from point Bl to point C are aθ, bO and cO.

Similarly, as shown in Fig.3, if fast forward is done from point C (current point) to point A (next play point) and it's found after filtering and determinating that version change of DII (corresponding to block 10) is detected at point Bl, the player will obtain the version information of the mark (corresponding to block 10) previous to point A and process the interactive application according to this version information, that is, the data module versions from point C to point B 1 are aθ, bO and cO and the data module versions from point Bl to point A are aθ, bl and cl. At step S660, determine whether the play has been completed. If yes, end the process. If no, return to step S620 and continue to filter DSM-CC control information.

Fig.7 shows the functional modules of the playing apparatus according to an embodiment of the present invention. The playing apparatus 70 can trick play interactive digital TV programs, comprising: a reading means 720, for reading a transport stream and an accessory mark, the accessory mark being used to mark whether there is version change of the control information of the transport stream; a determining means 710, for determining whether there is version change of said control information, especially for determining whether there is version change of the control information from a current point to said next play point during trick play; and a processing means 730, for processing an interactive application according to the accessory mark. Also, the processing apparatus 730 is used to decode audio/video in the transport stream. The mixture of the audio/video and the interactive application information will be presented to the user through a display means (not shown in the figure).

The playing apparatus 70 further comprises a location positioning means 740, for obtaining the position information of the current point and the position information of the next play point to be switched, such as the transport stream packet number, and for positioning in the audio/video transport stream to find the interactive application file of the corresponding version according to position information in the accessory mark, for example, the DII version changes from DIIO to Dili at the position of the program time reference 00 : 08: 45.

This playing apparatus 70 further comprises a controlling means 750, for receiving a user input. The user input may include a request, for trick playing a transport stream in a particular mode (for example, fast forward play). The request may also include the position information of the next play point (for example, the position information of the next play point for reverse play).

This playing apparatus 70 further comprises a storage media 550, for storing a transport stream of an interactive TV program and a mark description file. It is to be understood by those skilled in the art that the storage media 550 disclosed according to an embodiment of the present invention may include, but not be limited to HD (Hard Disk), DVD+RW, BD (Blue-Ray Disk) and etc.

It is to be understood by those skilled in the art that the recording apparatus 50 and playing apparatus 70 may be incorporated in a set-top box or a TV set.

The method and apparatus for recording and trick playing interactive digital TV programs as disclosed in the present invention may be used not only for reverse playing an interactive digital TV program, but also for other unusual play, or namely, trick play. In the present invention, the trick play includes Fast Forward, Fast Backward, Last One, Next One and Reverse Play.

It is to be understood by those skilled in the art that the method and apparatus for recording and trick playing interactive digital TV programs may be used not only in digital TV programs in DVB (Digital Video Broadcasting) format, but also may be improved without departing from the basis of the present invention to be applied to digital TV programs in other formats, such as ATSC (Advanced Television Systems Committee) and ISDB (Integrated Services Digital Broadcasting) and etc.

It is to be understood by those skilled in the art that various improvements and modifications can be made to the method and apparatus for recording and trick playing interactive digital TV programs without departing from the basis of the present invention.

Therefore, the scope of protection of the present invention is to be defined by the attached claims herein.

Claims

CLAIMS:

1. A method for recording a transport stream of an interactive digital TV program, comprising steps of: determining whether there is version change of an interactive application's control information in said transport stream; and generating an accessory mark for marking said version change.

2. The method according to claim 1, wherein said accessory mark includes corresponding position information of the transport stream when there is a version change of said control information.

3. The method according to claim 1, wherein said accessory mark includes type information of said control information.

4. The method according to claim 1, further comprising the step of: filtering each control information version of said interactive application.

5. The method according to claim 1, further comprising the step of: writing said digital TV program' s transport stream into a storage media.

6. The method according to claim 1, further comprising the step of: writing said accessory mark into a mark description file.

7. A method for trick playing a transport stream of a digital TV program, operable to trick play the transport stream by switching from a current point to a next play point, comprising steps of: reading an accessory mark used to mark whether there is version change of an interactive application' s control information in the transport stream; determining whether there is version change of said control information from said current point to said next play point, according to said accessory mark; and processing said interactive application according to the control information version at the position of an accessory mark previous to said next play point if there is a change.

8. The method according to claim 7, further comprising the step of: obtaining position information of said current point and said next play point in the transport stream.

9. The method according to claim 7, further comprising the step of: receiving an input from a user, the input including a request for trick playing said transport stream in a particular mode.

10. The method according to claim 7, wherein said accessory mark includes corresponding position information of the transport stream when there is a version change of said control information.

11. The method according to claim 7, wherein said accessory mark includes type information of said control information.

12. A recording apparatus for recording a transport stream of an interactive digital TV program, comprising: determining means, for determining whether there is version change of an interactive application' s control information in said transport stream; and generating means, for generating an accessory mark used to mark said version change.

13. The apparatus according to claim 12, wherein said accessory mark includes corresponding position information of the transport stream when there is a version change of said control information.

14. The apparatus according to claim 12, wherein said accessory mark includes type information of said control information.

15. The apparatus according to claim 12, further comprising a storage media for storing said accessory mark.

16. The apparatus according to claim 14, further comprising program recording means, for writing said digital TV program's transport stream into said storage media.

17. A playing apparatus for trick playing a transport stream by switching from a current point to a next play point, comprising: reading means, for reading an accessory mark used to mark whether there is version change of an interactive application's control information in the transport stream; determining means, for determining whether there is version change of said control information from said current point to said next play point, according to said accessory mark; and processing means, for processing said interactive application according to the control information version at the position of an accessory mark previous to said next play point if there is a change.

18. The apparatus according to claim 17, wherein said accessory mark includes corresponding position information of the transport stream when there is a version change of said control information.

19. The apparatus according to claim 17, wherein said accessory mark includes type information of said control information.

20. The apparatus according to claim 17, further comprising location positioning means, for obtaining position information of said current point and said next play point in the transport stream.

21. The apparatus according to claim 17, further comprising a storage media in which there is a mark description file for storing said accessory mark information.