MXPA06002523A - Auxiliary information processing system - Google Patents

Abstract

A system and method is provided for switching between various VBI encoding standards of an MPEG2 digital television signal in order to obtain correct and virtually seamless VBI data. The decoded VBI data is then re-encoded into an NTSC video signal (24) for presentation to an NTSC display (26). The system and method utilizes valid user data (52) as defined in the MPEG2 video system specifications and the ATSC standard for switching among various VBI data encoding formats. In this manner, it is possible to reduce un-wanted switching and eliminate the loss of data for un-wanted switching.

Description

AUXILIARY INFORMATION PROCESSING SYSTEM CROSS REFERENCE WITH RELATED APPLICATIONS This United States non-provisional patent application claims the benefit and / or priority of Provisional Patent Application Serial No. 60 / 500,443, filed on September 5, 2003, and entitled "AUXILIARY INFORMATION PROCESSING SYSTEM "(AUXILIARY INFORMATION PROCESSING SYSTEM", which is incorporated herein in its entirety as a reference.

FIELD OF THE INVENTION The present invention relates to a method and apparatus for processing digital television signals and more in particular to a method and apparatus for processing auxiliary information in digital television signals.

BACKGROUND OF THE INVENTION Many television signals include data or auxiliary information, that is, information or data different from video programs or audio program information. Examples of auxiliary information include sub-title data in the United States, program guide information, program sub-titles, emergency messages, video sampled in non-real time, and the like. This information or auxiliary data may be collectively called auxiliary information.

In analog television signals, auxiliary information is typically included in the signal during the vertical blocking interval (VBI) and therefore, the auxiliary information may also be called "VBI data" or "VBI services" (collectively "data"). VBI "). The term VBI data is used although in other types of television signals, such as digital television signals, VBI data is provided through a particular stream of digital data packets better than in the vertical blocking interval or in a range of particular time of the television signal. With respect to certain television signals, such as digital television signals, it is necessary to decode the VBI data from the digital bit stream and then re-encode the VBI data for presentation in a similar video output. With respect to digital television signals using MPEG-2 coding, it may be necessary to decode the VB1 data of the MPEG-2 user data (ie, the MPEG-2 compliant bitstream) between different data standards VBI (for example, ATSC, SCTE 20 and SCTE 21) and then re-encode the VBI data as NTSC video for its output and / or use by the video deployment and / or the NTSC component. The current digital television signal receivers only have the ability to decode a VBI data type of an MPEG-2 signal. Therefore, it will be evident that what is needed is a digital television signal receiver that operates to decode the VBl data in a MPEG2 compliant bitstream encoded by one of the plural VBl data standards. Also, it will be apparent from the foregoing, that what is needed is a digital television signal receiver that operates to decode VBl data in a MPEG2 compliant stream encoded by one of the plurality of VBl data standards and re-encode VBl data decoded in an NTSC signal. Also, it is evident from the foregoing that what is needed is a digital television signal receiver that operates to decode the VBl data in an MPEG2 compliant bit stream encoded with any of the plurality of VBl data standards and -code the encoded VBl data in an NTSC signal without loss of VBl data. These needs and others are met with the application of the principles of the present invention and / or as they are incorporated in one or several methods, forms and / or systems, such as those shown and / or described herein.

BRIEF DESCRIPTION OF THE INVENTION A system and method for switching between several VBl coding standards of an MPEG-2 digital television signal obtains the VBl data virtually uninterrupted and correct. The decoded VBl data is then re-encoded into an NTSC video signal for presentation in an NTSC display. The system and method use valid user data defined in the MPEG-2 video system specifications and the ATSC standard to switch between various VBl data encoding formats. In one form, the present invention provides a method for decoding VBl data from an MPEG-2 television signal. The method includes the steps of (a) receiving an MPEG-2 television signal; (b) decoding the MPEG-2 television signal to obtain a video signal; (c) determine if there are valid user data in the obtained video signal; (d) determining whether the valid user data exists in the obtained video signal, a value of the user's valid data, and (e) decoding the VBl data of the video signal in accordance with one of a plurality of encoding formats. of VBl data as determined by the value of the user's valid data. In another form, the present invention provides a method for decoding VBl data from an MPEG-2 television signal. The method includes the steps of: (a) receiving an MPEG-2 television signal; (b) obtaining the video data of the MPEG-2 television signal; (c) determining if there are valid user data in the obtained video data; (d) determining, if there is valid user data in the obtained video data, the VBl data coding format of the MPEG-2 television signal, and (e) decoding the existing VBl data in the video data of conformity with the determined VBl data coding format. In another form, the present invention provides a receiver of digital television signal. The digital television signal receiver includes an MPEG-2 decoder that operates to obtain video data of a received MPEG-2 television signal, a VBl data extractor connected to the MPEG-2 decoder and operating to obtain the VBl data. of the obtained video data; and a data determiner VB1 connected to the data extractor VB1 and operating to determine whether the obtained VB1 data includes valid user data, a data encoding determinant VB1 connected to the VB1 data determiner and operating to determine the format VBl coding of the VBl data and a VBl data decoder connected to the VBl data coding determiner and operating to decode the VBl data in accordance with the determined VBl coding format.

BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned and other characteristics and objects of this invention and the way to achieve them will be evident from the invention and will be better understood when referring to the following description of an embodiment of the invention taken together with the drawings companions, in which: Figure 1 is a simplified block diagram of an exemplary digital television signal receiver in accordance with the principles of the present invention. Figure 2 is a more detailed block diagram of an exemplary digital television signal receiver in accordance with the principles of the present invention. Figure 3 is a flow chart of an exemplary form for determining the VB1 coding standard in accordance with the principles of the present invention. Figure 4 is a flowchart of a portion in an exemplary manner for decoding VBl data in accordance with the principles of the present invention. Figure 5 is a flow chart of another portion of the exemplary form for decoding VBl data in accordance with the principles of the present invention. The corresponding reference numbers indicate corresponding parts through the different views. Although the drawings represent embodiments of the invention, the drawings are not necessarily to scale and certain features may be extended in order to illustrate and explain the present invention. The examples set forth herein illustrate one embodiment of the invention, in one form and such examples are not to be construed as limiting the scope of the invention in any way.

DETAILED DESCRIPTION OF THE INVENTION The embodiment described herein is not intended to be exhaustive or to limit the invention to the precise form described, so that those skilled in the art can utilize these teachings. Figure 1 illustrates a block diagram of a system, so general signal with the 10, which receives a digital television signal, processes the digital television signal and emits an analog video signal, all this in accordance with the principles of the invention. In particular, the system 10 operates, is configured and / or adapted to receive a digital television signal, process the digital television signal in the manner described herein and emit (provide) at least one NTSC video signal. The system 10 is characterized by a digital television signal receiver 12. The digital television signal receiver (DTSR) 12 is representative of a type of television signal receiver, such as a television, VCR, DVD, a transcoder, a DVR or its like, using digital television signals. While not described, the digital television signal receiver 12 may also receive, process and / or use analog television signals in a manner known in the art. The digital television signal receiver 12 includes an input 14 configured to receive a digital television signal 16. The digital television signal 16 can be provided by several sources such as cable, satellite, terrestrial or through another component. The digital television signal 16 can be in the ATSC format, the SCTE 20 format, the SCTE 21 format, the DVB format (DVB-S, DVB-T, DVB-C) and any other format. As such, the digital television signal 16 is in the MPEG-2 compression format, but may be in other digital compression formats. Also, the digital television signal 16 may include VBl information or formatted data according to the previous format schemes. While not described, digital television signal 16 also includes audio information such as in the AC-3 format (for ATSC signals) and the MPEG-2 format (for DVB signals). The digital television signal receiver 12 includes a memory 18 which may be one of or in various ways known in the art of memories such as RAM, ROM, EEPROM, flash memory or the like. In the same way, although not shown, the memory 18 may be complemented or take the form of a data storage medium such as hard disks and their like, all collectively called memory. The memory 18 stores program instructions, firmware, software or its like 20 (collectively, program instructions). The program instructions 20 are used by the television signal receiver 12 and / or by its different components for the operation of the different characteristics, functions, capacities and / or their like of the television signal receiver 12, including the characteristics and / or functions described herein in accordance with the principles of the present invention. The digital television signal receiver 12 also includes a processor, processor or processing circuitry and / or logic indicated with the number 22, and collectively called circuitry / logic. As such, the processing circuitry / logic 22 can be incorporated as one or more integrated circuits (chips) with or without additional circuitry and / or logic. The Different components of the processing circuitry / logic 22 may be under partial, or total, control of the program instructions. The processing circuitry / logic 22 operates, is configured and / or adapted to process the incoming digital television signal 16. In particular, the circuitry / logic 22 operates, is configured and / or adapted to receive and decompress / decode the MPEG-2 bitstream (or other digital compression / coding scheme) of the incoming digital television signal 16, separates or analyzes the data / audio and video information from it, and separates or analyzes any auxiliary information (VBl) in it. In addition, the processing logic / circuitry 22 operates, is configured and / or adapted to process the audio and video information in order to provide an appropriate audio output and to provide an appropriate video output. With respect to this, the processing logic / circuitry 22 operates, is configured and / or adapted to encode the video information as NTSC video in order to provide an NTSC video signal 26 in the video output 24 of the receiver 12 of digital television. It should be appreciated that the digital television signal receiver 12 also includes other components that are not shown and / or described here, but which are known in the art for practical use and / or operation thereof. Without limiting or being exhaustive, the components include remote control devices, channel tuning devices and / or their like. In accordance with the principles of the present invention, the circuitry / logic 22 processing also operates, is configured and / or adapted to switch between various data / information decoding algorithms VBl for different VBl coding standards (eg ATSC, SCTE 20, SCTE 21) in order to obtaining and decoding the VBl data appropriately within the digital television signal. In this way, none or almost none of the VBl data is lost in the determination of the data encoding standard VBl used in the digital television signal 16 for the VB1 decoding. This allows the digital television receiver 12 to correctly decode the VBl data and then re-encode the VBl data into an NTSC video signal 26. Briefly, the processing circuitry / logic 22 uses or looks for an encoding parameter for the valid user data, syntax or semantics of the VB1 coding standard (i.e., valid user data as a valid user syntax) of the user. conformance with the VBl data coding standard to determine the VBl data decoding standard. In this way, once the data is decoded, the processing logic / circuitry 22 adds the VBl data to the NTSC video signal 26 at the video output 24. It should be appreciated that the present invention operates for different VBl coding standards, but for exemplary purposes of the present invention will be described with respect to the three most important VBl coding standards for digital television signals, namely ATSC (Advanced Television Systems Committee), SCTE 20 (Society of Cable Telecommunications Engineers-Standard Methods for Carriage of Closed Captions and Non-Real Time Sampled Video) and SCTE 21 (Society of Cable Telecommunications Engineers-Standard Methods for Carriage of NTSC VBl Data in Digital Cable Transport Streams). The ATSC and STCE 21 are similar except that STCE 21 has extensions for new codes 4 and 5 type of user data that are for additional data and new luma data. Because of this, it is possible to discriminate SCTE 21 from ATSC with the use of user data type codes (i.e. to determine the presence of a particular VBl data syntax). However, with SCTE 20 and SCTE 21, there is a totally different structure. Therefore, it is necessary to have a way to determine and decode SCTE 20 and SCTE 21. It is desirable to decide the data format that needs to be decoded and displayed on the screen and re-encoded for the NTSC video output, even when both they are decoded simultaneously, since it may be inconvenient to display both data formats at the same time on the screen. It is also not possible to encode two different VBl data for an NTSC output. This is why it is necessary to decide the format that needs to be decoded, encoded and displayed. As described herein, the present system provides a way to decide the current decoding format to be used among multiple data formats. In Figure 2, the functional portions of the receiver 12 of Digital television system 10 are shown for switching the decoding data format from among several exemplary VB1 coding formats for MPEG-2 digital television signals (e.g., ATSC, SCTE 20 and SCTE 21). In particular, Figure 2 illustrates a digital television signal receiver 12 with the functional blocks necessary to realize the principles of the present invention. Program instructions 20 are included to indicate that several components and / or processing is at least partial, if not total, control of firmware, software or the like. The digital television signal receiver 12 receives the digital television signal 16 (DTV) at the input 14 and proceeds to decode the DTV MPEG-2 signal through an MPEG-2 decoder 30. A VBl data extractor 32 is provided to extract the VBl data from the MPEG-2 signal that operates to extract the VBl data from the MPEG-2 signal. This is achieved when only the valid user data defined by the ATSC standard is detected. A VBl data coding standard determiner 34 is provided, which operates to determine the VBl data coding standard for the extracted VBl data. While these three formats are described (ie, ATSC, SCTE 20 and SCTE 21) it should be appreciated that other formats can be supported. A VB1 data decoder 26 is provided, which operates to decode the VBl data extracted from the MPEG-2 signal in accordance with the determined VBl data coding standard.

Also, a NTSC VB1 encoder 38 is provided which operates to encode the decoded VBl data of the MPEG-2 signal in an NTSC format. The NTSC encoded VBl data is then inserted into the NTSC video signal 26. The NTSC video signal 26 is fed into the output 24 of the digital television signal receiver 12. Referring now to Figure 3, there is illustrated a flow chart of an exemplary form of operation, as generally indicated, with 50 of the present television. The operation of the system 10 begins with the detection of valid user data in a current 52 of MPEG-2 video. In this way, the operation illustrated in Figure 1 will start every time the system detects valid user data while decoding the MPEG-2 video. In one form, the valid user data is detected when the user_code_starts_data defined in MPEG-2 and / or in the ATSC standard (a user data parameter) is received. Each time 52 valid user data are detected, the system begins to decode with the use of the current mode to detect valid data and the decoding process is presented in Figures 3, 4 and 5. Once 52 are detected Valid user data, the system decides the decoding mode to which the system is set. When the current mode is not set to NONE (ie, the decoding mode of the DTSR is set to one of the three decoding modes), then the determination in step 54 is NO (N) and the routine 66 of decoding This ends on program flow of Figure 3. However, when it is determined that the current mode is NONE (ie, the decoding mode of the DTSR is set to one of the three decoding modes), then the system decides the decoding mode and then it will assign a selected value to the current mode when the valid data mode is detected. In this way, when the determination step 54 is YES (Y), the system proceeds to decide the decoding mode. When a valid decoding mode is found, the system continues to decode until the system fails to decode for a predetermined time determined by the function of the synchronizer identified as WaitTimer. The WaitTimer will be re-started every time valid VBl data is detected from the user's data. This means that it will be necessary to wait for switching to a new decoding mode after obtaining valid data with the current mode. Therefore, an alternative mode may involve starting with the current mode as NONE (default mode) when operation 50 of the system begins. In that case, the system decides the current mode from the beginning. With reference again to the system 50, the system then determines, in step 56, whether the identification parameter ATSC (ATSC_id) is received after the user_code_starts_data (another user data parameter) is obtained. When the ATSC_id has been received (ie, Y for itself) then the current mode can be ATSC or SCTE 21. This data is stored for processing during the decoding routine 66. The program flow then advances to the decoding routine 66. Then, the flow 50 of the current program ends at 68. When the ATSC_id has not been received (ie, N for no) the program flow proceeds to step 58. In step 58, the system determines whether the code 0x03 type User data (another user data parameter) has been received. When the user data type 0x03 has not been received (ie, N for NO), then the system in step 60 sets the current mode in SCTE 20. When the user data type 0x03 has been received (i.e. , And for itself), then the system in step 64 sets the current mode to NONE. After the system decoding mode has been set, the program advances to the decoding routine 66 and then terminates its routine 68. The decoding routine 66 is illustrated in Figure 4. The decoding routine 66 starts with step 70 of the MPEG-2 VBl data decoding routine. After, the system determines, in step 72, whether the current mode has been set in ATSC or in SCTE 21. When the current mode is set in ATSC or in SCTE 21 (ie, Y for yes), then the routine is requested 74 of ATSC or SCTE 21 decoding. This will be described along with Figure 5 below. Then, routine 66 ends at 88. When the current mode in step 72 is not ATSC or SCTE 21 (ie, N for not), then the program flow proceeds to step 76, where it is determined whether the mode Current is adjusted in SCTE 20.

When this is not the case (N for not), the routine 66 of the system ends and the system starts again to determine the reception of valid user data. When it is yes (Y), then the program flow proceeds to step 78, where it is determined whether the user data type 0x03 has been received. When the user data type 0x03 has not been received (ie, N for not), the program flow proceeds to step 82, where the WaitTimer setting is checked to determine if it should be set to 0. When the WaitTimer it is not set to 0 (ie, N to no), then the program flow ends at 88. when the WaitTimer is set to 0, (ie, Y to yes), then the system sets the current mode to NONE , step 84, and this routine ends at 88. When the user data type 0x03 is received in step 78, then the system checks to determine if the next seven bits received are "1000 000". When it is not like this (N), then the WaitTimer is set to 0 (ie, Y for itself) then the system sets the current mode to NONE, in step 84 and the routine ends in 88. When the next seven bits received they are "1000 000" this means that the coding format of SCTE 21. Thus, in step 86, the VBl data is decoded with the use of the SCTE21 decoding format. The decoded data is then sent to the NTSC encoder and the WaitTimer is set to lNT_VALOR. Then, the program 66 ends at 88. With reference to Figure 5, the ATSC or SCTE 21 decoding routine 74 is illustrated. The decoding routine 74 ATSC or SCTE 21 starts with step 90 that starts or starts the routine. Then, it is determined if the ATSC_id has been received. When not (N), the program flow proceeds to step 98 where the system then determines whether the WaitTimer is set to 0. When not (N), then routine 74 ends. When yes (Y), then current mode is set to NONE, step 100, and routine 74 ends at 114. When the ATSC_id (Y) has been received, then the system in step 94 determines whether the data type code of the user is 3, 4 or 5. When not (N), the program flow proceeds to step 98 where the system then determines whether WaitTimer is set to 0. When the WaitTimer does not (N) is set to 0 then the routine 74 ends at 114. When the WaitTimer is set to 0 (ie, if Y), then the current mode is set to NONE, in step 100 and routine 74 ends at 114. When the ATSC_ld is set to 3, 4 or 5 (Y), then the system determines in step 96 if the code of the user's data type is 3. When the user's data code type is 3, then the ATSC encoding format to be used and the flow of the program proceeds to step 106. In step 106, the VBl data is decoded with the use of the ATSC decoding format and the WaitTimer is adjusted in INT_VALOR. Then the decoding continues and the routine ends at 114. When the user data type code is not 3 (N), then the system proceeds to step 102, where SCTE21 is set as the current mode and the WaitTimer and set to INT_VALOR. Then, the system determines in step 104, if the user's data type code is = 4. When not (N); the system proceeds to step 110. In step 110, it is determined if the user's data type code is 5. When not (N), routine 74 ends 114. When yes (Y), then PAM luma data is they decode to 112. However, when in step 104, it is determined that the user's data type code is 4 (Y), then the data of the EIA standard 608 is decoded. Another alternate modality for switching the current decoding mode involves switching every time there is valid data the user stops the valid VBl data can not be obtained. As a result, it is possible to detect a new format as valid user data and VBl data and therefore, it is possible to avoid unnecessary switching while there is no data for a period of time. While this invention has been described as a preferred design, the present invention can be modified within the spirit and scope of the description. Therefore, this application is intended to cover variations, uses and adaptations to cover such sections with the use of its general principles. Also, this application is intended to encompass such sections of the present invention which fall within the known or customary practice of the art to which the invention pertains and which fall within the limits of the appended claims.

Claims (12)

1. A method for decoding VBl data of an MPEG-2 television signal characterized in that it comprises the steps of: receiving an MPEG-2 television signal; decode the MPEG-2 television signal to obtain a video signal; determine if there are valid user data in the obtained video signal; determine, if the valid data of the user exist in the obtained video signal, a value of the valid data of the user; and decoding the VBl data of the video signal in accordance with one of the plurality of data encoding formats VBl as determined by the value of the user's valid data.

The method according to claim 1, characterized in that the plurality of coding formats comprises ATSC, SCTE 20 and SCTE 21.

3. The method according to claim 1, characterized in that the user's valid data comprises a code of start.

4. The method according to claim 3, characterized in that the start code comprises 0x000001B2.

5. The method according to claim 1, characterized in that it further comprises the step of: encoding the decoded VBl data of the video signal into an encoded NTSC signal from the obtained video data.

The method according to claim 1, characterized in that it further comprises the step of: continuing to decode the VBl data of the video signal until the system fails to decode for a predetermined period of time.

7. A method for decoding VBl data of an MPEG-2 television signal comprising the steps of: receiving an MPEG-2 television signal; obtain video data from the MPEG-2 television signal; determine if there are valid user data in the obtained video data; determining whether there is valid user data in the obtained video data, a VBl data encoding format of the MPEG-2 television signal; and decoding the existing VBl data in the video data in accordance with the determined VBl data coding format.

The method according to claim 7, characterized in that it further comprises the step of: inserting the decoded VBl data into an encoded NTSC video signal of the obtained video data.

The method according to claim 7, characterized in that the plurality of encoding formats comprise ATSC; SCTE 20 and SCTE 21.

10. The method according to claim 7, characterized in that the valid data of the user comprises a start code. The method according to claim 10, characterized in that the start code comprises 0x000001B2. The method according to claim 7, characterized in that it further comprises the step of: continuing to decode the VBl data of the video signal until the system fails to decode for a predetermined period of time.