Abstract:
A processing method and a processing apparatus for a digital television are provided. A processing apparatus for a digital television (DTV) to process a DTV stream, comprising: a demultiplexing unit for retrieving a service information from the DTV stream; a memory coupled to the demultiplexing unit for storing the service information; a first processor coupled to the memory for assigning a task by sending a command according to the service information; a second processor coupled to the memory for processing the task according the command; a communication unit coupled to the first processor and the second processor, for receiving the command from the first processor and sending the command to the second processor; and at least one function module coupled to the first processor and the second processor, respectively, controlled by the first processor or the second processor, to process the service information.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to Taiwan Patent Application No. 096140564 filed on 29 Oct. 2007, the contents of which are incorporated herein by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a dual-processor apparatus and a processing method for a digital television (DTV). 
         [0004]    2. Descriptions of the Related Art 
         [0005]    Digital televisions (DTVs) are expected to become the focus in the development of the next generation of household information appliances and also an important gateway for accessing the Internet from home. 
         [0006]    DTVs, which are apparatuses that receive DTV signals, are configured to receive audio/video data transmitted by a TV station. The audio/video data is processed (e.g., encoded, compressed and etc.) digitally in the television station at the central office and then broadcasted, multicasted or unicasted to a DTV terminal. When the digital signals are received, the DTV terminal decompresses and decodes, and then display on a TV screen. Here, “digital” indicates that the TV signals are encoded in a digital manner. Because this can improve the immunity against the interference and bandwidth can be exerted effectively. Industry standards for this kind of digital encoding and decoding for DTV are mainly published by ITU-T and ISO/IEC standard organization. For example, H.261, H.262 and H.263 standards are published by the ITU-T. The compression standards published by the ISO/SEC are categorized as: JPEG, JPIG and JPEG2000 for still picture compression; MPEG-1 (Moving Picture Experts Group) and MPEG-2 for moving picture compression and encoding; MPEG-4 for multimedia encoding/decoding and compression based on audio/video media objects, MPEG-7 (“multimedia content description interface”) and MPEG-21 (“Multimedia Framework”). Furthermore, relevant standards also include the H.264 standards proposed by the JVT Organization. Among these standards, the MPEG series has become the most popular international standards for multimedia technologies, and has exerted a great and far-reaching influence on the development of DTVs, audio/video consumer electronics and multimedia communication industries. With the above digital signal compression technologies, it is possible for DTVs to transmit High-Definition TV (HDTV) signals with a much higher definition and audio quality than traditional analog TVs. It is also possible to transmit Enhanced Definition TV (EDTV) and Standard Definition TV (SDTV) programs simultaneously in a channel. The DTV service providers may transmit a large amount of information related to TV programs or other services via data bitstreams while broadcasting TV programs. Therefore, a DTV system is much better than a traditional analog TV system in terms of audio/video performance and compatibility with computer information products. 
         [0007]    A typical DTV uses a single Complex Instruction Set Computer (CISC) processor (e.g., a 32-bit MIPS/ARM processor) with a high computing capacity to process video and audio streams related to DTV signals, and also to undertake a large amount of calculations with respect to particular information. Accordingly, a complex management and processing mechanism or operating system is needed in a DTV of this structure to assign and manage the software and hardware resources of the DTV, as well as to schedule and manage various operations. However, the use of a complex management and processing mechanism or operating system will not only increase the need for a stronger DTV hardware and added software and hardware costs, but also decrease the processing efficiency and timeliness. 
         [0008]    Accordingly, a new DTV structure is proposed in this invention to solve these problems. 
       SUMMARY OF THE INVENTION 
       [0009]    One objective of this invention is to provide a processing apparatus for a digital television (DTV). A processing apparatus for a digital television (DTV) to process a DTV stream, comprising: a demultiplexing unit for retrieving a service information from the DTV stream; a memory coupled to the demultiplexing unit for storing the service information; a first processor coupled to the memory for assigning a task by sending a command according to the service information; a second processor coupled to the memory for processing the task according the command; a communication unit coupled to the first processor and the second processor, for receiving the command from the first processor and sending the command to the second processor; and at least one function module coupled to the first processor and the second processor, respectively, controlled by the first processor or the second processor, to process the service information. 
         [0010]    Another objective of this invention is to provide a processing method for a DTV. A processing method for a DTV having a first processor, a second processor and a communication unit to process a DTV stream, the method comprising the following steps of; retrieving and storing a service information from the DTV stream; assigning a task according to the service information and sending a command to the communication by the first processor; receiving the command and sending it to the second processor by the communication unit; and processing the task by the second processor. 
         [0011]    A further objective of this invention is to provide a processing method for a DTV. A processing method for a DTV having a first processor, a second processor and a communication unit to decompress vector font data, the method comprising the following steps of: receiving a service information for decompressing the vector font data; loading vector font data and sending a command to the communication unit by the first processor; receiving the command and sending it to the second processor by the communication unit; and accessing the vector font data and decompressing the vector font data by the second processor. 
         [0012]    By accomplishing the above objectives, this invention is capable of using at least two processors for processing or decoding a DTV, rather than using only one CISC processor for processing like those in conventional DTVs. Therefore, DTV processing can be accomplished by using different processors in combination, for example, an 8-bit 8051 microprocessor in combination with a 32-bit MIPS/ARM processor. 
         [0013]    The detailed technology and preferred embodiments implemented for the subject invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  illustrates the system structure of this invention; 
           [0015]      FIG. 2  is the data format in a message register of this invention; 
           [0016]      FIG. 3  is a flow diagram illustrating a method for processing the DTV information of this invention; 
           [0017]      FIG. 4  is a flow diagram illustrating a method for processing the DTV vector font of this invention; and 
           [0018]      FIG. 5  is a flow diagram illustrating another method for processing the DTV information of this invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]    The system structure of a digital television (DTV) processing apparatus  1  according to this invention is depicted in  FIG. 1 . The DTV processing apparatus  1  comprises a tuner  11 , a demodulator  13  and a processing apparatus  15  for processing the DTV data stream. The processing apparatus  1  receives DTV broadcasting signals  10 . The DTV broadcasting signals  10  may comply with the Digital Video Broadcasting-Terrestrial (DVB-T) standard, the Digital Video Broadcasting-Satellite (DVB-S) standard, or the Digital Video Broadcasting-Cable (DVB-C) standard established by the Digital Video Broadcasting (DVB) Organization; the Digital Television Standard established by the Advanced Television System Committee (ATSC); or relevant DTV standards established by other standardization organizations. When processed by the demodulator  13 , the DTV broadcasting signals  10  are be transferred to a DTV data stream  12 , which is then received and processed by the processing apparatus  15 . 
         [0020]    The processing apparatus  15  comprises a demultiplexing unit  151 , a memory  153 , a first processor  155 , a second processor  157 , a communication unit  159 , and a plurality of function modules such as an image processing module  161  and an audio processing module  163 . The demultiplexing unit  151  further comprises a demultiplexer  1511  and a service information processor  1513 . The demultiplexer  1511  is configured to receive the DTV data stream  12  and process it into a video stream  152 , an audio stream  154  and at least one data stream  150 . After receiving the data stream  150 , the service information processor  1513  retrieves from the data stream  150  at least one piece of DTV service information  156 , for example, information related to DTV services such as an electronic program guide (EPG), subtitles, and MHEG-5 information. The DTV service information  156  is then stored into the memory  153 . 
         [0021]    The first processor  155  and the second processor  157  exchange information via the memory  153  and the communication unit  159 , and both are able to control a plurality of function modules such as the image processing module  161  and the audio processing module  163 . In the preferred embodiment, the first processor  155  may be a processor with a low processing capacity, for example (but not limited to) a 8-bit processor, which is primarily intended to process the information related to on-screen display (OSD), manage system resources and task assignment, and retrieve DTV service information. Moreover, the first processor  155  can receive a user control command  164  to control the demultiplexing unit  151  to receive DTV data streams  12  and retrieve the service information  156 . On the other hand, the second processor  157  may be a processor with a high processing capacity, for example (but not limited to) a 32-bit processor, which is primarily intended to process the information in the DTV data stream  12  that necessitates complex computations, for example, MEHG-5 and JAVA multimedia information. When receiving a message to process such information involving complex computations, the first processor  155  calls the second processor  157  via the communication unit  159  to access the information from the memory  153  and process it. The second processor  157  may also be provided with an ability to control the demultiplexing unit  151 . On the other hand, if the information processed by the second processor  157  needs to be responded to the first processor  155  or processed furthermore by the first processor  155 , the second processor  157  calls the first processor  155  via the communication unit  159 . And the second processor  157  stores the processed information into the memory  153 . The communication unit  159 , which is an interrupting processing unit, an information register or a combination thereof, is configured to transmit commands between the first processor  155  and the second processor  157 . In the preferred embodiment, an interrupting processing unit of the communication unit  159  may provide bi-directional interrupting commands. The message register comprises two groups of 16-byte registers: one is used by the first processor to call the second processor, while the other is used by the second processor to call the first processor. A data format of the register is shown in  FIG. 2 . Byte  0  to Byte  2  are used to label different kinds of calling messages such as the processing of the vector font and also processing the MHEG-5 information or the like. Byte  3  is used to indicate the content length of the calling message, Byte  4  to Byte  13  are used for the content of the calling information, while the Byte  14  to Byte  15  are used as status bytes to record the current processing status. When the first processor  155  needs to send a calling message or a command to the second processor  157 , the content of the calling message is filled into the register and sends an interrupting command via the interrupting unit to call the second processor  157 . When the interrupting command is received, the second processor  157  reads the register and operates according to the content stored therein. 
         [0022]    The operation of a DTV, as well as the communications and division of work between the first processor  155  and the second processor  157  will now be further described with reference to two methods for processing particular DTV information. When information to be processed is vector font information, the first processor  155  calls the second processor  157  via the communication unit  159  to access the vector font information stored in the memory  153 . Subsequently, the second processor  157  decompresses the vector font information into bitmap information, and then calls the first processor  155  via the communication unit  159  to inform the processing result of the vector font information. 
         [0023]    Alternatively, when the processed information is an MHEG-5 (Multimedia and Hypermedia Experts Group-5) message, the first processor  155  calls the second processor  157  via the communication unit  159  to process this MHEG-5 message. Then the second processor gains control of the demultiplexing unit  151 , analyzes the MHEG-5 message, and retrieves the IFrame data therefrom to be stored into the memory  153 . Subsequently, the second processor  157  calls the first processor  155  directly or via the communication unit  159  to control the image processing module  161  to access the IFrame data from the memory  153  and decompress the IFrame data into the picture data. 
         [0024]    Furthermore, the first processor  155  and the second processor  157  can further control the function modules (e.g., the image processing module  161  and the audio processing module  163 ) to process particular information, such as the video stream  152  and the audio stream  154  described above. The function modules  161 ,  163  of the processing apparatus usually have a programmable control unit (i.e., an image processing controller  1611  and an audio processing controller  1631 ) and a particular function processing unit (i.e., an image decoder  1613  and an audio decoder  1633 ). The programmable control unit has a control program (not shown) stored therein, which can be reprogrammed according to the DTV standards of different countries to enhance its expandability and fault tolerance. More specifically, by using the programmable control unit and the particular function processing unit in combination, the processing apparatus  15  can process the various particular information of the DTV data stream  12  more promptly. 
         [0025]    In particular, according to the video control command  160  transmitted by the first processor  155  or the second processor  157  and a control program stored in the image processing controller  1611 , the image processing controller  1611  can control the image decoder  1613  to decode the video stream  152  or other image information, for example, an MEHG-5 IFrame. 
         [0026]    Likewise, according to the audio control command  162  transmitted by the first processor  155  or the second processor  157  and a control program stored in the audio processing controller  1631 , the audio processing controller  1631  can control the audio decoder  1633  to decode the audio stream  154  or other audio information. 
         [0027]    This invention further provides a processing method for a DTV, which is applicable to the processing apparatus  15  described above. 
         [0028]    In more detail, the processing method for a DTV is implemented by an application controlling the various modules of the processing apparatus  15 , and a corresponding flow diagram thereof is depicted in  FIG. 3 . 
         [0029]    Initially in step  301 , the DTV service information is received. Then in step  303 , the type of DTV service information is checked by a first processor  155 . Finally in step  505 , the DTV service information is processed by a first processor  155  and/or a second processor  157  directly controlling the function module. 
         [0030]    To illustrate this invention more clearly, a further description will now be made with reference to the two kinds of exemplary particular DTV information. This invention provides a processing method for a DTV vector font, which is applicable to the processing apparatus  15  described above. A corresponding flow diagram of this processing method is depicted in  FIG. 4 . 
         [0031]    Initially in step  401 , service information for processing the vector font information is received by the first processor  155 , while vector font information is loaded into a memory  153 . Then in step  403 , the vector font data is read by the first processor  155  that calls the second processor  157  through the communication unit  159 . Next in step  405 , the vector font is read from the memory  153  by the second processor  157  which calls the first processor  155  once the reading process is completed. Subsequently in step  407 , the first processor  155  calls the second processor  157  to decompressed the vector font data through the communication unit  159 . Finally in step  409 , the vector font data is decompressed into Bitmap information by the second processor  157 . 
         [0032]    This invention further provides another processing method for a DTV, which is applicable to the processing apparatus  15  described above. A corresponding flow diagram of this processing method is depicted in  FIG. 5 . 
         [0033]    Initially in step  501 , a DTV data stream is received. Then in step  503 , the DTV data stream is detected by a first processor  155  to determine if an MHEG-5 message is incoming. Subsequently, the MHEG-5 message is processed by the first processor  155  calling a second processor  157  in step  505 . Next in step  507 , the MHEG-5 message is processed to retrieve IFrame data by the second processor  157 . Then in step  509 , the IFrame data is stored in the memory  153 . Finally in step  511 , the IFrame data is decompressed into picture data by an image processing module  161  under control of the second processor  157  or the first processor  155 . 
         [0034]    It follows from the above description that this invention uses at least two processors to process or decode DTV data streams. That is, the DTV data streams are processed by a combination of different processors, for example, an 8-bit 8051 microprocessor in combination with a 32-bit processor. In a structure where a plurality of processors cooperates to process the information can decrease the complexity in software and hardware of a DTV, thus increasing the processing efficiency and timeliness thereof. Furthermore, this may also prevent additional costs and time required to develop a CISC processor applicable to a DTV. 
         [0035]    The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.