The displaying device according to the embodiment of the invention has changed to be different from the method of sequentially representing and displaying the characters from left to right and from top to bottom, but to analyze and classify the received subtitle data and to rearrange the order of all the characters of the subtitle data so that the graphic engine chip can represent all the characters according to the new order.
After obtaining the subtitle data, the processing unit 110 analyzes all the characters of the subtitle data to obtain locations of the characters appearing on the frame. Next, the processing unit 110 creates a character link list for recording the locations of all the characters of the subtitle data appearing on the frame.
Then, the processing unit 110 calls an application program interface, which rearranges nodes in the character link list to adjust the order of displaying all the characters in the subtitle data.
The processing unit 110 stores the bitmap raw data of the characters from the system memory to the off-screen memory 120 according to the character link list. The graphic engine chip 130 generates and represents the characters in the on-screen memory 122, and displays the characters on the display unit 140 according to the bitmap raw data of the character of the off-screen memory 120 in conjunction with a color extension or conversion command.
Next, in step 220, the processing unit 110 sequentially analyzes the first character and the second character and creates the character link list to record the locations of the first character and the second character on the frame. The first character appears at one or more than one location on the frame, such as a first location on the frame, and the second character appears at one or more than one location on the frame, such as a second location on the frame.
In step 230, the processing unit 110 calls the application program interface to rearrange the character link list to adjust the order of displaying the first character and the second character.
In step 240, a character, such as the first character, is taken out from the character link list so that the bitmap raw data of the character is loaded from the system memory into the off-screen memory 120. In addition, the commands for operating the graphic engine chip 130 are stored in a graphic register according to the attribute of the first character, such as the location and the color.
In step 250, the graphic engine chip 130 generates a first representing character according to the bitmap raw data of the first character in the off-screen memory 120 and the commands or command in the graphic register at all the associated locations in the on-screen memory 122.
That is, steps 240 and 250 make the graphic engine chip 130 represent all the first characters in the on-screen memory 122 (i.e., display all the first characters at at least one first location on the frame) in a first time period, and represent all the second characters in the on-screen memory 122 (i.e., display the second characters at at least one second location on the frame) in a second time period.
Next, in step 260, it is checked whether all the characters have been completely represented. If yes, step 270 is performed, or otherwise the procedure goes back to step 240 to continue representing the second character, for example.
In step 270, it is checked whether the next frame is received. If the next frame is received, the procedure goes back to step 210, and the processing unit 110 receives and analyzes the next frame. If not, the method of displaying the characters ends.
The “Independent Part” command includes the commands to be executed by each character displayed at each location. For example, SetDstAddress( ) is for setting the display location of the character, and SetForeGroundColor( ) and SetBackGroundColor( ) are for setting the color of the character. If one character is displayed at different locations with the same color, these commands may serve as the “Share Part” command. Consequently, the operations of accessing the register of the graphic engine chip may be saved. TriggerBitbIt( ) is for triggering the graphic engine chip 130 to start representing.
Conventionally, if one character appears in a frame N times and the “Share Part” command needs to access the register M times, the graphic engine chip needs M×N access commands to display the character at all the corresponding locations according to the conventional character displaying method. In the embodiment of the invention, the graphic engine chip only needs to execute the “Share Part” command once on the character because the same character at different locations is simultaneously displayed on the display unit. Compared with the prior art method, the method according to the embodiment of the invention saves M×(N−1) operations of accessing the register so that the system efficiency of the displaying device is effectively enhanced.
Preferably, the subtitle data received by the displaying device according to the embodiment of the invention is closed caption data or teletext data. In the character link list of the embodiment of the invention, only the letters are illustrated as an example. In practice, all the characters of the subtitle data may be the characters, such as letters, digits, punctuation marks or control symbols, having the high repetition rate.
The embodiment of the invention can greatly decrease the number of times of accessing the register by the graphic engine chip, and can also reduce the consumed memory bandwidth for displaying the subtitle data of one frame so that the used efficiency of the displaying device can be effectively enhanced. In addition, the graphic engine chip can access the register according to some common commands to enhance the parallel processing and thus to enhance the processing efficiency of the graphic engine chip.
While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Number | Date | Country | Kind |
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095134318 | Sep 2006 | TW | national |