Method and device for realizing on-screen display (OSD) of characters

Abstract

The invention discloses a method and a device for realizing on-screen display (OSD) of characters. The method comprises the following steps of: downloading dot matrix information corresponding to the common tag characters and the characters in an American standard code for information interchange (ASCII) character bank to a digital signal processor (DSP) memory; storing the dot matrix information corresponding to characters in a wide-byte character bank in a memory of a host; receiving an OSD display command and judging the types of to-be-displayed OSD characters; if the to-be-displayed OSD characters are the common tag characters and / or belong to the ASCII characters in the ASCII character bank, acquiring the dot matrix information corresponding to the to-be-displayed OSD characters from the memory of the DSP; if the to-be-displayed OSD characters are the characters in the wide-byte character bank, downloading the dot matrix information corresponding to the character from the memory of the host to the memory of the DSP; and uploading the dot matrix information corresponding to the to-be-displayed OSD characters to a video image to display. By using the method and the device, the required dot matrix character bank does not need to be downloaded to the memory of the DSP in advance.

Description

technical field [0001] The invention relates to the technical field of digital video, in particular to a method and device for realizing character display on a screen. Background technique [0002] On-screen display (OSD, on-screen display) is mainly used to superimpose text information on video images, such as time, location, etc., so as to provide more additional information for video content. OSD can be used as a description and supplement of video images, and can be transmitted and stored along with the video stream; it can also provide users with a friendly man-machine interface, enabling users to obtain more additional information. [0003] At present, OSD is mainly composed of characters, including numbers, letters, Chinese characters, special symbols, etc. Therefore, in order to support different languages, different fonts need to be used. For example, supporting English requires ASCII fonts, supporting Chinese requires GB2312 fonts, and supporting Russian requires R...

AI Technical Summary

Problems solved by technology

[0005] It can be seen that when the existing OSD character display is realized, it is necessary to download the possibly used dot matrix font library, such as the Chinese font library of GB2312 encoding, or the Japanese font library and the Russian font library, to the memory of the DSP of the system, and these dot matrix fonts The font library is relatively large (for example, the Chinese font library encoded in GB2312 is about 260KB), which will occupy more DSP memory space, affect the use of other functions of the entire system, and limit future function expansion

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