| 摘要 |
PURPOSE: An apparatus and a method for generating on-screen-display messages using field doubling is provided to generate OSD(on-screen-display) messages without increasing memory bandwidth of a decoding/display system. CONSTITUTION: A method(400) begins at step 405 and proceeds to step 410 where the method(400) determines whether the Field Doubling is enabled for an OSD region. If the query is negatively answered, the method(400) proceeds to step 415 where the OSD data bytes are generated using a non-field doubling format. Method(400) then proceeds to step 440. If the query at step 410 is affirmatively answered, the method(400) proceeds to step 420 where the top and bottom field points are set to the same value in the OSD header. Since the top and bottom field (block) pointers are set to the same value, the OSD unit(150) will only need to read a single field of OSD data. In step 430, a single field of OSD data is disposed within the OSD data bytes. Namely, the OSD bitstream only carries OSD data for every other OSD line, where each OSD line comprises sufficient OSD pixels for the OSD unit(150) to display a single horizontal line in an OSD region. In step 440, the method(400) determines whether there is another OSD header. A new OSD header may be required if the various modes represented by the function bits(212) are modified. Similarly, a new header is required for each new OSD region on a frame. If the query is negatively answered, method(400) proceeds to step 450 where method(400) ends. If the query is affirmatively answered, method(400) proceeds to step 410 where the steps of 410-430 are repeated for each additional OSD header. |
