NOTE: This Technical Q&A has been
retired. Please see the Technical Q&As
page for current documentation.
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NOTE: This Technical Q&A has been
retired. Please see the Technical Q&As
page for current documentation.
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Q In a QTW codec, if it requests to write directly to hardware (optt = OPT_HWD),
then under which circumstances does VDSP_BITBLTTYPE respond with BBL_DRVR? A A codec should not care about VDSP_BITBLTTYPE. That is used by QTW internally. A codec cannot really request to do OPT_HDW unless QTW asks it to. Codecs are only permitted to downgrade QTW requests to a less efficient level during PreDecompress. QTW generally (but not always) asks for OPT_HDW first, and then goes to OPT_BMP if the codec recommends the downgrade. Sometimes QTW will ask for OPT_RAW first (for various reasons). A hardware aware codec will generally need to know the difference between banked and non-banked display adapters (VDSP_QUERYBANK). A full-featured codec will perform the following: * Support OPT_HDW for all different BMP_xxx formats (when asked to do so). * Support OPT_BMP for all different BMP_xxx formats (almost always). * Support OPT_RAW at different pixel depths (8, 16, 24). [Aug 01 1995] |
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