Difference between revisions of "AppleJPEGDriver"

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(Added note about IOSurface caching)
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'''AppleJPEGDriver''' is a kernel-extension providing accelerating encoding and decoding JPEG images via {{fwlink|IOSurface}}s, esp. for those with [http://en.wikipedia.org/wiki/YUV422 YUV color space]. It powers the {{fwlink|AppleJPEG}} for decoding, {{fwlink|Camera}} for encoding, and {{fwlink|Celestial}} for both.
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'''AppleJPEGDriver''' is a kernel-extension providing accelerating encoding and decoding JPEG images via {{fwlink|IOSurface}}s, especially for those with [http://en.wikipedia.org/wiki/YUV422 YUV color space]. It powers the {{fwlink|AppleJPEG}} for decoding, {{fwlink|Camera}} for encoding, and {{fwlink|Celestial}} for both.
  
 
== Methods ==
 
== Methods ==
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</source>
 
</source>
  
For best results, use an IOSurfaces that have the kIOSurfaceCacheMode property set to kIOMapInhibitCache.
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For best results, use an IOSurface that has the kIOSurfaceCacheMode property set to kIOMapInhibitCache.
  
 
{{occlass|library=IOKit.framework|navbox=1}}
 
{{occlass|library=IOKit.framework|navbox=1}}

Revision as of 02:34, 29 September 2013

AppleJPEGDriver is a kernel-extension providing accelerating encoding and decoding JPEG images via IOSurfaces, especially for those with YUV color space. It powers the AppleJPEG for decoding, Camera for encoding, and Celestial for both.

Methods

Selector Action Input Output
0 initializeDecoder - -
1 startDecoder struct JPEGDriverArgs (40 bytes) 40 bytes of stuff
2 initializeEncoder - -
3 startEncoder struct JPEGDriverArgs (40 bytes) 40 bytes of stuff.

where

struct JPEGDriverArgs {
  int must_be_zero_1;
  IOSurfaceID src_surface /*in*/;
  size_t src_size /*in*/;
  int must_be_zero_2;
  IOSurfaceID dest_surface /*in*/;
  size_t dest_size /*in*/;
  size_t result_size /*out*/;
  size_t dest_width /*in*/;
  size_t dest_height /*in*/;
  int quality /*in: 4 gives decent quality */;
};

For best results, use an IOSurface that has the kIOSurfaceCacheMode property set to kIOMapInhibitCache.