Intel® Integrated Performance Primitives

Timing question involving the IPPL

This is question that involves the Intel Performance
Primitives Library (IPPL), but it is more a question about
timing on a Pentium 4 with hyperthreading using the IPPL.

I have an application that uses the IPPL on a Windows XP
system running a Pentium 4 with hyperthreading turned on,
i.e it has two logical processors, and one physical processor.
When we time calculations using the Windows GetProcessTimes
interface we get the following curious result.

Extracting YUV data from a JPEG

Does anyone know how I can extract the YUV values for each image pixel (4:4:4) using IPP 4.1? I've compiled the IJL2.0 sample and it's possible to extract them but only if the JPEG is encoded as 4:2:2 - I'd like to be able to handle different formats, e.g. a JPEG encoded as YUV 4:1:1.

If Iuse the IPPlibrary Icould convert the RGBvalues decoded from the JPEG to YUV but this seems wasteful when they were YUV to start with in the JPEG. Am I missing something?

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