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来自「JPEG教程,包括视频图象的压缩与解压缩,以及其他视频处理算法.」· HTML 代码 · 共 32 行
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<TITLE>JPEG image compression FAQ, part 1/2 - [19] Could an FPU speed up JPEG? How about a DSP chip?</TITLE>
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Parent document is top of "<A NAME=up HREF="faq.html" tppabs="http://www.cis.ohio-state.edu/hypertext/faq/usenet/jpeg-faq/part1/faq.html"><I>JPEG image compression FAQ, part 1/2</I></A>"<BR>
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<H1>[19] Could an FPU speed up JPEG? How about a DSP chip?</H1>
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Since JPEG is so compute-intensive, many people suggest that using an
FPU chip (a math coprocessor) should speed it up. This is not so.
Most production-quality JPEG programs use only integer arithmetic and so
they are unaffected by the presence or absence of floating-point hardware.
It is possible to save a few math operations by doing the DCT step in
floating point. On most PC-class machines, FP operations are enough slower
than integer operations that the overall speed is still much worse with FP.
Some high-priced workstations and supercomputers have fast enough FP
hardware to make an FP DCT method be a win.
DSP (digital signal processing) chips are ideally suited for fast repetitive
integer arithmetic, so programming a DSP to do JPEG can yield significant
speedups. DSPs are available as add-ons for some PCs and workstations;
if you have such hardware, look for a JPEG program that can exploit it.
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