Vladimir Pantelic vladoman@gmail.com writes:
Mandeep Kumar wrote:
Hi All,
I have done some benchmarking on OMAP4 running Ubuntu for various versions of libjpegs. Benchmarks were collected with modified version of djpeg that prints out ms time taken for decoding. Sample used for benchmarking is a 12MP image downloaded from a photography website. Here are the results:
...
libjpeg-turbo trunk version that has NEON patches (5 runs). *http://libjpeg-turbo.svn.sourceforge.net/viewvc/libjpeg-turbo/*
Decoding Time for Run 1: 1068 ms Decoding Time for Run 2: 1065 ms Decoding Time for Run 3: 1093 ms Decoding Time for Run 4: 1066 ms Decoding Time for Run 5: 1067 ms
*Median Decoding Time: 1067 ms*
One remark:
a 12MP image decoded in 1076ms equals ~12MP/s decoding speed.
decoding a 640x480 MJPEG file on a 1GHz OMAP4 using libavcodec gives me an average decoding time per frame of ~10ms which yields:
640x480/10ms = ~30MP/s
so roughly 2.5 times faster.
Either I am doing something wrong or this libjpeg-turbo is not so turbo.
Libjpeg (turbo or regular) is full of inefficiencies. I guess they all add up.