My numbers should only be used for relative comparison purpose as djpeg decoding time that I sent also include time to read input file from filessystem. Actual decoding speed may be higher when special modification are done in djpeg application to read input from memory.
Thanks & Regards, Mandeep
2011/6/29 Måns Rullgård mans@mansr.com
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.
-- Måns Rullgård mans@mansr.com