Tuesday, September 7th, 2010

WebPagetest and PageSpeed join up via PageSpeed SDK

Category: Performance

Steve Souders just pointed me to the great news that two great open source performance projects are working well together:

Pat Meenan just blogged about Page Speed results now available in Webpagetest. This is a great step toward greater consistency in the world of web performance, something that benefits developers and ultimately benefits web users.

The Page Speed SDK gives a path for folks to unify behind standard performance metrics and results. Great work!

Posted by Dion Almaer at 12:47 pm

2.3 rating from 3 votes


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Hmm. I can’t really say I trust the results of a system that recommends all pngs be reduced to 8-bit. Don’t you think there might be a reason I’m using 32-bit?

Comment by okonomiyaki3000 — September 7, 2010

@okonomiyaki3000: It sounds like you are concerned that the 32bit to 8bit conversion is lossy, but that is not the case. All Page Speed image transformations are lossless (the image looks identical on the screen before and after).

Page Speed suggests using 8bpp *paletted* images when it is possible to losslessly transform from 32bpp. See http://www.libpng.org/pub/png/pngintro.html for more information. In the 8bit paletted format, each pixel is an index into a color table which contains a full 24bit RGB entry. For alpha PNG supports the sRGB chunk which encodes that channel, if necessary. So you can still capture 32bit color per pixel, but more efficiently than encoding each pixel using 32bits. Hope that helps!

Comment by bmcquade — September 22, 2010

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