The original blog post is not responding, presumably due to traffic, so I am going off the screenshot provided by Ajaxian. The quotes from Ajaxian say that the original author suggested that the V8 and Nitro engines were faster at doing JPEG encoding than the AS3 VM. The times given in the screenshot list 703ms and 504ms which I take as the same test with 2 different results. Using the size of the image from the screenshot as 200x255 image I used a AS3 code test, made in Flex, that compares different encoding libraries speed in AS3. The slowest of these libraries encoded a same size JPEG in 270ms and the fastest at 16ms. This test only shows that the JPGEncoder class from the as3corelib library is slower than his JavaScript implementation, not that the AS3 VM is slower than Nitro or V8.
Without the blog site being up I can't do any further testing though to use identical JPG source images but I do take notice when one engine is claimed faster than another. JavaScript and ActionScript are very similar so I suspect most of these libraries, other than the C/C++ based ones, can be ported to JavaScript as he mentioned doing based off the as3corelib implementation, JPGEncoder.
Edit: He said that the Nitro and V8 engines were faster but his test proved otherwise. His conclusion was that it was only slower because JavaScript has no static types, vectors, byte-arrays and is not pre-compiled.
Additional Edit: Cool! JPEG encoding in JavaScript :)
Without the blog site being up I can't do any further testing though to use identical JPG source images but I do take notice when one engine is claimed faster than another. JavaScript and ActionScript are very similar so I suspect most of these libraries, other than the C/C++ based ones, can be ported to JavaScript as he mentioned doing based off the as3corelib implementation, JPGEncoder.
You can see the source I used to compare AS3 JPEG encoding libraries here http://segfaultlabs.com/blog/post/asynchronous-jpeg-encoding
Edit: He said that the Nitro and V8 engines were faster but his test proved otherwise. His conclusion was that it was only slower because JavaScript has no static types, vectors, byte-arrays and is not pre-compiled.
Additional Edit: Cool! JPEG encoding in JavaScript :)