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Decompressing JPEG data into specific format, getting raw pixels
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Decompressing JPEG data into specific format, getting raw pixels


  • Subject: Decompressing JPEG data into specific format, getting raw pixels
  • From: "Sean McBride" <email@hidden>
  • Date: Tue, 15 Aug 2017 12:23:58 -0400
  • Organization: Rogue Research Inc.

Hi all,

I get some JPEG data from the network.  I want to efficiently decompress this
data into a specific format (8 bit greyscale) and have an NSData of the raw
pixels.  What's the best way to do this?

I'm currently using NSBitmapImageRep initWithData:, then testing if the result
is greyscale or RGB.  If the latter, I write my own loop to convert to
greyscale.

But I'm hoping there is some lower level API available that I can tell
explicitly that I want greyscale...

Thanks,

--
____________________________________________________________
Sean McBride, B. Eng                 email@hidden
Rogue Research                        www.rogue-research.com
Mac Software Developer              Montréal, Québec, Canada


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