libjpeg-turbo for Android available

[Christian Robottom Reis]

On Fri, Sep 02, 2011 at 10:34:47AM -0500, Tom Gall wrote:
> The initial port of Android's extensions to the current libjpeg-turbo
> codebase is complete.

Tom, you've done a spectacular job carrying the -turbo work into the
developer platform and now Android. I'm thrilled to see this come to
fruition now, and the CyanogenMod test is a great bonus -- seeing this
used on a real form-factor device means I can actually believe in it.

> The code can currently be found in git at:
> 
> http://git.linaro.org/gitweb?p=people/tomgall/libjpeg-turbo/libjpeg-turbo.git;a=summary
> 
> from the 1.2-beta-linaro-andoid branch.
> 
> Be sure to read the ANDROID.txt file for build instructions. This
> branch is SPECIFICALLY for android.

Can you give a summary of what's being added here? i.e. what happened to
Android when using libjpeg-turbo without these added patches?

I see some pretty major changes in:

    http://git.linaro.org/gitweb?p=people/tomgall/libjpeg-turbo/libjpeg-turbo.git;a=commitdiff;h=ff1f5e7ce17701b48e53b7fcb3509f40715fd2e4

It looks to me like the main changes are protected by the following
defines, which probably answers part of my question above:

    ENABLE_ANDROID_NULL_CONVERT
    ANDROID_TILE_BASED_DECODE
    ANDROID_RGB

(Ald yes, I have read ANDROID.txt which confirms the above but doesn't
tell me much else ;-)

Also, I see you adding config.h and jconfig.h files which I don't think
you want to have committed, right?

Do you really want an android/ config subdirectory?

> I have not yet started to do performance comparisons between the old
> jpeg and libjpeg-turbo on android. That needs to be done.

This might be Zach's next favorite demo!

You might want to try out the toolchain guys' latest -03 and assorted
optimization madness to see if they make a difference when you do that.

> Also from the android extensions, support for ash and one optimization
> for armv6 was not included. Both however are reasonable optimizations
> and I can see including them at a future date.

What is the "support for ash" piece?

Good job!
-- 
Christian Robottom Reis, Engineering VP
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