libjpeg vs. libjpeg-turbo

[Mihai Moldovan]

On 22.05.2015 02:49 AM, Ryan Schmidt wrote:
> On May 20, 2015, at 5:11 AM, Clemens Lang wrote:
>> Yes, we would have to revbump all dependents of the jpeg port if we do 
>> this. Since it is unlikely that mozjpeg and libjpeg-turbo will ever 
>> implement the changes to become compatible with libjpeg.9.dylib there is no
>> way to avoid the rebuild for this kind of switch.
> 
> I wondered why libjpeg-turbo would not incorporate libjpeg 9 features, and
> found this article explaining why:
> 
> http://libjpeg-turbo.org/About/Jpeg-9

I'd be surprised to see any software use jpeg 9 features.


> Based on the above article, and the referenced instances of how the current
> developer of libjpeg is interacting with the community,

You put that very diplomatically...


> I'm open to replacing jpeg with libjpeg-turbo, with the option to use the
> mozjpeg fork of libjpeg-turbo instead.

Yes and yes.


> This would involve verifying that libjpeg-turbo works (or at least builds)
> correctly on PowerPC and Intel Macs running 10.4 and up.

This could become an issue on PPC and older versions. Who can test, whether
current libjpeg-turbo builds?


> Then, assuming it does, identifying all ports that link with libjpeg;
> changing the dependency from port:jpeg to
> path:lib/libjpeg.dylib:libjpeg-turbo; increasing their revision; and marking
> jpeg as replaced_by libjpeg-turbo.

ACK.


> I count over 200 ports marked as depending on jpeg; there might be more that
> aren't marked.

212 if my calculations are correct. The pool is surprisingly low.


> It would be good to verify that at least a good portion of those can compile
> with libjpeg-turbo before committing, though it sounds like it's already
> pretty well-tested in other distributions.

I'd skip that. If it works with jpeg, it's supposed to work with libjpeg-turbo
(mind it being a drop-in replacement.)

Making sure that libjpeg-turbo builds is higher priority.



Mihai

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