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Bug#379497: [sms@2BSD.COM: Re: [Mjpeg-developer] jpeg-xmms build issues with gcc 4.1]


see attached message from upstreams devel list.

----- Forwarded message from "Steven M. Schultz" <sms@2BSD.COM> -----

From: "Steven M. Schultz" <sms@2BSD.COM>
Date: Fri, 28 Jul 2006 19:52:48 -0700 (PDT)
To: Developer mailing list <mjpeg-developer@lists.sourceforge.net>
Subject: Re: [Mjpeg-developer] jpeg-xmms build issues with gcc 4.1
Reply-To: Developer mailing list <mjpeg-developer@lists.sourceforge.net>

On Fri, 28 Jul 2006, Michael Ablassmeier wrote:

> jpeg-mmx fails to build from source using gcc 4.1:

	That's not surprising - seems each new version of gcc breaks 
	something ;)

> I'am no ASM/SSE Expert, so i think it would be best if you guys could
> have a look at the patches provided in the above link and could tell me
> if its safe to include them in the package. 

	jpeg-mmx was deprecated a while ago.  It was problematic in many
	ways: it does not build on AMD64 platforms, was causing programs
	to crash, is not compatible with libquicktime (you can not use
	jpeg-mmx and libquicktime in the same program due to symbol name
	clash/conflict), is not usable on PPC systems, there are other
	reasons but that should be enough for now.

	Support for jpeg-mmx was removed from mjpegtools quite some time
	while ago (January 2006 to be exact). Too many problems and the speed 
	improvement wasn't all that great even when the routines did work.
	From the spec file:

" jpeg-mmx is not supported, it crashes on IA32 systems, will not build on
  X86_64 or PPC systems and even when it did work didn't provide  much of
  a speedup (jpeg decoding is a small portion of the overall encoding process)"

	My advice would be to ignore jpeg-mmx.  if you are using the
	cvs version of mjpegtools then ignoring jpeg-mmx will be done 
	automatically for you (nothing in configure.ac will look for jpeg-mmx).

	Steven Schultz
Mjpeg-developer mailing list

----- End forwarded message -----

    - michael

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