Re: [ptxdist] libjpeg-turbo and libjpeg

[Michael Olbrich <m.olbrich@pengutronix.de>]

Hi,

On Wed, Feb 14, 2018 at 10:57:06AM +0100, Guillermo Rodriguez Garcia wrote:
> 2018-02-14 10:22 GMT+01:00 Guillermo Rodriguez Garcia <
> guille.rodriguez@gmail.com>:
> > No build issues here and I can confirm that both gst-plugins-good1 (with
> > the jpeg plugin) and imagemagick both work fine with libjpeg-turbo on my
> > target platform.
> >
> > Some comments:
> >
> > - According to the documentation (https://github.com/libjpeg-
> > turbo/libjpeg-turbo/blob/master/BUILDING.md), NASM or YASM are required
> > if building x86 or x86-64 SIMD extensions. I have not verified this ,yself
> > (I'm building for an ARM target) but since we are enabling SIMD, shouldn't
> > the .in file select HOST_NASM? (ideally for ARCH_X86 only but it seems that
> > this can't be checked in the .in file?)

Yes the dependency should be there. Hopefully my build tests will tell me
the same thing :-).
It's true, that we cannot define the dependency for x86 only, but maybe I
can hack this. I didn't bother with it for gst-libav but libjpeg is
significantly smaller. I need to think about this.

> > - For ARM targets, --with-simd requires NEON support. Perhaps the .make
> > file should do something like this:
> >
> > # For ARM, enable SIMD extensions only if NEON is available
> > ifdef PTXCONF_ARCH_ARM_NEON
> > LIBJPEG_CONF_OPT += --with-simd
> > endif
> > # For architectures other than ARM, enable SIMD extensions unconditionally
> > ifndef PTXCONF_ARCH_ARM
> > LIBJPEG_CONF_OPT += --with-simd
> > endif

Indeed.

> BTW one more comment:
> 
> If --with-jpeg8 is specified, --with-jpeg7 has no effect. See configure.ac:
> 
>   if test "x${with_jpeg8}" = "xyes"; then
>     JPEG_LIB_VERSION=80
>   else
>     if test "x${with_jpeg7}" = "xyes"; then
>       JPEG_LIB_VERSION=70
>     else
>       JPEG_LIB_VERSION=62
>     fi
>   fi
> 
> So you may want to remove --with-jpeg7 from the .make file.

We try to set all regular options, even if they are no-ops. This way, the
next person doing a version bump won't have to recheck existing options.

Michael

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