[FFmpeg-devel] Added require fallback for libmfx in the case that pkg-config cannot find libmfx

[wm4]

On Fri, 5 May 2017 09:42:51 +0200
Clément Bœsch <u at pkh.me> wrote:

> On Fri, May 05, 2017 at 12:11:27AM -0700, Aaron Levinson wrote:
> > On 4/19/2017 10:43 AM, Aaron Levinson wrote:  
> > > On 4/14/2017 6:51 PM, Aaron Levinson wrote:  
> > >> From e0c73c054add0137901d0bf7a7893e42e7e566c8 Mon Sep 17 00:00:00 2001
> > >> From: Aaron Levinson <alevinsn at aracnet.com>
> > >> Date: Fri, 14 Apr 2017 18:38:37 -0700
> > >> Subject: [PATCH] Added require fallback for libmfx in the case that
> > >>  pkg-config cannot find libmfx
> > >>
> > >> Purpose: Added require fallback for libmfx in the case that pkg-config
> > >> cannot find libmfx.  On Linux, most people likely get libmfx via
> > >> https://github.com/lu-zero/mfx_dispatch , but on Windows, the most
> > >> well-known way to get libmfx is via the Intel Media SDK, which
> > >> provides a static build of libmfx.lib and also provides the source
> > >> code for building libmfx yourself.  If built this way, there are no
> > >> pkg-config files to be found.  The changes utilize a similar approach
> > >> to that already done for libx264 in configure.
> > >>
> > >> Comments:
> > >>
> > >> -- configure: Altered enabled libmfx step to use use_pkg_config()
> > >>    instead of require_pkg_config(), and, if use_pkg_config() fails, it
> > >>    falls back to require().  Note that the reason that require() is
> > >>    passed -llibmfx as the last argument, instead of -lmfx, is the file
> > >>    name for the library produced from the Intel Media SDK starts with
> > >>    "libmfx".  Apparently, the filename for the library produced via
> > >>    https://github.com/lu-zero/mfx_dispatch starts with "mfx".
> > >> ---
> > >>  configure | 3 ++-
> > >>  1 file changed, 2 insertions(+), 1 deletion(-)
> > >>
> > >> diff --git a/configure b/configure
> > >> index 3bea057..b20a0b4 100755
> > >> --- a/configure
> > >> +++ b/configure
> > >> @@ -5819,7 +5819,8 @@ enabled libgsm            && { for gsm_hdr in
> > >> "gsm.h" "gsm/gsm.h"; do
> > >>                                 done || die "ERROR: libgsm not found"; }
> > >>  enabled libilbc           && require libilbc ilbc.h
> > >> WebRtcIlbcfix_InitDecode -lilbc
> > >>  enabled libkvazaar        && require_pkg_config "kvazaar >= 0.8.1"
> > >> kvazaar.h kvz_api_get
> > >> -enabled libmfx            && require_pkg_config libmfx
> > >> "mfx/mfxvideo.h" MFXInit
> > >> +enabled libmfx            && { use_pkg_config libmfx "mfx/mfxvideo.h"
> > >> MFXInit ||
> > >> +                               { require libmfx "mfx/mfxvideo.h"
> > >> MFXInit -llibmfx && warn "using libmfx without pkg-config"; } }
> > >>  enabled libmodplug        && require_pkg_config libmodplug
> > >> libmodplug/modplug.h ModPlug_Load
> > >>  enabled libmp3lame        && require "libmp3lame >= 3.98.3"
> > >> lame/lame.h lame_set_VBR_quality -lmp3lame
> > >>  enabled libnut            && require libnut libnut.h nut_demuxer_init
> > >> -lnut
> > >>  
> > > 
> > > Pinging this patch submission again.
> > > 
> > > Thanks,
> > > Aaron Levinson  
> > 
> > And again.  This patch is pretty straightforward, and considering that this approach was deemed suitable for libx264  
> 
> It wasn't, Carl Eugen insisted in doing this against everyone opinion, but
> we tolerated his whim because he didn't want to use or install a 80kB
> package installed on virtually every system that supports x264.
> 
> Anyway, here is a nasty side effect of doing this: you use PKG_CONFIG_PATH
> to make sure it's linking against a specific local build of your lib, but
> you did it wrong and it ends up linking silently against the system one
> instead of failing like you would like to.
> 
> We predicted that allowing this hack for x264 was going to bring up
> patches like this and we were right.
> 
> So maybe we should actually drop the hack for libx264.

+1

> 
> Back to your issue: you should fix the .pc in the upstream project, this
> is the correct fix.

+1