[FFmpeg-devel] Multimedia extensions run-time support check
Tue Jun 24 17:43:49 CEST 2008
(I know this is not a very interesting matter, but it's a good way
for me to start messing with FFmpeg code; if noone cares, let
me know and I'll use some adhoc solution that fits my needs.)
Currently to know what multimedia extensions are supported,
the code checks the value of mm_flags or the return value of
mm_support() (cf. dsputil.h).
My understanding is that this is only used to setup things at
However I find things are inconsistent. For instance:
- mm_support is always declared but only defined for MMX,
IWMMXT (Xscale) and PPC
- mm_flags is declared for ARMV4L but only defined for
This is not a big deal at the moment since it only breaks
the build of some test programs for some configs, such as
dct-test when either MMX is not defined or when building
for ARM without IWMMXT.
Currently I only see two solutions:
1. correctly protect declarations in dsputil.h depending
2. always define fake mm_flags and mm_support that
are or return zero.
I have certainly overlooked something, but as I wrote,
I'm new to FFmpeg :-)
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