[vlc-devel] [vlc-commits] contrib: enable NEON runtime selection for ffmpeg

[Rafaël Carré]

Le 03/01/2013 15:14, Rémi Denis-Courmont a écrit :
> On Thu,  3 Jan 2013 15:01:58 +0100 (CET), git at videolan.org (Rafaël Carré)
> wrote:
>> vlc | branch: master | Rafaël Carré <funman at videolan.org> | Thu Jan  3
>> 15:01:11 2013 +0100| [d2e405e02c9530b6abdfca4237790addd463c7b7] |
>> committer: Rafaël Carré
>>
>> contrib: enable NEON runtime selection for ffmpeg
>>
>> This is explicitely done for android only, since we lost the
>> benefits of some inline NEON asm
> 
> That does not seem to be what the commit actual does.

True, what is explicitely done for android only is remove -mfpu=neon
from CFLAGS

> 
>>>
> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=d2e405e02c9530b6abdfca4237790addd463c7b7
>> ---
>>
>>  contrib/src/ffmpeg/rules.mak |    5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/contrib/src/ffmpeg/rules.mak b/contrib/src/ffmpeg/rules.mak
>> index 2647fcf..4798065 100644
>> --- a/contrib/src/ffmpeg/rules.mak
>> +++ b/contrib/src/ffmpeg/rules.mak
>> @@ -53,11 +53,14 @@ endif
>>  # ARM stuff
>>  ifeq ($(ARCH),arm)
>>  FFMPEGCONF += --arch=arm
>> -ifdef HAVE_NEON
>> +ifdef HAVE_ARMV7A
> 
> When is ARMv7-A synonym with NEON since?

Hm right, we should unconditionally build NEON code since the NEON unit
could be present on armv6? armv5?

Måns?

>>  FFMPEGCONF += --cpu=cortex-a8 --enable-neon
>> +FFMPEG_CFLAGS += -mfpu=vfpv3-d16
>> +ifndef HAVE_ANDROID # We want NEON autodetect on Android
>>  FFMPEG_CFLAGS += -mfpu=neon
>>  endif

Perhaps we should remove -mfpu=neon altogether in fact.

>>  endif
>> +endif
>>  
>>  # MIPS stuff
>>  ifeq ($(ARCH),mipsel)