[FFmpeg-user] questions about libavcodec

[卜弋天]

Hi Carl:      actually, what i met is the same libavcodec can run well on a ARM Cortex-A9-Neon smart phone, but it crashs because of un-alignment on another Cortex-A9 Neon smart phone, so i am very confused about how this can happen, and i don't how to investigate this issue. because i only get the libavcodec binary image, i don't know how to get the version of this library. can you give me some suggesting? thanks very much.  Best Regards
 > To: ffmpeg-user at ffmpeg.org
> From: cehoyos at ag.or.at
> Date: Mon, 27 Feb 2012 09:58:42 +0000
> Subject: Re: [FFmpeg-user] questions about libavcodec
> 
> 卜弋天 <buyit <at> live.cn> writes:
> 
> > 1. when compiling, how can i specify this library is compiled for ARM? 
> 
> I suspect you have to specify --target=arm
> 
> > and it includes NEON instruction supports? 
> 
> Use --disable-neon if you don't want neon support.
> 
> (So far, ./configure --help should have answered the questions, 
> if this is not true, please suggest improvements.)
> 
> > 2. suppose ARCH_ARM and HAVE_NEON are defined, which i mentioned in
> > question 1, does it mean this library can only be executed on ARM 
> > platform and the ARM chipset must have NEON module? 
> 
> I suspect so, but please test.
> 
> > 3. suppose the answer of quesion 2 is yes, then how can user choose 
> > libavcodec.so as they want? for example, there is an Android 
> > application "ROAMSAVE", it will use libavcodec.so, then how can i 
> > choose a suitable version libavcodec.so for roamsave? suppose i do 
> > not have any source code, and just want to download this
> > library from internet, how can i find the correct libavcodec?
> 
> I don't understand how this should be possible on any platform, 
> please explain.
> 
> For the problems with insufficient alignment, afaiu, you already 
> have patches for some crashes, please send them to -devel.
> 
> Thank you, Carl Eugen
> 
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