Bug#870676: ffmpeg requires NEON on armhf, which is not part of the ARMv7 ABI

[James Cowgill]

Hi,

On 09/08/17 04:59, Edmund Grimley Evans wrote:
> James:
>> I think the runtime is working, but this is the testcase from the SIGBUS
>> bug which you can use:
>>
>> ffmpeg -f lavfi -i testsrc=s=32x32:d=0.1 -strict -2 -c:v libx264rgb -f avi libx264rgb.avi -y -hide_banner -nostdin
>> ffmpeg -strict -2 -i libx264rgb.avi -t 1 -c:v rawvideo -c:a pcm_s32le -f nut /dev/null -y -hide_banner -nostdin
>>
>> Since the SIGBUS bug occurs in NEON code, if the runtime detection is
>> working, this will _only_ fail on machines with NEON and work on
>> non-NEON machines.
> 
> This bug was closed while I was sleeping, but I will mention anyway
> that with 7:3.3.3-1 those commands give a SIGBUS, as expected, but
> only if /proc is mounted.
> 
> Presumably with the fixed version, 7:3.3.3-2, performance will be
> measurably worse on a system with NEON when /proc is not mounted.
> 
> Upstream should probably switch to using getauxval(). Do you want to
> suggest it to them?

I've filed it upstream here:
https://trac.ffmpeg.org/ticket/6578

James

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