[x264-devel] Poor coding efficiency with ARM asm enabled

[Henrik Gramner]

On Mon, Dec 26, 2016 at 3:22 PM, 林镇安 <linzhenan at kuaishou.com> wrote:
>
> Dear experts,
>
> I compared the coding efficiency of x264, and only to find ~20% loss with ARM asm enabled when using CRF/ABR. I want to know what is the cause?

Hi

The ARM results definitely seems like a bug somewhere, so thanks for
the bug report :)

The x86 results are as expected due to some assembly optimizations
intentionally doing things slightly differently compared to the C
counterparts. This behavior can be avoided using the --cpu-independent
option which disables those specific assembly subroutines.

Could you try running the problematic ARM tests using the
--cpu-independent option if it makes any difference to help us narrow
down the problem (I don't have any ARM dev machine so I can't test it
myself)?

Henrik