[FFmpeg-devel] [PATCH 0/5] Integer scalar product DSP functions

Christophe Gisquet christophe.gisquet at gmail.com
Thu May 9 11:23:06 CEST 2013


Hi,

I'm not going to reply all comments. This set was more as a RFC, and
indeed it seems better to try to not modify the asm.

2013/5/8 Michael Niedermayer <michaelni at gmx.at>:
>> +    AV_ZERO128(buffer_a+BLOCKSIZE);
>
> if buffer_a is moved to the context then this could be avoided
> also it would avoid the need for LOCAL_ALIGNED()

OK.

> also trying to build the code with the patch results in:

Yes, I took a shortcut here (local modification then diff against
master of too few files).

Regarding TAK and its need for 4 elements in a batch, this is probably
too costly compared to (schematically):
scalprod(a, b, length&-4)
for(i=length&-4; i<length; i++) sum += a[i]*b[i];

ie, the issue that applies for wma lossless also applies for tak.

Christophe


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