[FFmpeg-devel] Interpolation algorithms for FFmpeg

[Sebastian Vater]

Jason Garrett-Glaser a ?crit :
> On Tue, Aug 3, 2010 at 1:08 PM, Sebastian Vater
> <cdgs.basty at googlemail.com> wrote:
>   
>> Loren Merritt a ?crit :
>>     
>>> On Tue, 3 Aug 2010, Sebastian Vater wrote:
>>>       
>>>> If I'm not wrong then most of the speed gain can be achieved by doing a
>>>> 100% integer (fixed point) version?
>>>>         
>>> float->int16 approximately doubles throughput. Or converting only most
>>> of it to int16 (which I have done) is 1.8x so far (over nnedi3-0.9.1).
>>> int8 would be faster, but also loses a signficant amount of precision,
>>> so I ruled that out.
>>> The remaining optimization idea I had involves exploiting isotropy to
>>> reduce the number of edge orientations the ANN has to deal with. But
>>> that involves retraining, so it'll take longer to test.
>>>       
>> Did you test float->int also? Also target CPU "optimal" int? Is there
>> any difference?
>>     
>
> What is "int"?  Do you mean 32-bit int?  32-bit int will be exactly
> twice as slow as 16-bit, given that you'll be able to fit 2x fewer
> elements in each register.  Possibly worse, given the lack of many
> important 32-bit operations in SSE (and the abundance of 16-bit ones).
>   

Oh I meant, for example, a simple:
int i;

;-)

Didn't know that you were speaking of a SSE optimized algorithm. That
clarifies a lot of things.

-- 

Best regards,
                   :-) Basty/CDGS (-: