Re: [FFmpeg-devel] [PATCH] avutil/eval: Use even better PRNG

2024-01-19 Thread Michael Niedermayer
On Fri, Jan 19, 2024 at 09:53:46AM +0100, Michael Koch wrote: > There is still a small problem with the random generator, but this has > nothing to do with the recent changes. > If the random() expression is used in the geq filter, then multiple pixels > get the same sequence of random numbers. > A

Re: [FFmpeg-devel] [PATCH] avutil/eval: Use even better PRNG

2024-01-19 Thread Michael Koch
There is still a small problem with the random generator, but this has nothing to do with the recent changes. If the random() expression is used in the geq filter, then multiple pixels get the same sequence of random numbers. As can be shown with this command, where the frame has only two pixels

Re: [FFmpeg-devel] [PATCH] avutil/eval: Use even better PRNG

2024-01-15 Thread Michael Niedermayer
On Sun, Jan 14, 2024 at 03:14:23PM +0100, Stefano Sabatini wrote: > On date Saturday 2024-01-13 04:51:06 +0100, Michael Niedermayer wrote: > > This is the 64bit version of Chris Doty-Humphreys SFC64 > > > > Compared to the LCGs these produce much better quality numbers. > > Compared to LFGs this n

Re: [FFmpeg-devel] [PATCH] avutil/eval: Use even better PRNG

2024-01-14 Thread Stefano Sabatini
On date Saturday 2024-01-13 04:51:06 +0100, Michael Niedermayer wrote: > This is the 64bit version of Chris Doty-Humphreys SFC64 > > Compared to the LCGs these produce much better quality numbers. > Compared to LFGs this needs less state. (our LFG has 224 byte > state for its 32bit version) this h

[FFmpeg-devel] [PATCH] avutil/eval: Use even better PRNG

2024-01-12 Thread Michael Niedermayer
This is the 64bit version of Chris Doty-Humphreys SFC64 Compared to the LCGs these produce much better quality numbers. Compared to LFGs this needs less state. (our LFG has 224 byte state for its 32bit version) this has 32byte state Also the initialization for our LFG is slower. This is also much

Re: [FFmpeg-devel] [PATCH] avutil/eval: Use even better PRNG

2024-01-10 Thread Michael Niedermayer
On Wed, Jan 10, 2024 at 11:48:33PM +0100, Stefano Sabatini wrote: > On date Tuesday 2024-01-09 02:55:21 +0100, Michael Niedermayer wrote: [...] > > > > static const AVClass eval_class = { > > @@ -174,7 +175,7 @@ struct AVExpr { > > } a; > > struct AVExpr *param[3]; > > double *va

Re: [FFmpeg-devel] [PATCH] avutil/eval: Use even better PRNG

2024-01-10 Thread Stefano Sabatini
On date Tuesday 2024-01-09 02:55:21 +0100, Michael Niedermayer wrote: > This is the 64bit version of Chris Doty-Humphreys SFC64 > > Compared to the LCGs these produce much better quality numbers. > Compared to LFGs this needs less state. (our LFG has 224 byte > state for its 32bit version) this ha

[FFmpeg-devel] [PATCH] avutil/eval: Use even better PRNG

2024-01-08 Thread Michael Niedermayer
This is the 64bit version of Chris Doty-Humphreys SFC64 Compared to the LCGs these produce much better quality numbers. Compared to LFGs this needs less state. (our LFG has 224 byte state for its 32bit version) this has 32byte state Also the initialization for our LFG is slower. This is also much