From 8ceb37d5ad730b93e4a277b74a5279c5d1f7864a Mon Sep 17 00:00:00 2001 From: Stefano Sabatini Date: Mon, 1 Jan 2024 20:38:03 +0100 Subject: [PATCH] doc/utils/eval: clarify meaning of random* seed value Possible address trac issue: http://trac.ffmpeg.org/ticket/10763 --- doc/utils.texi | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/doc/utils.texi b/doc/utils.texi index 76e704fc3c..2f18a61bfd 100644 --- a/doc/utils.texi +++ b/doc/utils.texi @@ -944,11 +944,23 @@ Return a pseudo random value between 0.0 and 1.0. @var{idx} is the index of the internal variable which will be used to save the seed/state. +To initialize the seed, you need to store the seed value as a 64-bit +unsigned integer in the internal variable with index @var{idx}. + +For example, to store the seed with value @code{42} in the internal +variable with index @code{0} and print a few random values: +@example +st(0,42); print(random(0)); print(random(0)); print(random(0)) +@end example + @item randomi(idx, min, max) Return a pseudo random value in the interval between @var{min} and @var{max}. @var{idx} is the index of the internal variable which will be used to save the seed/state. +To initialize the seed, you need to store the seed value as a 64-bit +unsigned integer in the internal variable with index @var{idx}. + @item root(expr, max) Find an input value for which the function represented by @var{expr} with argument @var{ld(0)} is 0 in the interval 0..@var{max}.