From: Michael Koch <astroelectronic@t-online.de>
To: ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [PATCH 2/2] doc/utils/eval: clarify meaning of random* seed value
Date: Wed, 3 Jan 2024 12:20:12 +0100
Message-ID: <c8d2e66c-dcc9-1fc1-8d86-df9940719b48@t-online.de> (raw)
In-Reply-To: <20240101193859.1038078-2-stefasab@gmail.com>
> Possible address trac issue:
> http://trac.ffmpeg.org/ticket/10763
I don't like the random generator as it is, because the first two random numbers
are very close to zero, as can be shown with this command line:
ffmpeg -loglevel repeat -f lavfi -i nullsrc=size=1x1,format=gray -vf
"geq=lum='print(random(0));print(random(0));print(random(0));print(random(0))'"
-frames 1 -y out.png 0.000000 0.000091 0.285346 0.929202 This behaviour
can be improved by inizializing the generator with a large number as
seed value. I'm not sure if it's a good idea to share the same variables
for ld() and st() (as double) and random() (as unsigned int). Wouldn't
it be better to use separate variables for random()? Michael
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next prev parent reply other threads:[~2024-01-03 11:20 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-01 19:38 [FFmpeg-devel] [PATCH 1/2] libavutil/eval: introduce UINT64_MAX constant Stefano Sabatini
2024-01-01 19:38 ` [FFmpeg-devel] [PATCH 2/2] doc/utils/eval: clarify meaning of random* seed value Stefano Sabatini
2024-01-03 11:20 ` Michael Koch [this message]
2024-01-03 16:14 ` Stefano Sabatini
2024-01-03 17:04 ` Michael Koch
2024-01-03 18:36 ` Michael Koch
2024-01-03 22:29 ` Michael Niedermayer
2024-01-02 0:10 ` [FFmpeg-devel] [PATCH 1/2] libavutil/eval: introduce UINT64_MAX constant Michael Niedermayer
2024-01-03 16:17 ` Stefano Sabatini
2024-01-03 19:40 ` Michael Niedermayer
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