[Ffmpeg-devel] [RFC] av_random...

Michael Niedermayer michaelni
Wed Jan 10 00:46:53 CET 2007


Hi

On Tue, Jan 09, 2007 at 05:03:20PM -0600, Ryan Martell wrote:
> On Jan 9, 2007, at 4:47 PM, Michael Niedermayer wrote:
> 
> >Hi
> >
> >On Tue, Jan 09, 2007 at 04:03:21PM -0600, Ryan Martell wrote:
> >[...]
> >>For the record, the timing units I sent before were only timing the
> >>generate_untempered function, since it's only called every
> >>AV_RANDOM_N times av_random is called.
> >>
> >>Final question: typically, I use time(NULL) to initialize the seeds
> >>of a random number generator.  Since ffmpeg says don't use time
> >>(NULL), what's the best pseodo-random seed generator to use?
> >
> >0 should do
> 
> Not really; then it won't be even random- the GUID of everyone (in  
> asf.c for my mms stuff, that started this all), will always be the  
> same for every user out there.  The seed must be initialized with  
> something that's at least pseudo random.

some ids in some protocol which wont be stored can be set to time(0)
or av_random() with time(0) seed
its encoding and muxing where storing time(0) somehow is highly problematic
telling the server the current time isnt a problem, the server already
knows it from its own time(0) ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
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