[MPlayer-users] Segmentation fault in pre5

[Martin Simmons]

>>>>> On Sat, 16 Oct 2004 18:06:50 -0400, D Richard Felker III <dalias at aerifal.cx> said:
> On Sat, Oct 16, 2004 at 08:33:26PM +0200, Stefan Sassenberg wrote:
> > On Fri, Oct 15, 2004 at 07:19:32PM -0700, Corey Hickey wrote:
> > > Stefan Sassenberg wrote:
> > > > Hello,
> > > > 
> > > > I frequently have segmentation faults when mencoding a movie.
> > > > Unfortunately this happens at different positions. I can provide some
> > > > information about this problem. I should add that I had other problems
> > > > of similar kind that I only solved by rebuilding mencoder with
> > > > ./configure --disable-mmx2 which I'm currently using.
> > > > 
> > > 
> > > Are you saying that it happens at a different position each time you try
> > > the same command on the same file? If so, then you probably have
> > > unstable hardware. I've found that mencoder is very intolerant of
> > > overclocking, probably from a combination of working the CPU very hard
> > > and the time it takes to encode.
> > > 
> > > If you are overclocking, try overclocking a little less; or, try cooling
> > > your CPU better.
> > > 
> > Correct. Just like the other problem I once had that I mentioned above.
> > I also thought about hardware problems, but mencoder is the only application
> > that shows errors like these and I'm not overclocking. Heat problems
> > might be the cause anyway.
> 
> anything that happens at a random location each time you run a program
> is _definitely_ heat-caused. mencoder doesn't read from /dev/urandom
> and pick what to do based on the results. the results of each run are
> entirely deterministic and won't vary from one to another.

There is plenty of other non deterministic problems that are not caused by
heat or urandom.  Particular cases that I've seen (not in mencoder yet):

- timing-related issues for interaction between threads or processes

- hardware bugs (CPUs with broken borderline cases in the MMU)

- OS bugs (causing registers to be corrupted)

__Martin