[vlc-devel] Re: VLC Bug in v. 0.8.2: Jerky Menu DVD Playing in Windows

[John Michael Williams]

Hi Benjamin.

One guess:  Several forum posters, and I, have
noticed this problem to occur on a newly-installed OS.
Why, I don't know.  However, there may be some
sort of OS feedback interacting with an adaptive
parameter somewhere.

No VLC option that I know of has had any noticeable effect
on the problem, and I think I've tried them all.

Answers to your questions below.

Benjamin Pracht wrote:

> On Sun, Jul 03, 2005, John Michael Williams wrote :
> 
>>You can get full detail on this bug, which has been
>>confirmed by other users in Windows 2000 and Windows XP,
>>under the forum title "VLC 0.8.2 Plays DVD w. Menues
>>jerkily in Win2k".
>>
>>My most recent link to the web page is:
>>http://forum.videolan.org/viewforum.php?f=2&sid=ce0b108d1d3a3ac03ae82d0fed8389e3
>>
> 
> 
> Well, that doesn't give any really usefull information to help find the
> issue. It seems quite sepcific on some setups (contrary to what you seem
> to think, we test our release at least a bit before releasing them...)

Hmmm. My DVDs store several bits, though . . ..  Just kidding.

> 
> Could you please tell us what CPU you have on this comuter, the CPU
> usage when the problem occur and copy here the content of the
> View->message dialog ?
> 
> Thanks
> 

The computer is a Dell Optiplex GX260 with 2 GHz Pentium and 256 Megs
RAM.  Almost 2 Gigs swap space.  It is permanently offline and not
networked.  It is quiet during these tests with about 1/2 of
RAM allocated.  Radeon VE graphics (4x AGP); 1280 x 1024 screen res.

Testing with Godzilla DVD (ALL movie DVD's seem to show the
problem):

CPU usage during DVD simple averages around 25%
(Task Mger; high refresh rate, watching graph), ranging from
5% to 30%.  There are no halts; DVD accesses occur at
about 5/s.

CPU usage during DVD menu jerky playing averages about twice
as for simple, with more spread between user & kernel CPU time.
The halts occur at the same frequency (about 2/s) as the DVD
activity light.

My guess is either a buffering or cacheing problem, or a
menu-polling loop somewhere in VLC.  Maybe someone left a
dtor empty somewhere?

Because PowerDVD (which came with the computer) doesn't
jerk with menus, I think a hardware deficiency is eliminated.
-- 
                          John
                      jwill at isp.com
                   John Michael Williams

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