Poor Performance

[Jean-Paul Saman]

Jason Bradley Nance wrote:
> 
> Hello everyone.
>      I just downloaded and installed vlc.  I tried installing from both
> the Red Hat RPM and from source to see if I could get some better
> optimizations, but both have yielded the same results.  I also read what
> there is of docs.
>      I am running Red Hat 7.1 on a PIII 600 with 256 MB RAM and a 32 MB
> nVidia TNT2, yet the DVDs do not play at a watchable rate (sometimes not
> at all).  I have a DVD decoder card for my drive, but I can't find in
> the docs what plugin to load or even how to load it.
>     I am thinking that maybe my problem is the lack of support for my
> sound card (a Turtle Beach Montego II Quadzilla (Vortex 2 chipset) from
> experience with other players (Xine, OMS), the the quality is much lower
> than I expected.
> 
try to run vlc like this:

vlc --yuv yuv --overlay -I gnome -V sdl

It gives enough performance for me on PIII 750. Especially the SDL
libraries will help in performance. If that is not enough, then try
tweaking your hardisk paramaters to optimize for sequenctial access of
you dvd drive. Let's assume that your dvd drive is /dev/hdc. Then do:

/sbin/hdparm /dev/hdc

This will tell you what settings /dev/hdc/ can accept, then play with
some settings for optimal performance. For me these things worked.

/sbin/hdparm -A1c1d1u1a128 /dev/hdc

Legenda:
 A1 tell drive to lookahead
 c1 tell drive to use 32 bit access to main memmory
 d1 tell drive to use dma, this is crucial to releave the processor from
some burdens of moving memory around.
 u1 tell drive to use unmasking irq's, this will ensure you're
throughput from the drive. It can not be interrrupted when it is in an
IRQ handler.
 a128 tells drive to read ahead 128 blocks (64 usually gives enough
performance). This setting only makes sense when you know youre only
reading the drive sequentially. Usually this is the case when you're
playing a dvd. 

Carefully try this out, because you're tweaking the drives behaviour. I
used this tweaking on a 233 MMX pentium that serves as dvd server. It
pushes a DVD stream with 6-7 Mbps over a 10MB LAN network (I used vlms)
and it gave me enough performance to view a DVD. 

Good luck,


Greetings,
Jean-Paul Saman