DVD Play Speed

[Mark Knecht]

On Wed, 16 Feb 2005 13:57:53 -0700 (MST), karlp at ourldsfamily.com
<karlp at ourldsfamily.com> wrote:
> RH v8, Intel system (on a slower AMD system this isn't an issue)
> 
> If I play a DVD on my DVD drive (/dev/cdrom1), it's choppy and uneven
> whether I play it with gmplayer or ogle.
> 
> If I
> 
> dd if=/dev/dvd of=file.iso
> 
> then play it using either, it plays nicely.
> 
> Is there a problem with the IDE drivers? I have a scsi disk as the primary
> drive. So, I copied it to an IDE drive on the same system and it still
> played fine.
> 
> Any suggestions might be useful, if I can understand them, or even
> implement them.
> 
> Karl

Karl,
   Is DMA enabled for the DVD? 

[root at Godzilla root]# hdparm /dev/hdd
 
/dev/hdd:
 HDIO_GET_MULTCOUNT failed: Invalid argument
 IO_support   =  1 (32-bit)
 unmaskirq    =  1 (on)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    = 256 (on)
 HDIO_GETGEO failed: Invalid argument
[root at Godzilla root]#

If your DVD happens to be a slave device on an EIDE cable that has
another active device that can slow you down also. I think this
probably isn't a problem since you're using SCSI.

Other possibilities (unlikely) might be that your EIDE controller is
sharing an interrupt with some other device and that other device is
doing strange things. 'cat /proc/interrupts' to take a quick look at
that. It's unlikely since most systems do not share the EIDE
interrupts with other devices.

Hope this helps,
Mark