DVD stutters...

[mick]

after just 'happening' on a fix for my DVD player to run in xine (apt-get install libdvdcss2) on the Mepis Linux site, I tried it in Knoppix (another Debian...) and sho' nuff, it works! but the image stutters, hitches, hiccups a bit (can you tell I really don't know how to describe this?) It's like really bad streaming video from the 'net...

Any ideas on how to even this out; make it smoother?

[m_yates]

You need to enable DMA on your dvd drive. For example, if your dvd drive is hdc:

hdparm -v /dev/hdc

will tell you if DMA is on.

hdparm -d 1 /dev/hdc

will turn on DMA.

To enable DMA at boot time:

apt-get install hwtools

kwrite /etc/init.d/hwtools

Add this line just above "true" under "hdparm optimization":

hdparm -d 1 /dev/hdc

The above command will then be run to turn on DMA during boot up. There is probably a better way to turn on at boot time, but the above works.

[mick]

That has done the trick!

Thanks so much for that INCREDIBLY speedy reply!

Mick

[mick]

I spoke too soon...

That works great to get DMA enabled while Knoppix is running, but the enabling at boot time didn't seem to 'take' (even after rebooting)

Did I miss something that I could have done during install?

[Stephen]

I spoke too soon...

That works great to get DMA enabled while Knoppix is running, but the enabling at boot time didn't seem to 'take' (even after rebooting)

Did I miss something that I could have done during install?

If you edited the file suggested above then it was not used when you rebooted. You need to edit either the file /etc/default/hdparm (if still using the older version) or /etc/hdparm.conf and put something like this at the bottom of the file:

/dev/hdc  {
                dma = on
}

I'm not sure if the syntax is correct for the older version it's been a while since the change was made and it seems to have deleted the old one from my install you may want to upgrade the package to the newer version to prevent editing again when the upgrade happens to you eventually anyways.

[m_yates]

It is great to know how to turn on DMA using hdparm.conf.

It is strange that hwtools method doesn't work though. It works for me. I use the standard Knoppix initscripts and the DMA command is run during boot up after installing the hwtools package and editing the hwtools file as described above.

[mick]

Back again -

Well, after much experimentation, I have to admit (sheepishly) that the mistake was not Knoppix - it was me.

When I typed in the changes as per your instructions, I forgot that my DVD is hdd - not hdc (as is yours). When I discovered the problem, retyped and rebooted, Xine played LOTR without a hitch.

Thanks for all of your help

[pau1knopp]

I am having the same problem with a "stuttering DVD". My dvd is /dev/scd0, but when I run this command I get the following error...

root@wally:/debs# hdparm -v /dev/scd0
/dev/scd0 not supported by hdparm

The drive is a compaq IDE dvd drive. Anyone else run into this?

Regards,

~paul

[Stephen]

I am having the same problem with a "stuttering DVD". My dvd is /dev/scd0, but when I run this command I get the following error...

root@wally:/debs# hdparm -v /dev/scd0
/dev/scd0 not supported by hdparm

The drive is a compaq IDE dvd drive. Anyone else run into this?

Regards,

~paul

You do not do it on the scsi emulated device but the /dev/hd? that the device is before the emulation happens then it turns on the dma for you on the drive and it is then continued to be used when the emulation takes place.

[pau1knopp]

Good information...

How do I tell which /dev/hd? I should be using?

tia,

paul