Video playback on Linux

DVD and video playback on Linux File:Screenshot xine.png My latest adventure had involved getting video and dvd playback from Debian (Sarge) and Fedora Core 1. With Debian, getting xine installed was as easy as apt-get install xine-ui, because apt-get took care of the dependencies (namely xine lib). Once xine was installed, I found a neat site about xine in general, and found out that you can install various skins for the xine player user interface (the picture shows Celoma Gold). To download a new skin, you press Ctrl+d while window focus is on the Xine application. You should definately visit http://cambuca.ldhs.cetuc.puc-rio.br/xine/ for instructions on how to get xine, and how to get various codecs to support Windows and Mov file formats.

Of course, once xine was installed, I found out quickly that I could not access my CD-R drive, or my external DVD drive. I would get an error to the effect that "only root could mount dev/scd0 on mnt/dvdram". I was pretty sure that when I installed Debian on my system originally that I had chosen to allow normal users to mount devices (like floppy, cd-writer, dvd) -- mostly because this is my computer and I want to do what I want without having to invoke special super-user privileges. Also, this is what I'm accustomed to doing in a Windows environment. I think it is great that Linux allows you to precisely configure access to various resources, but for a desktop system, this feature can get in the way. So, I went hunting for the proper way to turn these devices on.

ls -al /mnt

showed that there was indeed a mount point defined called /mnt/dvdram. I tried to change the ownership of the mount point

 chown greg:greg /mnt/dvdram

but that didn't work

ls -al /dev/scd0

showed that the device was owned by root, and the group cdrom. I checked into the group to see if I was a member by using the graphical tool kuser (System -> User Manager). That showed I was a member of the cdrom group and the floppy group.

brw-rw-rw-    1 root     cdrom     11,   0 May 20 21:22 /dev/scd0

I read somewhere that I should do a 'modprobe ide-scsi' which didn't show any results. The next command I found was

cdrecord -scanbus

which did show that my DVD drive was there, and also my scanner. I made sure the device was indeed mounted on the /mnt/dvdram mountpoint

mount /dev/scd0 /mnt/dvdram

and, since Xine looks for DVDs at /dev/dvd by default, I created a symbolic link from /dev/dvd to the existing /dev/scd0

ln -s /dev/scd0 /dev/dvd

I also read that you need to have mtrr compiled into your kernel, which you can tell by this command

cat /proc/mtrr

According to this article, http://linux.omnipotent.net/article.php?article_id=11799, you need DMA (Direct Memory Addressing) enabled on the drive in order to avoid jumpy playback.

hdparm -d /dev/dvd

Told me I didn't have the hdparm tool, which I confirmed with a

locate hdparm

So, I installed hdparm

apt-get install hdparm

But now, when I run the same command, it tells me that this operation is not allowed on a SCSI drive. As far as I know, this is not a scsi drive, but an ide drive using scsi emulation...Then again, I just a user, and I'm feeling pretty lucky that I know it's a DVD drive. So, I'm not sure how to cure my jumpy playback issues. Anyway, at least I've got the permission problems licked, and Xine is installed with a nice UI, and I can playback a DVD from my external DVD drive.