Trouble with DVDs · Aug 16, 23:16 by Shannon Wynter

G’day Folks.

I’m sorry about the box being up and down so much in the past week, I’ve managed to blow up not one, but two PSU’s. I’m on a temporary PSU borrowed from work until my new 550 watt babies arrive on Friday.

I’ve also had problems with DVD’s in this time.

I thought I’d share my experience with you to save you some effort.

The beginning
For a while now, I’ve longed to have a sexy slot-loading USB2 DVD drive for my MythTV box. Well I got one on Tuesday around lunch.

I unplugged the hacked up USB/IDE controller with and pilfered laptop drive that I’d been making do with for a while, and plugged my new baby in. It came straight to life.

Fantastic I thought, raced over to the shelf and grabbed the first DVD I could find, slipped it into the drive and hit “Play DVD” the screen blinked, that was it.

Oh Crap. As this drive is capable of running entirely off the USB power, I thought maybe my board wasn’t capable of supplying enough power (At the time it was probably true – poor 250 watt PSU).

I jumped into dmesg and saw a stack of read errors. Strange I thought…

• Lets throw a regular old CD in. It works, can dd the entire disk into /dev/null without a single error.
• Lets throw a regular old Data DVD in. OMG it also works.
• Lets get daring and try one of those ‘backup video dvds’. Works right off the bat.

Ok, so it’s looking like a CSS/Region issue. (Note the discs I have are Region 2 & 4). I boot the big PC into Windows, plug the drive in and check it out in the system properties. It’s set to region 2.

Well, I’ve come this far, I’ll set it to Australia (Officially PAL region 4).

I take the drive back to the MythTV box and plug it in. Throw the video DVD in and hit play.

I’m greeted with much the same results as last time, ‘blink’. So I go off and check the logs again. Hmm interesting, no errors. Maybe there IS something wrong with the drive?

I boot my big PC back into Linux, and plug the drive in. Fire up xine, and it works.

Crap

• is it something wrong with the mobo on the other box?
• is it something wrong with the power?
• have I managed to kill a library?

Well, to be honest I never addressed the first concern.

I spent most of yesterday re-compiling libdvdcss, xine-lib and xine-ui in various different methods.

The best I could get was

---------------------- (ERROR) ----------------------
The source seems encrypted, and can't be read.
Your DVD is probably crypted. According to your country laws, you can or can't install/use libdvdcss to be able to read this disc, which you bought. (Media stream scrambled/encrypted)

['Encrypted media stream detected' 'Media stream scrambled/encrypted']
------------------ (END OF ERROR) -------------------

And a very useful
xiTK received SIGSEGV signal, RIP.

I brought home the 400 watt PSU today from work to test the power and see if that fixed it. Still no go.

So one last time I recompiled anything that looked like it had anything to do with multi-media. Recompiled my kernel and modules making sure I had everything as similar to my big PC as possible. Re-install all the ALSA bits.

Reboot, try again… ‘blink’

And then

I was looking at the non-debug output of xine where it said that it couldn’t find a map file in .dvdnav – so I did a ls ~/.dvd[tab]; and the only dir that came up was ~/.dvdcss.

Being the curious person I am, I hit enter on it – wow, it’s a directory full of cached CSS keys. Being the destructive person that I am my next action was to rm -fr this directory.

I popped back into MythTV and clicked on the “Play DVD” button… and OMFG it’s working!!!

In closing

Always rm -fr your .dvdcss dir before rebuilding half your box.

Note

I would like to thank google for not having the answers and driving me around in circles.
I would also like to point out that of the 300 such similar threads on the gentoo forums, this was not covered in any of them either.

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