I’m trying to use my laptops with an external monitor. ThinkPad T60 with Mobility Radeon X1300, and Slackware 13.0 works flawlessly. Unfortunately I encountered problems concerning ThinkPad T40 with Radeon Mobility 7500, Slackware 13.0, and Linux Mint 8. I tried to play movies using MPlayer, Xine, and Totem. In all cases I can watch movies on the laptop’s LCD but on the monitor instead of a movie I see blank blue video screen.

I found here an old bug report concerning similar problem. Ubuntu’s users of machines with Radeon 7500 updating systems from Feisty to Gutsy reported problems with playing movies. Some further information I found here.

In the above threads SteveGotthardt and eliza reported that the problem disappears after switching from 16-bit to 24-bit color depth but desperately-trying-to-go-ubuntu reported it doesn’t work for him. User anewguy suggested to run two instances of the same player to test whether it’s an overlay problem and Roy Kimbrell wrote he had to run two different programs to perform that test. User tgwit didn’t encounter any problems with MPlayer and VLC, and solved the problem with Kaffeine changing video driver to xshm.

I tried all these methods. In my case changing color depth from 16-bit to 24-bit helped nothing. I was also unable to run two instances of the same or two different movie players to ensure it’s the overlay problem. I switched Xine to the advanced mode and changed the video driver to xshm but in result the movies don’t play smoothly and pictures are visibly pixelizated. I can also use MPlayer with x11 video driver – it plays movies on the external monitor but doesn’t allow to scale the pictures to full screen. Both these alternatives aren’t satisfactory.

I will be very grateful for every suggestion.

Are you sure the problem is your player? This sounds like something that will have to be fixed at video card driver level.

I. e. you'll apparently need to explicitly switch output from the local LCD display to the attached monitor, and as far as I know this must be done by your graphics card driver, not the player you are using?

According to the information I found this is the problem caused by the video driver and it affects some movie players. The desktop environment and the other programs work well on both internal and external video device. The problem is with movie players. Using Slackware and Linux Mint I switch video output to the external device. In Linux Mint it works out of the box. In Slackware I prepared the script based on the script found here.

Assuming the problem is caused by the video driver there are a few possible ways to solve it:

1. Change the video driver.
2. Alternate xorg.conf file.
3. Find working movie player.
4. Alternate the configuration of the movie player.

As far as I know there isn’t fglrx driver for Radeon 7500 working with new Linux distributions. Changing color depth in xorg.conf failed in my case. So far I tried three movie players – MPlayer and Xine in Slackware and MPlayer and Totem in Linux Mint. Now I intend to try VLC. Changing video driver in Xine to xshm helped a bit though the result isn’t satisfactory.

So I ask for other suggestions.

Update to the first post

According to my tests Xine doesn't play smoothly the movies with external subtitle's files. It seems the program doesn't buffer the subtitles but reads them on the fly and stops displaying video for a fraction of the second when reads each consecutive phrase. So it's Xine feature and it doesn't depend on the video driver.

Problem solved

I installed VLC in Linux Mint. In the default configuration it displays a blue screen on the external monitor. After switching from default video output to X11 it plays movies on the external monitor flawlessly.

In Slackware I installed VLC found here. Alien Bob’s build doesn’t contain all codecs but it’s sufficient for me at the moment. After switching video output to X11 it works well with an external monitor.