32-Bit Graphics Driver

Although 32-bit distributions mostly play Silverlight videos smoothly, you might experience dropouts in the playback with a 64-bit Linux. The problems with 64-bit support are caused by the fact that the 32-bit Silverlight requires a 32-bit graphics card driver.

The setup routines for installing of most distributions will not install this 32-bit driver out the box. You can tell that the driver is missing from the error messages of the Pipelight plugin when you start the browser in a terminal. Listing 7 shows the output for a system with an Intel graphics card.

On Debian and Ubuntu, you can configure the 32-bit drivers by installing the libgl1-mesa-dri:i386 package. On Ubuntu 12.04, install libgl1-mesa-dri-lts-saucy:i386 (Listing 8). Although the libgl1-mesa-dri:i386 package is available on Ubuntu 12.04, it removes the entire X server – so do be careful. Under Arch Linux, you need to specifically install the driver required for your system (Listing 9). Look online for additional information on 32-bit drivers with Pipelight [13].

Optimizing Pulseaudio

The PulseAudio sound server used in many Linux distributions can also cause problems with services that require Pipelight and Silverlight.

Misfires occur if the sound server fails to keep up with the sound. This problem is not limited to older systems with slow CPUs: I simulated the problem on a computer with a recent Core i7 quad-core CPU (3GHz).

You can usually solve these PulseAudio problems with a smaller packet size. To change the packet size, open the PulseAudio configuration file, /etc/pulse/daemon.conf, as root in your favorite editor, and edit the following default-fragment-size-msec (Listing 10).

The default value is 25; I changed this value to 5, and a Silverlight-based video ran at 25 fps without any jerkiness in the image and sound. To enable the new settings, you should save the configuration file and restart PulseAudio using the pulseaudio -k command.

Conclusions

In my tests, I was able to successfully use several popular video-on-demand services in Linux. Only Sky Go turned out to be really awkward because I had to change the configuration to force the system to use Silverlight 5.0. Future versions of Pipelight will do a better job of supporting the more advanced encryption in Silverlight Version 5.1. Note that some of the hurdles are legal, because many of the problems with Silverlight 5.1 support are related to DRM. The Magine and Watchever services turned out to be particularly Linux friendly and did not even force me to spoof a Windows user agent.

I discovered one annoying limitation with Amazon Prime Instant Video: Amazon's online video library only plays movies in SD quality with Pipelight under Linux; the Amazon player refuses to play HD videos, claiming that the monitor lacks HDCP support [14]. (See the "HDCP" box.) The reason for this problem is that the Linux graphics drivers do not support functions for restricting the user, but Amazon's service requires mandatory digital rights restrictions. The Pipelight team is working on an appropriate workaround.

Many Rasp Pi fans use the tiny computer as a media center. Raspbmc and OpenELEC are two distributions that specialize in optimizing XBMC for the capabilities of the Rasp Pi. In theory, a Raspberry Pi media center would be an ideal use for Pipelight; however, Silverlight is only available for x86 instruction sets, so the Silverlight plugin won't work with the ARM-based Raspberry Pi.