Archive:HOW-TO:Fix common 1080p playback issues

You may find that 1080p videos play back jerkily and/or drop frames. This is mostly a problem on Windows, but sometimes happens on Linux as well. The problem is usually that decoding video is very CPU intensive and unless your PC has a powerful CPU it simply can't keep up with the video and has to drop frames. If you check the CPU usage you'll probably find it is maxed out. This has become a particular issue with the popularity of Nettop and Netbook PCs based on the Intel Atom processor. None of the the Atom range of processors is fast enough to decode 1080p without assistance from hardware acceleration.

Modern video cards have processors that can accelerate video playback, however a standard way of doing this has not emerged yet. Recent nVidia cards have a method of acceleration called VDPAU (see http://en.wikipedia.org/wiki/VDPAU) and XBMC supports this but only on Unix. You should find that with a recent nVidia card XBMC Live and XBMC on Ubuntu will play 1080p quite happily. The Windows version of XBMC v9.11 does not support hardware acceleration, but work is in progress on several fronts. This article describes the various ways you can get 1080p videos to play on Windows.

Update: support for DXVA has been added to the development build of XBMC, and will be in the next version due in May. You can try it out by downloading a recent build from http://mirrors.xbmc.org/. For info on DXVA see http://en.wikipedia.org/wiki/DXVA.

Problems on Linux
We get occasional reports in the forum (http://forum.xbmc.org/) that 1080p won't play on Linux. Assuming you have an nVidia card that supports VDPAU (see the Wikipedia article) try updating the video drivers. Also try switched off all the Gnome desktop visual effects and or compiz.


 * A short How-to for Linux Nvidia playback fixes can be found here. Should work for XBMCbuntu and other variations of Linux.

Windows "Fake full screen" setting
A quick check before you go any further: look in the Settings, System, Video output section and check the Use a fullscreen window rather than true fullscreen setting. If this is enabled try disabling it.

Broadcom Crystal HD
I've put this first as it's currently generating a lot of excitement. The Broadcom Crystal HD is an accelerator card that you can fit into a mini PCIe slot. See http://www.broadcom.com/press/release.php?id=s387278 for details. The accelerator has experimental support in the recent builds of XBMC. It's cheap (around £20 or $30 on ebay) but it does need a PCIe slot and on your Nettop this probably has the wireless card in it. However if you can install a Crystal HD reports in the forum suggest it works very well and allows playback of 1080p even on the humblest of Atom processors.

Update 13th Jan: the Crystal HD only works with the OpenGL build so you'll have to compile your own or try and find somewhere to download an OpenGL build. Having tested the Crystal HD with an OpenGL build on a Revo 3600 (Atom 230 CPU) it plays 1080p perfectly at 25-30% CPU :-)

Use an external player
The module within XBMC that plays videos is called DVDPlayer, and DVDPlayer doesn't support hardware acceleration. However there are some media players that support hardware acceleration on Windows using the DXVA interface (see http://en.wikipedia.org/wiki/DirectX_Video_Acceleration for details of DXVA). One media player that works well is MPC-HC (http://mpc-hc.sourceforge.net/).

XBMC can be configured to use an external player like MPC-HC. When it is configured this way XBMC will play a video by running a copy of MPC-HC then waiting for it to finish. This works pretty well, and most of the time you wouldn't notice that XBMC is using an external player. However it is a bit tricky to configure. The article HOW-TO use an External Player for media playback explains how to configure the external player. If you run into problems ask in the forum as lots of people there use MPC-HC and can help with the configuration.

DSPlayer
The DVDPlayer module built into XBMC doesn't support hardware acceleration on Windows, but there is an experimental video module called DSPlayer that does support DXVA hardware acceleration.

DSPlayer is currently supported in the forum in the thread http://forum.xbmc.org/showthread.php?t=61355. Reports suggest it works well, though it's missing some of the features of DVDPlayer.