Windows 8 Video app may experience performance issues when software decoding is used

Applies to: Windows 8Windows 8 NWindows 8 Pro More

Symptoms


Consider the following scenario:

  • You are running Windows 8 or 8.1.
  • You use the Video app (Xbox Video) in Windows 8 to play a video that is on your computer.
  • The encoded video format is not supported by the graphics hardware decoder and software decoding is used instead.

In this scenario, during playback you may encounter video stuttering or dropped frames. The same video may play without any issues when using Windows Media Player.


Cause


If a video is encoded in a format not supported by a video card hardware decoder, Windows uses a software decoder to render the video. In this scenario, if the machine has insufficient CPU resources to decode the video in realtime, you may encounter video performance issues during playback in the Windows 8 Video app. The audio plays correctly and a low video framerate can be observed.


Resolution


A system may have insufficient CPU resources if the power profile in Windows is set too aggressively in terms of power saving. For example, a PC may have a maximum processor state of 50% while on battery and 60% when plugged in. To provide additional CPU performance, these values can be increased. Changes to the maximum processor state can made using the steps below.

  1. In Windows 8, use the keyboard shortcut of Windows Key+X to bring up the quick link menu and select Control Panel.
  2. In the Search pane, type in "Power" without the quotes.
  3. From the search results, click on "Edit power plan".
  4. Clink on "Change advanced power settings".
  5. From the list of advanced settings, find and click on the one named "Processor power management".
  6. Open the "Maximum processor state, where the maximum processor state setting can be changed for battery or while plugged in. As an example, you could change the value while plugged in to 100%.
Note: You may need to be logged in as an Administrator to make changes to this setting. In addition, this specific setting may not be available on all machines.


More Information


Microsoft Store applications (including Xbox Video) use more CPU resources due to the enhanced UI. If a machine is just under the required CPU performance, Xbox Video may have a performance issue but Windows Media Player may successfully handle playback.

The MPEG4 Part 2 format is one format known to not be supported for hardware decoding by various video card vendors. When the software decoder is used, video is displayed in I-Frame only mode. The low 'I-Frame only mode' frame rate for MPEG4 Part 2 content is due to the overly aggressive handling of quality messages (QM). It takes only 4-5 frames to be late to get in to I-Frame only mode and it takes 4-5 I-Frames to get out of this mode. Microsoft is reviewing the aggressiveness applied in this situation.