Playback profiles are a way for MythTV to set individual playback settings for various types of media through the internal media player.
Six "default" Playback Profile Groups are automatically available in MythTV. These profile groups have the names Slim, Normal, High Quality, CPU--, CPU+, and CPU++. While you may edit these default profile groups, generally it's better to think of them purely as examples and either use them without modification or create your own playback profile group if you wish to edit and modify settings. This also has the benefit of allowing you to start with a simple configuration (i.e. if rez > 0 0 -> ffmpeg & XVideo) and experiment by changing items (OSD renderer, OSD fade, deinterlacers, ...) individually and seeing how the change affects playback quality and performance. Then, as you determine how the settings affect your system, you can add complexity to get exactly the behavior you want for each type of video you use.
If you have not yet modified your playback profile configuration, the "Normal" playback profile group will be selected by default. To use a profile group that is similar to the software-rendered (no XvMC/no PVR-350 decoder) settings in versions before 0.21, choose "Slim."
Each playback profile group consists of multiple profiles that are applied according to priority and match criteria (currently matching the recording's source resolution to some specified resolution). The profiles will be evaluated in order of priority, then by matching resolutions, but will only be used if the decoder is supported on the current hardware/configuration. In other words, if you have ivtv specified as the decoder, but don't have a PVR-350 configured, the ivtv profile will be skipped in favor of the next matching profile. Likewise, XvMC only supports MPEG-2 streams, so if you wish to use XvMC profiles, they should be higher priority than Xv profiles (which can be used with both MPEG-2 and MPEG-4), so MPEG-4 recordings will fail through the XvMC proflies but MPEG-2 streams will be caught by the higher priority XvMC profile.
What options you have for each setting is defined by your configuration options as well as which development packages you have installed on your computer. The available settings are briefly as follows:
- Resolution comparison
- These settings define the resolutions that this group will apply to.
- This defines what library will assist MythTV in displaying the image, be it software (nuppeldecoder, ffmpeg, libmpeg2), or hardware assisted (ivtv/pvr350, xvmc, mac, via-xvmc)
- Video Renderer
- This controls how the video is actually displayed to the screen, and is defined by what's available to you
- OSD Renderer
- How the OSD is overlaid on the video
- OSD Fade
- Whether the OSD fades or vanishes when it times out
- The method used to deinterlace the video for display
- Secondary Deinterlacer
- The method used if the first method fails. For example, if the framerate is too slow for the bob deinterlacing method
- Filters ; The filters to apply
Default profile groups
Note: If you manage to muck up your playback profile groups and want the defaults back: First, copy down information you want to "save" from your current Playback Profile Group configuration (unless you want to just start over). Then, start deleting all the Playback Profile Groups. Go to the "Delete" button next to "Current Video Playback Profile" and hit it until there's no name left in the drop-down box next to "Current Video Playback Profile" (it should be blank). At this point, the Playback Profile Entries may look messed up (there may be some seemingly random number of them that may or may not be filled out), but don't worry about that. Then, select the Next button to "save" your settings. Finally, go back through TV Setting->Playback until you get to the "Playback Profiles (3/9)" page, where you'll see all the defaults. Then, add a new playback profile group and edit to your content.
CPU++ default settings
|CPU ++||Profile 1||Profile 2|
|Description||ffmpeg with xv-blit||ffmpeg with quartz-blit|
|Resolution||> 0 0||> 0 0|
CPU+ default settings
CPU+ is a profile group designed to offload as much work as possible to the hardware.
|CPU +||Profile 1||Profile 2||Profile 3||Profile 4||Profile 5|
|Description||ffmpeg||XvMC for high resolution||libmpeg2 fallback for high resolution||XvMC for mpeg2||libmpeg2 fallback for mpeg2|
|Resolution||<= 720 576 and > 0 0||<= 1280 720 and > 720 576||<= 1280 720 and > 720 576||> 0 0||> 0 0|
CPU-- default settings
CPU-- is a profile group designed to offload as much of the work as possible into hardware.
|CPU --||Profile 1||Profile 2||Profile 3||Profile 4||Profile 5|
|Description||ivtv (PVR-350) if available||XvMC for lower resolutions||XvMC for higher resolutions||XvMC for mpeg-2||libmpeg2 fallback|
|Resolution||<= 720 576 and > 0 0||<= 720 576 and > 0 0||<= 1280 720 and > 720 576||> 0 0||> 0 0|