Revision as of 06:26, 19 February 2009

General

What is it

The API is called VDPAU (Video Decode and Presentation API for Unix). It provides a large subset of PureVideo HD functionality for NVIDIA Linux, Solaris, and FreeBSD users. It in essence provides what PureVideo/DirectX Video Acceleration is on the Windows platform

Some highlights of VDPAU:

• Defines an API for GPU-accelerated decode of MPEG-1, MPEG-2, H.264, and VC-1 bitstreams.
• Defines an API for post-processing of decoded video, including temporal and spatial deinterlacing, inverse telecine, and noise reduction.
• Defines an API for timestamp-based presentation of final video frames.
• Defines an API for compositing sub-picture, on-screen display, and other UI elements.

Note that VDPAU does not address content protection issues.

Some highlights/limitations of NVIDIA's current implementation:

• Supported on NVIDIA GPUs with the NVIDIA second generation video processors (see list further below)
• Currently, only one video stream can be decoded at a time; we hope to lift this restriction eventually.

Nvidia Implementation

The current API documentation is here.

The most recent driver release may be obtained here here

The VDPAU support in the NVIDIA 180.06 beta release is still very preliminary. We are aware of cases of visual corruption and in some cases GPU hangs. We will be working on these issues over the next several NVIDIA driver releases.

While NVIDIA's VDPAU implementation is not ready for end user use yet, it should be far enough along that interested application developers can begin working with it.

If other hardware vendors are interested, they are welcome to also provide implementations of VDPAU. The VDPAU API was designed to allow a vendor backend to be selected at run time.

ffmpeg + mplayer

NVIDIA has developed patches to ffmpeg and MPlayer to demonstrate a video player using VDPAU. These patches have been integrated to the main line and include changes against libavcodec, libavutil, ffmpeg, and MPlayer itself; they may serve as an example of how to use VDPAU.

Supported Cards

VDPAU is currently supported on the following NVIDIA GPUs (as at version 180.16 released December 12, 2008)

VC-1 support in NVIDIA's VDPAU implementation currently requires GeForce 9300 GS, GeForce 9200M GS, GeForce 9300M GS, or GeForce 9300M GS or 9400/9300 IGP. VC-1 is an alternative to H.264, and is a supported video codec for HD DVDs and Blu-ray Discs.

Support for the following GPUs was added with the stable driver version 180.22:

• Quadro FX 2700M
• GeForce 9400M G
• GeForce 9400M
• GeForce 9800 GT
• GeForce 8200M G
• GeForce Go 7700
• GeForce 9800M GTX
• GeForce 9800M GT
• GeForce 9800M GS
• GeForce 9500 GT
• GeForce 9700M GT
• GeForce 9650M GT
• GeForce 9500 GT

Supported Drivers

Support started with version 180.06. Most recent current version is 180.22 marked as Stable, released January 8, 2009. The VDPAU API changes in this version and programs must be recompiled to utilize the driver. Beta drivers can be found at download.nvidia.com under the Linux-* folders.

New Pre-release drivers 180.27 released 29th of January 2009 incorporate a lot of fixes to VDPAU. 32bit 64bit

Newer Pre-released drivers 180.29 released 6 Feb 2009 are available here 32bit 64bit

MythTV Support

VDPAU was announced to the MythTV developer mailing list on Nov 15, by Andy Ritger, Manager of the NVIDIA Linux driver. Within four days, Issac had posted a POC (proof of concept) patch against the upcoming 0.22 TRUNK line for VDPAU support, saying "Preliminarily, this stuff looks _very_ promising." On November 29, Changeset 19165 included preliminary support within TRUNK. While VDPAU support is still in it's infancy of both the driver and MythTV, several testers have responded that they are able to use VDPAU with some issues. Currently running trunk with VDPAU support not explicitly recommended, except for testing and bug reporting purposes.

What works?

• Deinterlacing (select "Advanced (2x, Hw)" for best results)
• OSD/PiP.
• Color controls
• Other stuff

What doesn't?

• Lots and lots of other stuff.

MythTV 0.21-fixes and Ubuntu repository

Jean-Yves Avenard has posted a patch for MythTV 0.21-fixes (19823) on his site that backported VDPAU from the development branch. He also provided a Ubuntu/Mythbuntu repository for all of us running that distribution. MythTV and mplayer with VDPAU support can be yours by using this repository. Add to /etc/apt/sources.list:

   deb http://www.avenard.org/files/ubuntu-repos files/

In addition to "aptitude safe-upgrade", the package nvidia-glx-180 needs to be installed to replace the earlier version of nvidia-glx-*.

Display Profiles

Setup a display profile with:

   decoder = nvidia vdpau acceleration
   video + osd renderers: vdpau 

and a second recommended as a fallback:

   decoder = ffmpeg (Standard)
   video + osd renderers: vdpau

Issac suggests to make sure composite extension is disabled when using vdpau (in xorg.conf):

Section "Extensions"
      Option  "Composite"     "Disable"
EndSection

Compiling MythTV with VDPAU

For Myth to support VDPAU it must be built in. MythTV's compilation script supports this. To enable it use the configure script and the --enable-vdpau option.

The following is an example of how to compile MythTV with VDPAU:

MythTV

  ./configure --prefix=/usr --enable-proc-opt --disable-joystick-menu \
  --disable-firewire --disable-hdhomerun --disable-xvmcw --enable-xvmc-opengl \ 
  --enable-vdpau  --disable-directfb --enable-opengl-vsync

MythPlugins

  ./configure --prefix=/usr --enable-opengl --enable-mytharchive \ 
  --disable-mythbrowser --disable-mythcontrols --disable-mythflix \ 
  --enable-mythgallery --disable-mythgame --enable-mythmusic --disable-mythnews \
  --disable-mythphone --enable-mythvideo --disable-mythweather \
  --disable-mythzoneminder --disable-mythmovies

Caveats

• No AGP cards support this feature (But PCI versions exist)
• Currently only supported by the developers in SVN 0.22 TRUNK. The backport to 0.21-fixes is unsupported.
• Warning: Do not install the vdpau beta driver unless you intend to use an NVidia-based video cards exclusively thereafter. Merely installing the nvidia driver breaks digital playback on Intel (and probably any other) video/graphics cards. The nvidia installer *replaces* standard header files (/usr/include/glext.h, glext.h,glxext.h and glx.h) and library files (/usr/lib/libGLcore.so, libGL,so, libGLU.so and libGL.la), with nvidia specific versions which breaks OpenGL playback on other graphic cards. (The 180 series drivers do appear to be usable with non-vdpau capable nvidia GPUs (6200 etc.))
• If you wish to try an nvidia video board instead of your other video/graphic chipset, be careful. Make a mythconverg database backup, and note the SVN of your present working version. In addition, it would be wise to extract the NVidia pkg.run file (NVIDIA-LINUX....pkg.run -x) and make backups of the original files for which copies exist in the ../include/GL, ../lib and ../X11R6 folders. The package help states that the option '--no-opengl-headers' will skip installing the Nvidia OpenGL headers, however it appears that the other libraries will be replaced anyway. It also does not appear to be the case that the '--uninstall' option actually reverses the install, as the orginal files do not appear to be retained. This is a real time-killer ( and WAF killer) and may require a complete re-installation of the system if you wish to revert to a different family of GPU chip.
• Video profiles can not filter based on video format (only by resolution). So if you wanted to use VDPAU for H.264/HD-PVR and Xv for Mpeg2 this is not currently possible.
• Off loading to the GPU may increase its heat out-put. It may seem obvious, but check your GPU temperature and cooling arrangements.

Troubleshooting

The following configuration changes should be used to prevent issues with VDPAU when used with MythTV:

To prevent vertical and horizontal tearing of the image when viewing live tv or recordings, run the following to disable X Composite Extension (may also cure the all white/gray OSD):

   sudo nvidia-xconfig --no-composite

• Enable OpenGL VSync within MythTV.

Links to further information

NVIDIA Linux Forum - http://www.nvnews.net/vbulletin/forumdisplay.php?f=14

NVIDIA Component Out MythTV Wiki Page - NVIDIA_Component_Out

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