[mythtv-users] What is HW XVMC MPEG DECODING

[Ryan Allen]

Thanks Thomas,

    This is really good information.  Hopefully, this blurb will soon
    show up in google searches!

    -- Ryan


* Thomas M. Pluth <tpluth at surewest.net> wrote on [06-21-04y 22:20]:
> XVMC stands for X Video Motion Compensation.  It's one of the two forms of
> video acceleration that the Nvidia cards support, the other being IDCT
> (Inverse Direct Cosine Transform).   These two features can offload some of
> the graphics processing from your CPU to the GPU on your video card.  I
> believe the Intel Extreme Graphics (845, 865 and 875 chipsets) also support
> XvMC with the xorg driver (i830), but I haven't tried it.   
> 
> MythTV supports the use of XVMC on cards that support it, if Myth is
> compiled with XvMC support and the correct libraries are linked in.   I've
> played with it some, but unfortunately, the Nvidia drivers are not quite up
> to the task of accelerating HDTV output just yet.  They don't support
> interlaced output and scaling from one resolultion to another doesn't seem
> to work quite right yet, either.  Another problem with using XvMC is that
> the OSD in MythTV causes stuttering of the picture. 
> 
> It definitely helps offload processing for DVD resolution (720x480), and
> with any luck Nvidia will get their drivers tweaked to work better at
> 1280x720p and/or 1920x1080i with the next release (whenever that is).
> 
> -----Original Message-----
> From: mythtv-users-bounces at mythtv.org
> [mailto:mythtv-users-bounces at mythtv.org] On Behalf Of Ryan Allen
> Sent: Monday, June 21, 2004 2:33 PM
> To: Discussion about mythtv
> Subject: [mythtv-users] What is HW XVMC MPEG DECODING
> 
> In my previous posts, I fixed my no sound from TV and recordings problem
> by disabling this.  When I installed knoppMyth last week, I choose the
> "lx" option, which installed drivers for the LIRC and XVMC.  I searched
> and scoured the Internet until I finally found a spec sheet for the
> nForce chipset (gForce 4 on my motherboard) and it said it supported
> "XVMC".  So I installed it.  However I still have no idea what it is.
> 
> Can somebody fill us in?  Thanks,
> 
>     -- Ryan
> 
> 
> 

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