[MPlayer-users] Playing QHD (3840x2160) material with mplayer

[Dean S. Messing]

On 11th Apr 2008, Dominik 'Rathann' Mierzejewski wrote:
> > I am trying to play uncompressed rgb QHD material with mplayer.  After
> > modifying transcode to handle QHD, I was able to generate an .avi from
> > the .png frames of the video.  I can play them with mplayer using 
> > "-vo x11" but only at about 14fps.  I need to play at 24fps.
> > 
> > When I use the xv output driver, I get the Transcript below.  Is it
> > straightforward to increase the accepted dimensions of the xv output
> > driver in the mplayer source code?
> 
> It's not a limitation of MPlayer. It's a limitation of the driver for your
> graphics card or even a limitation of the card itself (video overlay size).
> 
> You could try using -vo gl:yuv=X with various X values or -vo xvidix (see
> man mplayer), but there are other limiting factors as well. I mean, we're
> talking 4.7Gbps (570MB/s) of data here. A decent PCIe 2.0 card can handle
> that (even with one lane), but the limiting factor is the storage. So
> unless you're playing from a RAM disk or a 10Gb network (even an SSD drive
> is too slow), you won't be able to play it in real time. And I'm not
> counting the decoding time here.

Thanks for your response.  I must admit here that I am not very
knowledgeable about video hardware, overlay, or drivers so please
bear with possible silly questions, comments.

First, I _am_ willing to play from RAM.  See below.

You say it might be a limitation of the card.  How then does the card
play using the "-vo x11"? (I'm not challenging you, just trying to
learn.)  Is there a way to see if it is the nVidia driver? (see
below).

I will read up on -vo xvidix, try your suggest, and report back.

Some system facts:

The QHD display is a 60 fps panel.

The card is an nVidia Quadro FX 5500 PCIe x16 card.
(Dual, dual-link DVI, both of which are used to drive the display).

The driver is nVidia's closed source driver. I hear boos from the
audience: sorry, it was necessary to use nVidia's driver because I
needed the TwinView mode to drive the display.  The configuration and
X modeline was worked out (with great effort) by others and is the
only combination currently known to drive this display at 60FPS under
Linux.

The system is a Dell Precision 690 64-bit workstation with 4 Gigs of
ram and a dual-core Xeon 2GHz processor.  The RAID 0 SCSI disks are
fast but not fast enough to play QHD video from disk, so we assume
that the video is entirely held in memory.  We're talking 5 second
clips, (about 3GB), though we can buy both more memory and a second
processor if needed.

I am running Fedora 6 using a 64-bit version of Mplayer:
mplayer-1.0-0.73.20070612svn.lvn6.x86_64

Question: can this system, in principle, drive the display at 24fps?
At 60fps?  I believe the answer to be "yes" to both questions.

Can mplayer do it?  Currently, the system easily plays full-hd
(1920x1080) uncompressed RGB at 60fps using the x11 driver.  The two
CPUs sit at about 40%.  Interestingly, using the xv driver, the usage
is quite a bit higher.

Can I overcome my problems by doing some mild compression of some
sort.  It is important that no artifacts be introduced by the
compression so I'd have to encode at quite a high bitrate.  Not sure
if this can even be done with mencoder or transcode.

Thanks for your help.
Dean