[K12OSN] Pixelation with MPlayer

Mon Mar 5 19:01:32 UTC 2007

Actually, the full-screen bit is where your video chipset takes over. 
Decompressing the video stream from, say, MPEG1/2/4, etc., does use the
server CPU, but scaling the video, once decompressed, is a function of
the video board.  Pop in the right device driver, and your teachers
should be happy.

Please, keep us updated!

--TP
_______________________________
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Microsoft Free since 2003 <http://www.gnu.org/>--the ultimate antivirus
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David Hopkins wrote:
> I also just noticed from the LTSP wiki that my particular mb's don't
> necessarily get the correct configuration for the video chipset.  I
> have min-itx based systems with VIA, so I will try adding the XSERVER
> = via line and see what happens.
>
> Of course, all the teachers want to run at full screen on the systems
> which is 1024x768 and I am not sure what that is going to do to the
> server. :(
>
> Thanks for all the great info.
>
> Sincerely,
> Dave Hopkins
>
>
> On 3/5/07, *"Terrell Prudé Jr."* <microman at cmosnetworks.com
> <mailto:microman at cmosnetworks.com>> wrote:
>
>     Yes, it sure could.  I saw that 90-client-per-server figure and
>     went, "WHOA!!!"  I did some server CPU tests on my own server, and
>     here's what I found:
>
>     640x480 MPEG4 clip:  21% CPU/session
>     320x240 MPEG4 clip:  7% CPU/session
>
>     The CPU's are 1.2GHz Athlon MP's.  This is per CPU core, BTW, so
>     if you've got four such cores, you get just under 4x the capacity.
>
>     --TP
>     _______________________________
>     Do you GNU!?
>     Microsoft Free since 2003 <http://www.gnu.org/>--the ultimate
>     antivirus protection!
>
>
>     Petre Scheie wrote:
>>     Could this be an issue of quantity?  That is, Terrel, how many
>>     clients have you got simultaneously watching the videos?  If
>>     Jim's got an average of 90 clients per server, even though
>>     they're big boxes (I've seen 'em), might that number be more than
>>     the server can handle for video?
>>
>>     Petre
>>
>>     Terrell Prudé Jr. wrote:
>>>     I've watched 640x480 videos (MPEG4) without any problems on my
>>>     thin client with MPlayer.  The key was to swap the video board
>>>     in the thin client for something a bit more powerful.  In my
>>>     case, it was the Matrox Millenium G400; doing that solved all my
>>>     MPlayer issues.  It also, BTW, made TuxType play faster.  Heck,
>>>     I'm able to watch Tom's Hardware videos, in MPEG4, at 720x480,
>>>     without any framedrops, pixelations, whatever--just nice, smooth
>>>     video.  No, I don't have to throw the -framedrop switch, either.
>>>
>>>     Folks, watching videos on thin clients WORKS FINE.  I do it all
>>>     the time.  If you can, please try swapping your video board and
>>>     see what happens.
>>>
>>>     --TP
>>>     _______________________________
>>>     Do you GNU!?
>>>     Microsoft Free since 2003 <http://www.gnu.org/>--the ultimate
>>>     antivirus protection!
>>>
>>>
>>>     David Hopkins wrote:
>>>>     Didn't mean for this to cause problems, so to speak, but ...
>>>>     what I have observed is that the video clip is mostly watchable
>>>>     at the 320x240 resolution that seems to be the 'native'
>>>>     resolution of the clip.  However, it pixelates which is where
>>>>     the teachers start chiming in about the inferior quality.  It
>>>>     does get worse as the clips get larger:  A 5Mb clip and an
>>>>     'extended' version of the clip that is 13Mb do not have the
>>>>     same playback characteristics, with the larger and longer clip
>>>>     looking worse.
>>>>
>>>>     My clients consist of Epia 533-based systems and donated Compaq
>>>>     EN SFF systems.  Either can play back without issues as long as
>>>>     they are fat clients. I have Gb from the server to the switch
>>>>     and 100Mb to the clients.
>>>>
>>>>      If I specify using X11-only, then MPlayer says that the Compaq
>>>>     does not have the resources to play back the video.  Using Xv,
>>>>     it does but is pixelated on fast motion scenes. :(
>>>>
>>>>     MPlayer has alot of options for framedropping, lower fps
>>>>     playback, etc, and I will try and play with these to see if
>>>>     there is some magic combination that provides overall better
>>>>     quality.
>>>>
>>>>     I really hope that the Atlanta work goes well since it will
>>>>     help me when I periodically try to the the State of Delaware
>>>>     DOE interested in the thin client approach.  I have a few Reps
>>>>     and Senators that know about the option, but getting them to
>>>>     commit time to really looking at it has been tough and little
>>>>     glitches like lower quality movie playback seems to 'impress'
>>>>     them more than the phenomenal uptime of the systems, ease of
>>>>     use, ease of management, etc.
>>>>
>>>>     Slightly off-topic, but the same instuctor that is really vocal
>>>>     about the playback also was vocal about not getting sound on a
>>>>     video clip a few weeks back.  After playing it back in a pure
>>>>     Windows environment, it was finally possible to convince him
>>>>     that the clip in question didn't, in fact, have any sound and
>>>>     was only video.
>>>>
>>>>     Sincerely,
>>>>     Dave Hopkins
>>>>
>>>>
>>>>
>>>>     ------------------------------------------------------------------------
>>>>
>>>>
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>>>
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