[mythtv-users] mpeg2 playback performance issue makes no sense

Michael J. Lynch mlynch at gcom.com
Wed Oct 13 13:50:59 UTC 2004


See comment inline below:

Donavan Stanley wrote:

>On Tue, 12 Oct 2004 11:06:03 -0400, Joseph A. Caputo
><jcaputo1 at comcast.net> wrote:
>  
>
>>On Tuesday 12 October 2004 10:27, Michael J. Lynch wrote:
>>    
>>
>>>Ah ha....See comment below.
>>>
>>>Joseph A. Caputo wrote:
>>>      
>>>
>>>>If you really want to see how Myth's internal player performs,
>>>>instead of trying to trick Myth into playing it as a recorded TV
>>>>program, simply use MythVideo ("Watch Videos").  There is a setup
>>>>option that lets you configure the player command to use for this;
>>>>apparently you have yours configured for mplayer (the default,
>>>>IIRC).  If you change this to "Internal", it will use the internal
>>>>player without the need to fool Myth.
>>>>        
>>>>
>>[snip]
>>    
>>
Ok...so I did this just this morning.  The results are:
    Myth Internal Player:  Processor pegged regardless of whether or not 
deint is enabled
    MPlayer:                     80% Idle

These are the same results as my "fool Myth into thinking the VOB is a 
recording"
method.  Clearly there must be some major difference between how Myth's 
internal player is
playing back video and how MPlayer is playing back the same video.  It 
could be
configuration and/or other factors.  A while back a message was posted 
by someone who
claimed that they had enabled some optimizer options when they compiled 
one of the addon
modules and cpu idle time (for that module) went from %30 to %10.  Could 
this apply here also.

Clearly, with my internal player as it is (misconfigured or whatever), I 
will not be able to "watch
live tv" using a PVR250 and will have to opt for a PVR350.  But....from 
what appears to be objective
testing, I /should/ be able to use a PVR250 if I can get the internal 
player to perform at least close to
the level of performance of MPlayer.  So...does anyone have any ideas on 
whaat playback configuration
items I could play around with to see if I can get some processor back?  
I've don't use any filters and
I have already tried disabling deint.  Suprisingly though, disabling 
deint had almost zero effect on
processor idle time.  That is very curious to me.

Just out of curiosity, is there a way to make the frontend use MPlayer 
instead of it's internal player when
playing back recordings or watching live TV?  A performance comparison 
there might reveal some
interesting information also.  Just to be clear, I'm not intending to 
complain about this, I just wanted to
present my observations for comments etc..  Once again, thanks for any 
advice, comments, etc.


>>    
>>
>>>I've searched the archives and asked the question several times and
>>>this is the first
>>>response from any of my posts that tells me how to do this.  Thank
>>>you.
>>>
>>>      
>>>
>>Note that (last time I checked) the internal player still needs a little
>>work.  It still has some issues with seeking in certain types of files,
>>notably AVI containers, and I've noticed that I get bad interlacing
>>artifacts when playing back my Xvid .avi movies.  Of course, I'm about
>>a month behind CVS right now, but I don't recall seeing anything on the
>>-commits list that addressed this.  (JDS, if you're reading this, are
>>there any updates in this area?)  Also, you'll want to build a
>>seektable for your mythvideo files.  You can do this by running
>>"mythcommflag --video <filename>".
>>    
>>
>
>I've not done anything with the internal player since .16 was
>released.  I do plan on finishing up the outstanding issues, I just
>haven't had time.  Adding a seek table *should* make seeking in avi's
>bearable though.
>  
>
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-- 
Michael J. Lynch

What if the hokey pokey IS what it's all about -- author unknown




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