[mythtv-users] Way OT, but a quick question about mencoder

[Kichigai Mentat]

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On Mar 20, 2006, at 18.32, Brian Wood wrote:

>
>
> On Mar 20, 2006, at 5:05 PM, Nick Rout wrote:
>
>>
>> On Mon, 20 Mar 2006 16:36:01 -0700
>> Brian Wood wrote:
>>
>>>
>>>
>>> On Mar 20, 2006, at 2:48 PM, Robin Hill wrote:
>>>
>>>> On Mon Mar 20, 2006 at 02:26:21PM -0700, Brian Wood wrote:
>>>>
>>>>> Anyone know if mencoder is capable of multi-threading. The
>>>>> system is
>>>>> capable of it (SMP kernel, proper libs etc) ??
>>>>>
>>>> A quick search suggests that only encoding using libavcodec
>>>> (lavc) is
>>>> multi-threaded.  Neither ffmpeg or xvid are currently multi- 
>>>> threaded
>>>> (though there has been some work on modifying xvid to utilise
>>>> multiple
>>>> threads so this in on the way).

LAVC has multi-threaded support, but it's slightly less efficient, or  
something. I don't use SMP, so I have no experience.

>>>
>>> Well I selected "Divx 4/5 (lavc)" in Konverter. Plus, if I try and
>>> run two jobs at the same time they both seem to get assigned to the
>>> same CPU :-(

That's different from a multi-threaded LAVC operation. That's two  
SEPARATE sets of threads. You probably need to invoke some kind of  
command to assign specific tasks to individual CPUs.

As far as using LAVC for a multi-threaded operation, I KNOW you have  
to invoke a specific option that Konverter probably isn't invoking.  
 From the MPlayer MAN page:

	threads=<1-8>
		Maximum number of threads to use (default: 1).  May have  a   
slight  negative effect on motion 			estimation.

>>>
>>> I'm brand new to the SMP world so I guess I have some studying up to
>>> do. This being pretty OT I'll find a better forum for "studying" the
>>> matter.
>>>
>>> Thanks for the pointer.
>>
>> Don't get me wrong, i think this is an interesting topic and is in
>> fact
>> on topic. But you may get more traction on one of the mplayer  
>> lists. I
>> am subbed to mplayer-users and there is quite a lot of tech
>> knowledge of
>> the inner workings of mplayer/mencoder
>>
>>
>
> Transcoding probably is more or less topical here, but what I need at
> this point is more general info about SMP and multi-threading, which
> is OT on this list.
>
> I may lurk on mplayer-users though, thanks for the tip.

Yeah, I also subscribe to MPlayer-Users, and they'll be a much better  
help.
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