[gentoo-user] Re: mplayer(2) ???

[Nikos Chantziaras]

On 09/23/2011 12:54 AM, Mick wrote:
> On Thursday 22 Sep 2011 09:15:42 Nikos Chantziaras wrote:
>> On 09/22/2011 12:58 AM, Mick wrote:
>>> On Wednesday 21 Sep 2011 09:19:39 Sebastian Beßler wrote:
>>>>> Does mplayer2 work with smplayer or kmplayer?
>>>>
>>>> I use mplayer2 with smplayer for a few month now and everything works
>>>> just fine for me.
>>>
>>> Any idea when ffmpeg-mt might make it to the main portage tree?
>>
>> It's already in the tree.  Both ffmpeg as well as libav now have it.
>
> Sorry I can't see a USE flag or ffmpeg-mt package in portage:
>
> $ eix -l ffmpeg | grep mt
> $
>
> or are you saying that the code has been merged in the vanilla ffmpeg and
> libav without the need for a USE flag?

ffmpeg-mt is not a "package".  It's the name of the git branch the code 
was in.  That code was merged into the fmmpeg and libav projects.  That 
means that ffmpeg and libav now do multi-threading.

Furthermore, the "threads" USE flag does *not* control this.  You get 
multi-threading regardless of that flag.  "threads" only controls 
another type of multi-threading that was there since a long time now, 
but doesn't perform well.  It would split decoding of each frame into 
multiple threads, and the CPU cores would not start decoding again until 
the whole frame was finished.  The speed-up you get by this is minimal. 
  "Real" multithreading, meaning the code from the ffmpeg-mt branch 
which allows every CPU core to fully decode its own video frame, cannot 
be controlled by a USE flag.

To verify if multi-threading works for you, simply play an h264 video 
file in mplayer2 (using "-lavdopts threads=N", where N is the number of 
CPU cores in your system) and use something like "top" or "htop" to 
check CPU load of each core.