On Fri, 2 Oct 2009, Christian Ebert wrote:
> Hi,
>
> [ sorry for half-hijacking the thread ]
>
> > If you only have one CPU/Core you don't even need mpeg2enc's -M 2
> > option. The only thing that might help you than is the buffer program
> > for buffering the I/O. The mjpegtools with the piping can only be mad
> > faster with more cores.
>
> Has bumping up the -M option a negative effect on quality?
No. But it also doesn't improve the encoding speed as much as
people would prefer. There are enough serialisation points in
the encoder that prevent effective parallel processing.
In the case of the original poster's thread - look at the size of the
frames being encoded? They are huge - 1024x768! A standard DVD
frame is 720x480 or perhaps 720x576 so it's not surprising to me
that a single cpu system takes 4x realtime to do 1024x768 frames!
One way to speed things up would be to scale the frames down to
1/2 the size before encoding.
The other way to speed things up would be a dual core cpu so that
other programs in the pipeline can run in parallel. The encoder
will realize some benefit from more cpus but the primary benefit
is that multiple stages in the pipeline can run in parallel without
taking cpu time away from the encoder.
Cheers,
Steven Schultz
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