[MEncoder-users] Fwd: Questions on Mencoder performace

[larrystotler at netscape.net]

-----Original Message-----
From: Corey Hickey <bugfood-ml at fatooh.org>

>This thread is a bit confusing because there are two somewhat-separate
>performance topics we're talking about: encoding and decoding.

Well, actually, I was looking for info on why a 2.4Ghz mobile 
Celeron(p4) w/ 256k L2 is only about 30-50% faster than a P3 Xeon 
500Mhz on pass + and why it was only about 200-250% faster on 
pass=2:bitrate=1536.  I was also trying to see if it had to do with the 
hardware like a memory bottleneck or too small L2 cache or the encoding 
settings.  I noticed no difference between 512k L2 Xeons and 2048k L2 
Xeons.  However, if smaller than 512 is a problem, then that may be a 
bottleneck.

>H.264 is indeed higher quality, but yes, for decoding, it's quite a bit
>slower than MPEG-4. If MPEG-4 is still too slow for you, then try 
MPEG-2
>or MPEG-1. Decoding is faster, but, of course, the encoding isn't as
>efficient and they won't look quite as good.

I notice very little difference if any between an MPEG2 source file and 
the XviD that takes about 1/8 of the space.  That why I do everything 
at 1536. Some things would probably look fine at 768 or 1024, but that 
would mean testing each file and checking the quality(like bubbles - 
they show good).  With slow systems, it takes too long to see if a 
lower bitrate with a smaller file size would give me the quality I am 
looking for.

>If you use MPEG-2 or MPEG-1, then the lavc vs. xvid choice is 
unnecessary since xvid is MPEG-4-only.

Not looking for MPEG2 - Looking to convert from it to MPEG4.
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