[x264-devel] Re: Speed Issue

[dmoz]

Hi all,

Just a reminder for considering speed.

There are many complex (and computation hungry)
part of H264 is not implemented in current x264
code trunk, e.g. B mode for sub macroblock partitions,
16x16 and 8x8 direct mode, etc.

IMHO, it's not the time discussing program coding
level optimization, it's better pay more attention
to features and algorithm level optimization.

BTW, I'm studing JM codes now, I found it had done
many optimizations, especially in hotspots.
So I don't expect other implementations has 10 or
more faster at the same stream qulity(in RD sense).

zhy


----- Original Message ----- 
From: "Xiaojie Huang" <hworldjj at yahoo.com>
To: <x264-devel at videolan.org>
Sent: Monday, October 18, 2004 1:09 PM
Subject: [x264-devel] Re: Speed Issue


> 
> --- Loren Merritt <lorenm at u.washington.edu> wrote:
> 
> > On Thu, 14 Oct 2004, Xiaojie Huang wrote:
> > My benchmark: 1.5% faster. ymmv.
> > 
> > $> time ./mencoder-r50 -ovc x264 -x264encopts
> > qp_constant=20:subq=1:frameref=1:cabac in.avi
> > x264 [info]: analyse=64(44362ms) encode=16(11600ms)
> > write=9(6812ms) filter=8(5900ms)
> > x264 [info]: slice I:25   Avg size:19203
> > x264 [info]: slice P:1405 Avg size:5874
> > x264 [info]: slice I      Avg I4x4:521   I16x16:444 
> > x264 [info]: slice P      Avg I4x4:72    I16x16:104 
> >  P:275   P8x8:31    PSKIP:481 
> > x264 [info]: kb/s:1171.5 fps:19.880
> > 86.770u 1.780s 1:29.84 98.5%    0+0k 0+0io 2669pf+0w
> > 
> > $> time ./mencoder-xia -ovc x264 -x264encopts
> > qp_constant=20:subq=1:frameref=1:cabac in.avi
> > x264 [info]: analyse=65(44144ms) encode=15(10708ms)
> > write=9(6711ms) filter=8(5878ms)
> > x264 [info]: slice I:25   Avg size:19203
> > x264 [info]: slice P:1405 Avg size:5874
> > x264 [info]: slice I      Avg I4x4:521   I16x16:444 
> > x264 [info]: slice P      Avg I4x4:72    I16x16:104 
> >  P:275   P8x8:31    PSKIP:481 
> > x264 [info]: kb/s:1171.5 fps:20.204
> > 85.670u 1.830s 1:28.19 99.2%    0+0k 0+0io 2662pf+0w
> Encoding speed denpends on many parameters including
> the test sequence, QP, GOP structure, etc.
> Just for Intra coding, the following is the test
> result.
> For example: on P4 2.3G CPU, 256M
> parameter: x264 -i 1 -o mobile-x264.264 mobile.cif
> 352x288
> The original: 26.33 fps
> The modification: 29.50 fps
> The gain is 12%
>  
> > I think a better / more general way would be to
> > combine the analyse and 
> > encode functions. This would also be required for a
> > rate/distortion MB 
> > type decision (which I am trying to implement).
> Yes, there are many operations which can be merged to
> avoid extra computations.
> 
> Xiaojie Huang
>  
> 
> 
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