[FFmpeg-devel] [PATCH] up VOFW in swscale?

[Andreas Öman]

Michael Niedermayer wrote:
> On Wed, Apr 01, 2009 at 09:28:46PM +0200, Andreas ?man wrote:
>> Hi
>>
>> I use the scaler to rescale photos (>2048 pixels wide) in my
>> application.
>> With the old scaler this was not a problem but nowadays it
>> no longer works since the maximum width is limited to 2048 pix.
>>
>> Therefore I propose we up this to 4096.
> 
> can post some benchmarks with a CPU with small cache and a low resolution
> video?

Interesting exercise. Seems that increasing it to 4096 causes more
cache aliasing. However, increasing it to 5120 makes it faster than
the original code.

Tested on:

model name	: AMD Sempron(tm) Processor 2800+
cpu MHz		: 1600.074
cache size	: 256 KB

Input #0, avi, from 
'/storage/media/Video/TV-series/Greys.Anatomy/Greys.Anatomy.S05E06.HDTV.XviD-0TV.avi':
   Duration: 00:41:40.75, start: 0.000000, bitrate: 1176 kb/s
     Stream #0.0: Video: mpeg4, yuv420p, 624x352 [PAR 1:1 DAR 39:22], 
23.98 tbr, 23.98 tbn, 23.98 tbc
     Stream #0.1: Audio: mp3, 48000 Hz, stereo, s16, 128 kb/s
Output #0, null, to '/dev/null':
     Stream #0.0: Video: rawvideo, yuv420p, 256x128 [PAR 39:44 DAR 
39:22], q=2-31, 200 kb/s, 90k tbn, 23.98 tbc


VOFW = 2048

user    3m28.760s
user    3m28.920s
user    3m29.290s
user    3m29.440s

VOFW = 4096

user    3m30.820s
user    3m30.380s
user    3m30.590s
user    3m30.220s

VOFW = 5120

user    3m27.680s
user    3m27.650s
user    3m27.620s
user    3m27.900s