[FFmpeg-devel] SWSCALE: Colorspace conversion for images

[Michael Niedermayer]

On Tue, Mar 29, 2011 at 11:56:17PM -0700, Frank Barchard wrote:
> On Tue, Mar 29, 2011 at 2:40 PM, Michael Niedermayer <michaelni at gmx.at>wrote:
> 
> > On Tue, Mar 29, 2011 at 01:58:57PM -0700, Frank Barchard wrote:
> > > Bump swscaler width limitation from 5120 to 16384.
> > >
> > > Advantage: images (ie jpeg) are often larger than 5120 these days.
> > >  5120x2880 is about 15 megapixels
> > >
> > > Disadvantage: slightly slower
> > >
> > > no scaling
> > > timex ffmpeg -y -i tulip2.mp4 tulip2.yuv
> > > timex 8866.21ms
> > >
> > > scaling
> > > C:\ffwork>timex ffmpeg -y -i tulip2.mp4 -s 1272x724 tulip2.yuv
> > > timex 23633.13ms with VOFW 5120
> > > timex 26246.90ms with VOFW 16384
> >
> > uhm
> > could you try 21504 instead of 16384 ?
> >
> 
> 21504 works better.  Heres a benchmark
> 
> VOFW 5120  VOFW 21504    Note10438.8    10344.2       timex ffmpeg -y
> -i tulip2.mp4 tulip2.yuv25611.9    24256.9       timex ffmpeg -y -i
> tulip2.mp4 -s 1272x724 tulip2.yuv24485.7    26006.6       "28573.1
> 24291.3       "24069.1    26995.9       "25684.95   25387.675
> average

something is wrong with your mail client, this table is really messed
up badly whitespace wise,maybe you used html mail and mailman removes
html, but maybe it was something else i didnt really try to investigate

heres it reformated back to readable:
VOFW 5120  VOFW 21504    Note
10438.8    10344.2       timex ffmpeg -y -i tulip2.mp4 tulip2.yuv
25611.9    24256.9       timex ffmpeg -y -i tulip2.mp4 -s 1272x724 tulip2.yuv
24485.7    26006.6
"28573.1   24291.3
"24069.1    26995.9
"25684.95   25387.675    average


> 
> This is on a Nehalem i7.  Despite being a 500 frame, 720p video, the numbers
> fluctuate, so I took an average of 4 runs.
> 
> Another reason I'd like this change is youtube accepts videos with higher
> resolutions than 5120.
> 16384 is vp8's maximum resolution, so that should keep us amused for a
> little longer.
> I thought 16k would fix into L1 better, but I guess it had collisions.
> 
> diff --git a/libswscale/swscale_internal.h b/libswscale/swscale_internal.h
> index daa6731..fc684f1 100644

will apply the patch in a moment locally and push later


[...]
--
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Everything should be made as simple as possible, but not simpler.
-- Albert Einstein
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