Resized to smaller size images render faster

[Ugo Stray]

Is it possible to optimize webp code to make resized to smaller size
images render faster? Usually decoding/resizing image of size 1024x768
takes same time as rendering its shrinked version, because you have to
read the whole file to get all information about the image and then
use resize function to make it smaller. WebP tecnology is based on
block prediction: the less is size of image, the less blocks it has to
predict, the less time it takes to resize it. If it's possible maybe
it could be used to make texture resizing in 3D graphics faster to
create a more realistic games!

[Pascal Massimino]

Hi,

On Fri, Jul 8, 2011 at 10:28 PM, Ugo Stray <plav...@gmail.com> wrote:

Is it possible to optimize webp code to make resized to smaller size
images render faster? Usually decoding/resizing image of size 1024x768
takes same time as rendering its shrinked version, because you have to
read the whole file to get all information about the image and then
use resize function to make it smaller. WebP tecnology is based on
block prediction: the less is size of image, the less blocks it has to
predict, the less time it takes to resize it.

unfortunately, prediction assumes one decodes everything, since the spatial

predictors are located on the boundary of the 16x16 or 4x4 blocks. This is the

downside of using spatial prediction. 

Still, doing on-the-fly resize reduces the CPU usage because there's less

yuv->rgb conversion operations to perform. And you can bypass the in-loop

filtering process if the reduction factor is important (for instance when you're

only extracting a thumbnail out of a large picture).

But most of all, the reduction in memory usage if the interesting part of

on-the-fly macroblock transformation.

If it's possible maybe
it could be used to make texture resizing in 3D graphics faster to
create a more realistic games!

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