Request for finer control of resize function

[BMart1]

Hi,

When updating ipp I was happy to find ResizeSuperShiftInit. Please add shifting to ResizeAntialiasingLinearInit and the rest.

Second, while srcSize.width/dstSize.width works most of the time, sometimes you need control of the factor used to map between src and dst pixels. I believe older versions of ipp allowed this, but that's before I started using the library.

Third, when reducing the resolution with ResizeAntialiasing each dst pixel depends on 2*factor src pixels. I need to tweak this when converting from 1080p60 to 480i30. I want each frame to become a field. Now I convert each frame to 480p and discard half the lines. With shifting support I can only compute the needed pixels with correct pixel centers, but they are too blurred because it reads twice too many src pixels.

From https://www.intel.com/content/www/us/en/developer/articles/technical/the-intel-avx-realization-of-lanczos-interpolation-in-intel-ipp-2d-resize-transform.html I believe you can fullfill the three requests by tweaking the Init funcitons only.

Regards,
Bruno

[ShanmukhS_Intel]

Hi,

Thank you for posting in Intel Communities. We are looking into the requests shared by you. We will get back to you soon.

Best Regards,

Shanmukh.SS

[ShanmukhS_Intel]

Hi,

Thank you for your feedback. We have provided your feedback to the relevant team. At this moment there is no visibility when it will be implemented and available for use. Could you please let me know if we can go ahead and close this case?

Best Regards,
Shanmukh.SS

[BMart1]

Hi,

Yes, you can close the case. Thank you.

I also tried to contact Svetlana and Valentin directly to make my case but got no reply

Regards,
Bruno

[Ruqiu_C_Intel]

Hello Bruno,

I know the case has been close, but it's good if the comments below can help you.

> When updating ipp I was happy to find ResizeSuperShiftInit. Please add shifting to ResizeAntialiasingLinearInit and the rest.

At the moment we have no plans to add a shift to ResizeAntialiasingLinearInit. You can use WarpAffine with an offset, the limitation is that warpaffine does not support anti-aliasing.

> Second, while srcSize.width/dstSize.width works most of the time, sometimes you need control of the factor used to map between src and dst pixels. I believe older versions of ipp allowed this, but that's before I started using the library.

There are only rare cases where the scale factor cannot be determined in terms of source size and destination size. In these cases, you can use a workaround with WarpAffine.

>Third, when reducing the resolution with ResizeAntialiasing each dst pixel depends on 2*factor src pixels. I need to tweak this when converting from 1080p60 to 480i30. I want each frame to become a field. Now I convert each frame to 480p and discard half the lines. With shifting support I can only compute the needed pixels with correct pixel centers, but they are too blurred because it reads twice too many src pixels.

You could try scaling the image to a height of 240 and not dropping half the lines if that's applicable to your case.

[BMart1]

> You could try scaling the image to a height of 240 and not dropping half the lines if that's applicable to your case.

It looks bad without proper shift and antialising, tweaking the factor so it's not too blurred.