DCTFwd

[Deleted_U_Intel]

have someone real example how init context and call function DCTFwd, if i have RGB image , 200x200 pixel in input buffer? I understand where i must set up interlaced or normal image and another stuff for DCTFwd.

[Vladimir_Dudnik]

Hi,

We have several samples which demostartes how to use DCT8x8 functions. Is it suitable for your purposes?

Regarding DCT functions which process whole image, in general, you need to allocate and initialize DCT context before DCT call. There are several special functions for that. Some function can allocate and initialize context in one call, other can do it separately (first, you get required buffer size, allocate memory and call "init" function).

Regards,

Vladimir

[Vladimir_Dudnik]

Hi,

so you need to call ippiDCTFwdInitAlloc_32f function to create and initialize DCT context structure for given image size. Do not forget to free DCT context with call of ippiDCTFwdFree function. Note, DCT functions uses working buffer to do transform, so you need to allocate it before DCT function call. You can obtain required buffer size with ippiDCTFwdGetBufSize_32f function. After that you can call ippiDCTFwd_32f functions family.

So, speaking shortly you need:

1 - create and initialize context

2 - obtain size and allocate work buffer

3 - do transform

Regards,

Vladimir