topic Re: Problem about the image convertion between BGR24 and YCrCb4 in Intel® Integrated Performance Primitives

Problem about the image convertion between BGR24 and YCrCb411

walkdeath — Sat, 29 Apr 2006 19:51:31 GMT

Hi,
I'm working on PXA270 using ipp5.0 for PCA.
I want to change the BGR24 to YCrCb411 and then use sample mpeg4 encoder to encode the image.
I have only found "ippiBGRToYCbCr411LS_MCU_8u16s_C3P3R" this function in the manul, so I use it to change the color formate.
But after the encode, the YCrCb411 image file seems to be unable to display by the simple_player offered by the ipp5.0 media sample.The back ground of the image is green and only a very little part of the image is colorful on the top but I could not specify what it is.
I guess maybe there is something wrong with funcion "ippiBGRToYCbCr411LS_MCU_8u16s_C3P3R".
Why does this problem happen? Why this fuction turns '8u' to '16s'? Is there any function just like "ippiBGRToYCbCr411_8u_AC4P3R"?

Re: Problem about the image convertion between BGR24 and YCrCb4

Vladimir_Dudnik — Mon, 01 May 2006 06:24:02 GMT

Hello,

if you will look at IPP manual, you will see that this function is related to JPEG codec. In JPEG codec pipeline, level shift is needed before doing DCT operation. I recomend you to take a look at IPP for IXP, it contain more rich set of functions in color-convertion domain.

Regards,
Vladimir

Re: Problem about the image convertion between BGR24 and YCrCb4

walkdeath — Tue, 02 May 2006 12:07:17 GMT

Hi, Thanks for your reply. But I'm working on the PXA270 board that I could only use ipp 5.0 for PCA...... So, if want to covert a image(yuv420p format, 176x144) to BGR24, what function could I use and how to set the parameters? I've tried a lot a function, but the converted image always wrong...

Re: Problem about the image convertion between BGR24 and YCrCb4

Vladimir_Dudnik — Tue, 02 May 2006 16:43:14 GMT

IPP for PCA contains less functionality, so if you feel some functionality is missed, please submit your request to Technical Support. You also can consider opportunity to move your code to IPP v5.1 for IXP, which also can run on PXA270 processors. The only limitation of IPP for IXP that it does not provide WMMX optimization.

Regards,
Vladimir

Re: Problem about the image convertion between BGR24 and YCrCb4

walkdeath — Tue, 02 May 2006 22:18:00 GMT

Thanks very much for your advise~~ Do you mean that ipp for IXP could work well on PXA270? So that I could use the UMC sample Code on PXA270 too?

Re: Problem about the image convertion between BGR24 and YCrCb4

Vladimir_Dudnik — Wed, 03 May 2006 03:56:32 GMT

Yes, exactly. Of course, it does not use WMMX optimization, but it will work.

Vladimir