# 2011-04-09 11:04:45     Is there a quick method to convert a half d1 image to cif ?

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2011-04-09 11:04:45     Is there a quick method to convert a half d1 image to cif ?

david wang (CHINA)

Message: 99713

HI, all

As we all know, when we capturing video image by an video decoder like tvp5150, we can get the yuv file format is D1 or half d1 uyvy422 directly. But ,if we need to encoder a cif size video, we 've to do a down scale from half d1 to cif. My question is , how to do that? The uyvy422 format is  U0 Y0 V0 Y1 U1 Y2 V1 Y3 .... ,we can't get the cif size by simply doing DMA. My way is, copy the V1 to  U1, and then do a step = 2 dma. The problem is the first step is very time cost, is there better way or simply way to do such a scale? Thanks !

2011-04-09 12:58:01     Re: Is there a quick method to convert a half d1 image to cif ?

Mike Frysinger (UNITED STATES)

Message: 99715

D1 is 720 x 486 which means half D1 is 360 x 243.  CIF is 352 x 288.  seems like the easiest thing would be to truncate the first and last 4 horizontal lines, and then do a black border of ~22 vertical lines on each side.

2011-04-09 23:15:02     Re: Is there a quick method to convert a half d1 image to cif ?

david wang (CHINA)

Message: 99722

Sorry, there're some confuse here, but I mean half d1 720x288, for PAL . So it's hard to crup it to 352X288.

2011-04-09 23:23:24     Re: Is there a quick method to convert a half d1 image to cif ?

Mike Frysinger (UNITED STATES)

Message: 99723

it isnt hard to crop 720x288 to 352x288.  throw away every other line, and put 7 blank lines before/after the image.  that's the only real way to do it "fast".  otherwise you'll need to add software scaling.

2011-04-19 04:00:37     Re: Is there a quick method to convert a half d1 image to cif ?

david wang (CHINA)

Message: 99997

I'm sorry, but I can't understand how to throw away every other line to crop 720x288 to 352x288. 720 is the row size, you can only get a 720x144. If you mean throw every other pixel in every line, you'll lost all the V pixels just like I metioned at the begin thread.

2011-04-22 03:39:58     Re: Is there a quick method to convert a half d1 image to cif ?

Scott Jiang (CHINA)

Message: 100122

use dma, xcount =4, U0Y0V0Y1 U2Y4V2Y5