6.4.1 CroppingTwo counters are used to identify the pixel in each line and the line in each field:• The pixel counter PXCNT counts the pixels of each scanline. Thecounter is reset to 0 at the beginning of each new scanline, i.e. witheach HSYNC.• The line counter LNCNT counts the lines of each field. LNCNT is resetto 0 at the beginning of each new field, i.e. with each VSYNC.The size of the area to capture is defined by two registers:• VInSTARTX.STARTX[9:0] defines the first pixel of each line tocapture. Thus if the pixel counter equals the VInSTARTX value, allfollowing pixels of the scanline are captured and passed on forfurther processing.Note that in case of YUV(4:2:2) data capturingVInSTARTX.STARTX[9:0] must be even, i.e.VInSTARTX.STARTX0 = 0.• In case of interlaced capturing VInSTARTY.STARTY1[9:0] defines thefirst line of the first field and VInSTARTY.STARTY2[9:0] the first lineof the second field to capture. Thus if the line counter equals theVInSTARTY1 or VInSTARTY2 value, all following lines of therespective field are captured and passed on for further processing.In case of progressive capturing VInSTARTY.STARTY2[9:0] definesthe first line to capture, while VInSTARTY.STARTY1[9:0] is not ofconcern.Cropping of the image at the right and lower edge is done by the definition of thescaled width and height (VInSCALEDWIDTH and VInSCALEDHEIGHT) in thescaler unit.Interlaced mode In interlaced mode the first scanline to capture can be set independently for thefirst and second field, whereas VInSTARTY.STARTY1[9:0] defines the firstscanline of the first field and VInSTARTY.STARTY2[9:0] the first scanline of thesecond field.Example In the above example the incoming video data has the format (600 x 480) pixels.The first pixel to capture in each scanline shall be pixel 90, thusVInSTARTX = 0000 005AH.The first line to capture in each field shall be line 40, thusVInSTARTY = 0028 0000H. As progressive scan is assumed, theVInSTARTY.STARTY1[9:0] value doesn't matter.This setting enables to capture a maximum of (550 x 440) pixels. Cropping at theright and lower edge is performed in the scaler unit.Video Input (Ravin-M only) Chapter 6Preliminary User's Manual S19203EE1V3UM00 159
