RGBA to IYUV

ThexFrgba2iyuvfunction converts a 4-channel RGBA image to IYUV (4:2:0) format. The function outputs Y, U, and V planes separately. IYUV holds subsampled data, Y is sampled for every RGBA pixel and U,V are sampled once for 2row and 2column(2x2) pixels. U and V planes are of (rows/2)*(columns/2) size, by cascading the consecutive rows into a single row the planes size becomes (rows/4)*columns.

API Syntax

template  void xFrgba2iyuv(xF::Mat & _src, xF::Mat & _y_image, xF::Mat & _u_image, xF::Mat & _v_image)

Parameter Descriptions

The following table describes the template and the function parameters.

Table 1.xFrgba2iyuv Function Parameter Descriptions
Parameter Description
SRC_T Input pixel type. Only 8-bit,unsigned, 4-channel is supported (XF_8UC4).
DST_T Output pixel type. Only 8-bit,unsigned, 1-channel is supported (XF_8UC1).
ROWS Maximum height of input and output image (must be a multiple of 8).
COLS Maximum width of input and output image (must be a multiple of 8).
NPC Number of pixels to be processed per cycle; possible options are XF_NPPC1 and XF_NPPC8 for 1 pixel and 8 pixel operations respectively.
_src Input Y plane of size (ROWS, COLS).
_y_image Output Y image of size (ROWS, COLS).
_u_image Output U image of size (ROWS/4, COLS).
_v_image Output V image of size (ROWS/4, COLS).

Resource Utilization

The following table summarizes the resource utilization of RGBA to IYUV for different configurations, generated usingVivado HLS 2017.1tool for theXilinx Xczu9eg-ffvb1156-1-i-es1FPGA, to process a HD (1080x1920) image.

Table 2.xFrgba2iyuv Function Resource Utilization Summary
Operating Mode

Operating Frequency

(MHz)

 Utilization Estimate
BRAM_18K DSP_48Es FF LUT CLB
1pixel 300 0 9 816 472 149

Performance Estimate

The following table summarizes the performance of RGBA to IYUV for different configurations, as generated usingVivado HLS 2017.1tool for theXilinx Xczu9eg-ffvb1156-1-i-es1, to process a grayscale HD (1080x1920) image.

Table 3.xFrgba2iyuv Function Performance Estimate Summary
Operating Mode Latency Estimate
Max Latency (ms)
1 pixel operation(300Mhz) 1.8