NV21 to YUV4

ThexFnv212yuv4function converts an image in the NV21 format to a YUV444 format. The function outputs separate U and V planes. Y plane is same for both formats. The UV planes are duplicated 2x2 times to represent one U plane and V plane of YUV444 format.

API Syntax

template void xFnv212yuv4(xF::Mat & src_y, xF::Mat & src_uv, 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.xFnv212yuv4 Function Parameter Descriptions
Parameter Description
SRC_T Input pixel type. Only 8-bit, unsigned, 1-channel is supported (XF_8UC1).
UV_T Input pixel type. Only 8-bit, unsigned, 2-channel is supported (XF_8UC2).
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.
NPC_UV Number of UV image Pixels to be processed per cycle; possible options are XF_NPPC1 and XF_NPPC4 for 1 pixel and 4-pixel operations respectively.
src_y Input Y plane of size (ROWS, COLS).
src_uv Input UV plane of size (ROWS/2, COLS/2).
_y_image Output Y plane of size (ROWS, COLS).
_u_image Output U plane of size (ROWS, COLS).
_v_image Output V plane of size (ROWS, COLS).

Resource Utilization

The following table summarizes the resource utilization of NV21 to YUV4 for different configurations, as generated in theVivado HLS 2017.1version tool for theXilinx Xczu9eg-ffvb1156-1-i-es1FPGA, to process a HD (1080x1920) image.

Table 2.xFnv212yuv4 Function Resource Utilization Summary
Operating Mode

Operating Frequency

(MHz)

 Utilization Estimate
BRAM_18K DSP_48Es FF LUT CLB
1pixel 300 0 0 1383 817 233
8pixel 150 0 0 1887 1087 287

Performance Estimate

The following table summarizes the performance of NV21 to YUV4 for different configurations, as generated using theVivado HLS 2017.1version tool for theXilinx Xczu9eg-ffvb1156-1-i-es1, to process a grayscale HD (1080x1920) image.

Table 3.xFnv212yuv4 Function Performance Estimate Summary
Operating Mode Latency Estimate
Max Latency (ms)
1 pixel operation(300Mhz) 13.8
8 pixel operation(150Mhz) 3.5