c++ - Combining two YV12 image buffers into a single side-by-side image -

i have 2 image buffers in yv12 format need combine single side-by-side image.

(1920x1080) + (1920x1080) = (3840*1080)

yv12 split 3 seperate planes.

yyyyyyyy vv uu 

the pixel format 12 bits-per-pixel.

i have created method memcpys 1 buffer (1920x1080) larger buffer (3840x1080), isn't working.

here c++.

byte* source = buffer; byte* destination = convertbuffer3d;  // copy on y (int x = 0; x < height; x++) {     memcpy(destination, source, width);     destination += width * 2;     source += width; }  // copy on v (int x = 0; x < (height / 2); x++) {     memcpy(destination, source, width / 2);     destination += width;     source += width / 2; }  // copy on u (int x = 0; x < (height / 2); x++) {     memcpy(destination, source, width / 2);     destination += width;     source += width / 2; } 

i expected this:

instead, result:

what missing?

what wanted this:

y1 y1 y1 y1 y2 y2 y2 y2 y1 y1 y1 y1 y2 y2 y2 y2 y1 y1 y1 y1 y2 y2 y2 y2 y1 y1 y1 y1 y2 y2 y2 y2 u1 u1 u2 u2 v1 v1 v2 v2 u1 u1 u2 u2 v1 v1 v2 v2 

but code doing this:

y1 y1 y1 y1 y2 y2 y2 y2 y1 y1 y1 y1 y2 y2 y2 y2 y1 y1 y1 y1 y2 y2 y2 y2 y1 y1 y1 y1 y2 y2 y2 y2 u1 u1 v1 v1 u2 u2 v2 v2 u1 u1 v1 v1 u2 u2 v2 v2 

here's corrected code (untested)

byte* source = buffer; byte* destination = convertbuffer3d;  // copy on y (int x = 0; x < height; x++) {     memcpy(destination, source, width);     destination += width * 2;     source += width; }  (int x = 0; x < (height / 2); x++) {     // copy on v     memcpy(destination, source, width / 2);     destination += width;     source += width / 2;      // copy on u     memcpy(destination, source, width / 2);     destination += width;     source += width / 2; }