v4l2 loopback working fine with openCV but weird output on OBS

I'm as CS student and i'm trying to make a project where I output my webcam video flow but as an ascii art. In order to do so, I get the image from v4l2. then i use OpenCV to decode the image (i wasn't able to find an easier way to do so) Then i get the data from my openCV mat and, in a new buffer, create an ascii art from my image. after that i send data from my buffer in v4l2 but when i use the v4l2 loopback input on obs the output is realy weird (see image) I've tried to output the image in a new mat using opencv and the image output correctly. i really don't understand what happen neither why. Also i've tried to use discord instead of OBS the output is completely black ... Any help would be appreciate. Thanks by advance. (all my code is available through github, i'm not sure if i should post it since this is not stack overflow. if ever you need it just let me know i'll add a link) Expected Output (got from OpenCV): OBS Output :