[1:v]split=4[a][b][c][d];
[a]crop=427:480:0:0,scale=352:288,drawtext=text=CAM1:fontcolor=yellow:fontsize=28:x=6:y=6:box=1,drawtext=text='%{pts\:hms}':fontcolor=white:fontsize=18:x=6:y=36:box=1[v1];
[b]crop=427:480:427:0,scale=352:288,drawtext=text=CAM2:fontcolor=yellow:fontsize=28:x=6:y=6:box=1,drawtext=text='%{pts\:hms}':fontcolor=white:fontsize=18:x=6:y=36:box=1[v2];
[c]crop=427:480:0:0,scale=352:288,drawtext=text=CAM3:fontcolor=yellow:fontsize=28:x=6:y=6:box=1,drawtext=text='%{pts\:hms}':fontcolor=white:fontsize=18:x=6:y=36:box=1[v3];
[d]crop=427:480:427:0,scale=352:288,drawtext=text=CAM4:fontcolor=yellow:fontsize=28:x=6:y=6:box=1,drawtext=text='%{pts\:hms}':fontcolor=white:fontsize=18:x=6:y=36:box=1[v4]