ffmpeg -f flv -i rtmp://// -f flv -i rtmp://// \ 
                         -filter_complex "[1:v]scale=w=96:h=72[ckout];[0:v][ckout]overlay=x=W-w-10:y=H-h-10[out]" -map "[out]" \ 
                         -c:v libx264 -profile:v high -preset medium \ 
                         -filter_complex amix -c:a aac \ 
                         -f flv -y
                    
                        rtmp:////merge
                    
                    
                    && 
                    echo "ok"