Dear aspirant

Mechanical engineering is a division of Engineering that deals with the mechanics of physics and science to analyze, manufacture and design mechanical system

Automobile engineering focuses on the cars. It specifically deals with the designing of cars, operations in production of cars, designing of engines and fuel management. Thus, automobile engineering can be considered as a sub branch of automotive engineering. However, generally both the branches are used interchangeably to denote a branch dealing with motor vehicles. It is actually a branch for mechanical engineering

In terms of placement you may easily gey placed in mechanical than that of automobile as every firm needs mechanical engineer.

So now it's all your subject of interest whicb stream you prefer.