I am currently having a BSc degree in Computer Science. I want to get into AAA game industry. My focus is on the core stuffs like rendering, physics, graphics programming. I plan to get a master's degree for that. Now, should I choose a broader branch, Computer Graphics, or should I go for the specific Game Development for the degree? Note: It maybe easier for me to get the Computer Graphics degree. And I know that I have to show some complete projects, practical knowledge, passions to get the job in the industry.

Pick the course that most closely matches your interests and what you would like to do in an eventual job.

Entry level rendering roles are quite rare, but having those skills will make you an attractive candidate to employers.

Also be aware that some "game development" courses can be a bit fluffy and end up with you being a jack of all trades, master of none. Check the syllabus to work out if this applies in your case.

I believe that going to CG would allow you to have more choices/freedom once you finished your studies.

I mean, if in 5 or 10 years, you would prefer to move to something more general, more scientific or more technic, it might be more easy with a CG degree than with a GD one.

Computer science for both, an emphasis on computer graphics if you want.

Having worked through the program myself, and having watched others do it, I personally count a master's degree as roughly akin to six months of real job experience plus a slightly deeper exposure to some algorithms.  It helps the person advance their career faster, and only provides a tiny benefit to the job.  

A "game development" degree is not very useful generally, it cannot be used in fields other than games.  Often they are considered 'trade degrees' that don't meet the standards of a CS degree.  Over my decades I've seen more than one person who went to game schools and then were rejected from master's degree programs.

One in particular went to Full Sail, barely passed the GRE tests, and was still rejected because the grad school said his academic background probably wasn't up to the math rigor involved. I quizzed him myself on his math, and while he knew a of the game-related math of 3-d linear algebra and some statistics he was severely lacking in topics like calculus and anything not used in games. His former teachers at the school helped contact the school that rejected him and negotiated for the school to test him with their math qualifier given to their own undergraduate students When he was done he said he didn't understand most of the things on there, even though he was at the top of the class in Full Sail for his math components.

The point of that is that game degrees are usually shortcuts relative to the full computer science degree. Get that degree if you are in a country where educational background matters.

As Frob said, "Game Development" degrees do tend to be very light a lot of the time. I mean I did a Games Programming specific degree and it was actually really in depth, but a handful of my friends did "Games Development" at uni and their final year stuff was making like basic 3d games in Unity etc, but they hadnt really learnt any maths.. any real C++, had no idea how to work with HLSL or GLSL really.. which is all like stuff that my course covered in first year..

So while there are some good game focused courses out there... the majority of them are really just more of an "Intro to Unity" kind of course from what i've seen.

For a Masters level it may be more in depth, but its still one of those risks