The simple answer is yes, they contain calories. But even if you took 25g during or around your cardio that would only be about 100 calories. I actually favor amino acids over whole protein in that sort of situation since amino acids stimulate a greater release of insulin which is anti-catabolic.
Sorry to break it to you, but that isn't a BCAA supplement. BCAA's are the amino acids with aliphatic side chains (leucine, isoleucine, and valine)and are known for their effect on retaining muscle tissue. If you look at the ingredients, your "BCAA" pills really look like whey protein in pill form that contain all 8 essential amino acids. I guess you can take them before exercise, but I don't know if the lysine, leucine, and valine present is a high enough dosage to have much of an effect. If you really want to know the calories, add up all the milligrams of amino acids in one pill, divide by a thousand to get it to grams, and multiply by 4 (4 calories / gram of protein). I wouldn't worry about the calories though as it should be minimal and also, it's protein.
I wouldn't waste money buying these pills again. Don't try to cut corners to save money. Get an actual BCAA supplement because what you bought here is basically extremely expensive protein powder in pill form. Look at Biotest's real BCAA supplement. It should give you an idea of what you want to look for in terms of the amino acid breakdown and dosage. http://www.T-Nation.com/readArticle.do?id=1123403
So basically, if I took 5g around about 30 mins light cardio (on an empty stomach) that would maybe be enough to prevent muscle breakdown?? I'm not looking to lose bodyfat, but I'm looking to prevent gains in fat, hence limiting my calories
But its probably just like an "Amino 1000" pill I have had. Basically just all the amino acids (everything in small amounts of course) including the ones that are just metabolised in the liver for energy.
The only time I ever take normal amino acids like that would be in addition to BCAA before fasted cardio.