Extracting coordinates (x y z) from a BVH file I want to extract coordinates in x y z format from a BVH file.

I read about the rotational and transational matrices used in a BVH file but cannot make any sense out of it.

At last i want to make python script to extract these coordinates and them feed them to another python script which uses BPY for animation of a character in Blender.

Any kind of references in this context would help too.
You can find a lot of helpful information by taking a look at Blender's import and export scripts for BVH located in /your/install/dir/2.80/scripts/addons/io_anim_bvh or if you have cloned the repository /your/git/repo/blender-git/blender/release/scripts/addons/io_anim_bvh or online in diffusion.

As you can see in the importer (line 173), the file contains so called channels which contain the x,y,z-coordinates. Since I'm not familiar with the format I can't tell you exactly how the matrix transformations work, but given that the importer script is rather short you may be able to figure this out on your own.