The first tools from the team of Fallout 4 Script Extender (F4SE), which is already very well known in the modders community by previous releases - FOSE and NVSE.
Currently only one utility is included in Random Fallout 4 Tools - ba2extract. It is used to extract ba2 files. Repacking is not supported.
There are two types of ba2 archives: general, and texture. General archives can contain anything, while texture archives are optimized for storing textures. There is no significant size advantage when comparing the two, but texture archives store textures in a more intelligent way that is friendlier to the runtime texture streamer. When reading a DDS file, finding the lower resolution textures requires seeking to, and therefore decompressing most of the file. This is inefficient, because in most cases you will care about the lower resolution mips first, when the object is off in the distance. Texture archives store any mips higher than 256x256 in their own separate blocks, while the 256x256 and below are all in their own block.
Please note that the values in the DDS header are not present in the original texture archive, and were chosen for compatibility rather than accuracy. Color textures are accurate, but DXGI_FORMAT_BC5_UNORM (normal maps) and DXGI_FORMAT_BC7_UNORM are definitely wrong. Add the -atifourcc command line option to use the ATI2 format in the DDS header for normal maps, giving you a file that you can open in nvidia's photoshop dds plugin. I have not tested if these files will work in the game - the game expects a DX10-style header with DXGI_FORMAT_BC5_UNORM explicitly specified.
ba2extract.exe [src] [dst] (-atifourcc)
As always, you are getting source code with the utility.
To download Random Fallout 4 Tools to your computer, use one of the links below.