As with the DAT and pss movies i wrote an almost working tool for these some time ago, which can be found at:
http://space.chimerica.de/code/tex-to_png.c and http://space.chimerica.de/code/tex-to_raw_rgba.c
Note that the to_png version requires lodepng which can be found at http://lodev.org/lodepng/
This will convert most textures, however, i found that some frames will come out as garbage. If someone can provide some info on this, ill gladly update the code.