Anamorphic H.264 MP4 (and likely all other video without a 1:1 SAR) does not display at the correct aspect ratio. I believe this is the same problem as reported in Issue #62, however that says it's a feature request for more display size options, when in reality this is a flat out bug and separate. The fullscreen size does NOT work as it should when playing such videos. (I'm not sure if the original size option works as it should either.)

The GoogleTV device I'm using is an LG 47GA6400 running the most recently available Google TV software. Based on Issue #62, I'm going to say it's present in the core Google TV software, however. To reproduce the problem use the built-in video player and attempt to play any anamorphic H.264 MP4 video file (or likely any other anamorphic video file).