I'm a registered user of MX Player (MX Player Pro) and I miss this feature on my NVIDIA SHIELD TV. NVIDIA is not going to add automatic frame rate switching because they say this feature should be implemented in each video application, not in firmware. MX Player is the video player with the best picture quality I have ever seen, but this feature is necessary on NSTV because we have to set the frame rate manually in Settings for each video file.
Thank you. Best regards.