A test of a new intervention or treatment on people for. detecting. -Tolerability. -Safety. -Efficacy. A Clinical trial is defined as a prospective study. comparing the effect and value of intervention. (s) against a control in human beings.
In fact, whether the DVD players play AVI videos or not, it depends on the DVD player model, the AVI video codec or the AVI video resolution/size: 1  Most DVD players only accept MPEG-2 in standard VOBs. 2  Though some newer DVD players can play AVI files, it only plays AVI which is encoded with DivX. However, AVI is a container video format which may encoded with different video codecs like DivX, Xvid, MPEG-4, H.263, WMV, MPEG-1 and etc.
Don't know if it is the hardware problem or which dvd player software you are currently using, I'm also an Windows user and I just find that playing DVDs is just the basic function of 5KPlayer which, is a potential new media player that also works as a free dvd player software perfectly on my Windows 8.1 so far.