Video on-demand has to do with the delivery what they call content, while the video phone is the deliver of person-to-person communication. These are not nearly the same, but they both involve video.

随需视频必须与传送他们所称的“内容“相关,而视频电话是一种,个人对个人的传送，那不是,大致相同的，但它们都包含视频。

麻省理工公开课 - 媒体、教育、市场课程节选

And your friend does not answer, and you're asking to speak with that person.

当接电话的人并不是你的朋友时，你希望可以与你的朋友通话。

Can 课堂 - SpeakingMax英语口语达人

I think so. But video phone has been very hard to achieve. It's either been to be expensive, or too crowded, or can we use the internet to finally introduce video phone and this is different from video on-demand.

我也这么认为，但视频电话要成功很困难,它要么很贵，要么很拥堵，或者我们是否可以使用互联网引入视频电话,这与随需视频是不同的。

麻省理工公开课 - 媒体、教育、市场课程节选