When are splice points in the MPEG-2 Transport Stream created?

Splice points in the MPEG-2 Transport Stream are created during the encoding process by the content provider. This is crucial because splice points are designed to facilitate seamless transitions between segments of video and to allow for the insertion or removal of content without causing disruption to the viewer's experience.

When the content is being encoded, specific points are marked within the stream to indicate where these transitions can occur effectively. This is important for managing advertising insertion and ensuring that playback systems can handle the stream correctly without significant delays or buffering.

In this context, it's clear why the other choices do not apply. The creation of splice points is not related to the moment of transmission, distribution, or playback; instead, it is a foundational part of the encoding process that sets the framework for how the content is structured and presented.