DI is an acronym for Digital Intermediate or Data Intermediate by certain professionals, in the video editing process. It is the digital master from which a film intermediate is recorded.
It generally refers to the process of colour grading the final output. When you are looking to quality video output, you should know that you need to invest on additional budget and time.
Quality of your processed DI film is directly proportional to your budget and available time.
If you do not have the time or a budget, one may not get the movie like quality. For the common man, the grading difference is not noticeable though.
In this process of colour grading, there is an intermediate technician called the colorist, where the editor and the colorist work in tandem to improve the quality of the shots, focusing on individual frames, if required.
It is generally the high budget movies that go for this kind of colour grading because it offers great production value.