The live-action kept the main side characters like Tsubaki and Watari. The live action focused on Kousei and Kaori.
It was, after all, classified as a drama. In contrast, the live-action took on a more steady approach.
This makes the roller coaster of emotions quite extreme.
In contrast, the movie only showed him joining one solo competition. It also portrayed a part of his life that was not directly attached to Kaori. The anime shows viewers Kousei’s growth and perseverance through three solo competitions.
There are no differences to the main plot and no added scenes.