VideoMatte240K consists of 484 high-resolution green screen videos and generate a total of 240,709 unique frames of alpha mattes and foregrounds with chroma-key software Adobe After Effects. The videos are purchased as stock footage or found as royalty-free materials online. 384 videos are at 4K resolution and 100 are in HD. The videos are split by 479 : 5 to form the train and validation sets. The dataset consists of a vast amount of human subjects, clothing, and poses that are helpful for training robust models.