VFX pipeline software is the system inside a visual effects studio that passes each shot from artist to artist, keeps track of every version, and lets the directors review the work. A large film can have 2,000 effects shots and several hundred artists working on them at once. Without a pipeline, nobody would know which version of which shot is the latest, or who is waiting for whom. Most large VFX studios build their own pipeline software, because their way of working is their advantage over other studios.
A pipeline does four jobs. First, it keeps a database of every shot: its name, its frames, the departments it must pass through, the artist assigned in each department, and the deadline. Second, it stores the files. Each version of a shot is saved under a fixed name and folder, usually in object storage, so every program in the studio can find it. Very large files are tracked with version control for large files, which keeps every past version. Third, when an artist publishes a version, the pipeline tells the next department that new work is ready, and sends the rendering jobs to the studio's computers. Fourth, it collects the director's notes against each version.
Consider a stadium crowd shot, at a studio in Chennai. The film's cricket stadium was filmed nearly empty, and 40,000 computer-made fans must fill it. The shot is 6 seconds long, which is 144 frames at 24 frames per second. The crowd artist publishes version 3. The pipeline records it and starts the render. In a busy week, the studio's own computers are full. So the pipeline sends the render to servers rented from a GPU cloud, and the 144 frames come back in four hours. The compositor is told that the frames are ready. She combines the crowd with the filmed shot and publishes version 4 of the finished image.
The next morning, the director watches version 4 in a review session, and writes a note: "the fans in the top stand are too still". The pipeline attaches the note to version 4 and sends the shot back to the crowd artist. After three more rounds, version 7 is approved and marked final. If the director later asks which version was approved, the pipeline knows.
The pipeline also counts hours. Because the studio is paid a fixed price for the film, it needs to know how many artist hours each shot is taking. A shot that needs many more rounds than planned costs the studio money. The same tracking also lets FX simulation artists see which version of the animation they should simulate against.