Methods and systems for remotely editing a video file involve: receiving, at a server, a video editing command from a remote client; modifying, at the server, a virtual representation of a media file in accordance with the received command, the virtual representation including a reference to a source media file stored on a storage device, the storage device being connected to the server over a high-speed link; and generating and transmitting, from the server to the remote client, a proxy representation of the source media file modified by the editing commands, wherein the various regions of the proxy representation are rendered either in the background or in real-time according to their complexity. Rendered frames, whether generated in the background or in real time, are stored for reuse. Individual frames of the edited video file may be transmitted upon request from a client. Simultaneous editing of independent projects by multiple users connected to the server via multiple thin clients is supported.