Online video editor

1. A method performed by a remote service, comprising:

receiving a composition schema having multimedia layers, including a video layer, for playback, in which timing and duration for one or more of the multimedia layers vary from each other;

performing playback of the composition schema in a composition player operating in a regular or headless browser;

generating a video representation from the composition schema during playback, wherein the generation includes applying a master clock object to each multimedia layer during playback in the composition player to sync each multimedia layer's clock with a master clock, such that properties including position and visibility of respective multimedia layers during playback are constant with the master clock on a per-tick basis; and

transmitting a reference to the generated video representation.

2. The method of claim 1 , in which the composition schema is in JSON (JavaScript Object Notation) format.

3. The method of claim 1 , in which the application of the master clock object includes executing a tick function at a constant rate during playback.

4. The method of claim 3 , in which the application of the master clock object includes checking time in and time out values of each multimedia layer to determine whether to expose or suppress a respective multimedia layer at a given time within the composition player.

5. The method of claim 4 , in which exposure includes showing, playing, or animating a multimedia layer, and suppression includes hiding or muting a multimedia layer.

6. The method of claim 3 , in which the multimedia layers include graphical and text layers, and the application of the master clock object includes checking a size, rotation, and opacity for graphical and text layers, and colors and fonts for the text layer.

7. The method of claim 3 , in which the multimedia layers further include an audio layer, and the application of the master clock object includes checking video and audio trim in and trim out values.

8. The method of claim 1 , in which the reference of the video representation is transmitted to a remote browser operating on a user's computing device.

9. The method of claim 1 , in which the browser is a headless browser running JavaScript that controls playback of the composition schema within a Document Object Model (DOM).

10. The method of claim 1 , in which the video representation is in MPEG4 (Moving Pictures Experts Group 4) format.

11. One or more hardware-based non-transitory computer-readable memory devices storing instructions which, when executed by one or more processors disposed in a computing device, cause the computing device to:

create a composition schema using a video editor inside a browser, the composition schema having multimedia layers including a video layer;

transmit the composition schema to a rendering engine operated by a remote service,

wherein the rendering engine generates a video representation from the composition schema using instantiated JavaScript objects inside a headless browser, in which, during playback of the composition schema, the rendering engine applies an interval-based master clock to each multimedia layer in the composition schema to align asynchronous clocks for each multimedia clock with the interval-based master clock such that properties including position and visibility of respective multimedia layers are constant with the interval-based master clock, in which the interval-based master clock is applied on a per-tick basis to each multimedia layer; and

play a stream of the generated video representation inside the browser.

12. The one or more hardware-based non-transitory computer-readable memory devices of claim 11 , in which the video representation is in (Moving Pictures Experts Group 4) format.

13. The one or more hardware-based non-transitory computer-readable memory devices of claim 11 , in which the multimedia layers further include an audio layer and graphical or text layer.