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Re: [Public WebGL] Video capture




Have you seen the Screen Capture API work too? http://w3c.github.io/mediacapture-screen-share/

Lots of privacy/security discussion already gone into that too.

roBman


On 27/01/15 8:04 PM, Ben Adams wrote:
Hi Florian

Thank you for starting this thread. The usecase I'm coming from would be Youtube/Twitch/Hangout/Custom Let's Play type videos or remote support.

To a degree whether it can capture only canvas or the entire window (internal) would alter whether the UI is html based or WebGL based.

For support we could suck the pages' html down in a datastream a to a degree reconstruct but that's not very efficient or faithful to what the end user would see; which may be the issue that is trying to be diagnosed.

On 27 January 2015 at 08:27, Florian Bösch <pyalot@gmail.com <mailto:pyalot@gmail.com>> wrote:

    A requirement that I have encountered a few times now is the need
    to produce a video from the canvas content. In my case, it usually
    was in order to save this video to disk. Another usecase mentioned
    by Ben Adams is a bit more generic (not just a canvas) and more
    aimed at being able to stream the video via WebRTC and the like.

    There are some libraries perform this task for canvas, such as:

    * https://github.com/spite/ccapture.js
    * https://github.com/antimatter15/whammy

    However they usually suffer from low speed (JS only encoding),
    incompleteness (no interframe compression and only basic
    intraframe compression) and so are not suitable for substantial
    video lengths and produce bulky files.

    A desirable solution would provide the following characteristics:

    * Fast to encode (preferrably realtime, i.e. < 8ms/frame)
    * Achieves good compression
    * If possible makes use of hardware supported video encoding found
    in some GPUs
    * Should at a minimum be able to capture canvas (but if possible a
    broader range of elements)
    * Should be amenable to progressive encoding (i.e. not block
    during an encoding task so that an application can be
    interactively used and simultaneously video encoding is operated)

    Usecases for this functionality can include:

    * Web based 3D editors and rendering movies
    * Web based video compositors
    * Collaboration tools (presentation, authoring, etc.)
    * Generally productivity tools of any kind whose output may
    contain video




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