Screen share service #18

Isolate screen sharing management to allow usage on other projects (like Sputniq)

Use a canvas on the HTML to allow image prtions painting.

Control sended image, and use fast / complete comparations to avoid send yet sended data.

Check changes using a pixel comparator, but comparing only one of each 4 square pixels. This allow the screen changes to be compared more fast. Use a offset in comparation to maje a full pixel comparation each 4 checkings comparing in this way:

[#·]    [··]    [·#]    [··]
[··]    [·#]    [··]    [#·]

The # indicates the pixel to check on each moment.

The changes must be merged into big change tiles.

The tiles will be 48X48 pixels. Once a changed was detected the tile is marked as changed, and must be resended.

Each change tile will be sended in a low quality mode. while the tile remain unchnaged qualitiest versions will be sended.

4 Quality steps

• Send a 50% version of the tile at 30% quality JPEG
• Send a full resolution 30% quality JPEG
• Send a full resolution 70% quality JPEG
• Send a full resolution pixel-perferct 24bits BMP

Use an automatic presseting on tiles, better connections will make the JPEG quality % to be bigger on all presets.