The most direct way to include video in a browser, is to extend an existing browser by modifying it's source code. For this to be possible, the browser source code must be available, as is the case with for instance NCSA Mosaic, the first widely known browser.
[67] describes rewriting Mosaic to support real-time video and
audio, to a browser called
Vosaic.
Vosaic accepts URLs of the form
referencing an MBone connection at address 224.2.252.51 at port 4739,
having a Time To Live (TTL) of 127, and using the nv
transmission format.
Rewriting browser source code requires people to install the modified version of the browser, which is not necessarily the browser of choice. In addition, when programmers around the world create their own versions of browsers, each extended to do various useful things, it will be difficult to incorporate all wanted behavior into a single browser. This leads to a scenario in which people use different browsers for different tasks, breaking with one of the basic goals of the WWW philosophy; incorporating all information into a single client program. Later sections describe ways to extend browsers in somewhat standardized ways, making it possible to add independent extensions to the same browser program without recompilations.