Image Processing Reference
In-Depth Information
Table 26-1 Media Delivery Protocols
Method
Description
File on locally attached file system.
file://
HyperText Transfer Protocol.
http://
HyperText Transfer Protocol—Secure.
https://
Microsoft Media Streaming.
mms://
Progressive Networks Media.
pnm://
Real-Time Protocol.
rtp://
Real-Time Streaming Protocol.
rtsp://
standard set of controls that video and audio plug-ins were expected to use. This would
lead to more portable JavaScript code.
26.5
Protocols
The video content may be delivered in various ways. These are indicated by the protocol
method, which prefaces the colon in a URL. Table 26-1 summarizes some common proto-
col methods.
26.6
Metafiles
Most of the player implementations use a reference- or metafile, which is referred to in the
HTML of the web page. This file doesn't actually contain any media, but it points to a file
or stream that does. This allows the media to be served in a variety of alternative ways. By
using an intermediate file, it avoids the user's having to republish the web pages when an
alternative server is used.
Another benefit is that some of these metafiles allow the construction of playlists or
the attachment of header and trailer clips. You can also usually define the in and out points
so that one clip file can serve several uses.
As you would expect, the different platforms support mutually exclusive file name
extensions, and the syntax of the metafile content is also different for every player family.
26.7
File Extensions
Table 26-2 summarizes the file-type extensions for the different metafile file formats.
A more extensive listing of file types that are relevant to video-compression activities
appears in Appendix I.
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