Image Processing Reference
In-Depth Information
Live Encoding
Living on the Bleeding Edge
Streaming video efficiently is one of the biggest challenges involved in providing media
services to the public. Video compression is an important part of the technology toolkit,
but it is not the only thing that you need to consider. The challenges are extreme, especially
when you are providing premium content to a large audience. Traffic levels can rapidly
exceed any available bandwidth you can deploy from a single server, and so more inno-
vative solutions are required. This is truly leading-edge stuff. This advanced technology is
often called 'Bleeding Edge'—a play on words used because of the potential for failure and
the somewhat large expenditure involved.
Whether you are encoding video for delivery via the web or for broadcast TV appli-
cations, the concepts are essentially the same. However, although the coding of the video
is similar, the delivery format is different. Multiplexing is used for TV services in order to
make maximum use of the transport stream by delivering several channels within the
same stream.
Streaming content on a network is often used for delivery of live, encoded on-the-fly
content. The issues involved with making content available to sufficient people are dealt
with in Chapter 20, which discusses streaming. This chapter concentrates on issues to do
with live encoding the master stream.
You have a large number of companies to choose from for your encoding hardware
and software. As a general rule, encoding for the Internet is done with software running
on a desktop PC and encoding for broadcast delivery is done with hardware. This differ-
ence is becoming blurred as some Internet and broadband service providers use hard-
ware-assisted software encoders.
Streaming Basics
Let's briefly review the packetizing and serving mechanisms required to deliver a stream of
digitally coded video.
Your video and audio are encoded separately and the audio is then merged with the
video. This is sometimes called embedding or multiplexing. Multiplexing is a process that
Search WWH ::

Custom Search