By Andy Covell Encoding Media is prepared for network delivery by another piece of software, called an encoder. In a live Webcast scenario, the encoder sends the stream directly to a media server, where it is rebroadcast in multicast or unicast streams. For on-demand streaming, the encoder creates a compressed file, which is then copied to a content directory on the server.
Compression is fundamental to what an encoder does.
Compression formats typically used for video or audio delivery via local storage are entirely inadequate for streaming, given bandwidth constraints. Now, ITU H.263 and MPEG-4 compression are among the options available in streaming products, but vendors still offer proprietary technologies that they say provide superior quality and performance. To deliver a quality experience, streaming transmissions must encounter minimal disruption. In fact, having a continuous, uninterrupted flow of data is more important than having complete data. Unfortunately, firewalls often disable UDP traffic, so streaming-media players can switch to TCP or HTTP streaming if UDP traffic is blocked.