track(" In a Smooth Streaming presentation, a contiguous set of chunks encoded at a specific bit rate and stored in a media container format (also called a "wire format"). For Smooth Streams encoded for Silverlight-based clients, the chunks are encoded as MPEG-4 (MP4) fragments and stored in either Smooth Streaming video (.ismv) or Smooth Streaming audio (.isma) containers. A Smooth Streaming presentation typically contains multiple tracks encoded at different bit rates.")
