Retrieving video and audio streams

For a project, I have to stream video and audio from some server to my computer. Any language can be used, so I choose Flash because it would be easy to make the player look cool. I’m wondering if these are possible:

[] Is it possible to retrieve only a portion of audio rather than the whole file at once? I want to be able to grab say the portion between 00:05 sec and 00:06 sec and play it.
] Similarly, can I retrieve any arbitrary frame from a motion jpeg video file?

A link to an article about this would be very much appreciated.