Here are some useful snippets of code and/or shell commands.
How I dump stream from NASA TV (example):
mplayer -dumpstream -dumpfile sts123_`date +%Y%m%d%H%M%S`.ogg "mms://209.73.189.123/bcpenc252181?StreamID=59949564"
I've been converting MPEG files from my digital camera (HP Photosmart E327) into FLV (Flash Video), in order to embed some videoclips inside a web page.
I've found that this is the way to get the best audio/video quality:
ffmpeg -i sourcefile.mpg -sameq -acodec pcm_s16le -ar 44100 destfile.flv