A satellite broadcast system is used to transmit streams of variable bit-rate content using fixed bit-rate channels that correspond to respective satellite transponder carriers. High bandwidth content is transmitted over multiple transponder carriers in parallel with a combined bandwidth sufficient for the peak bit-rate of the high bandwidth content, whereas multiple streams of low bandwidth content can be transmitted over a single transponder carrier simultaneously by multiplexing the low bandwidth content. High bandwidth content may be multiplexed with low bandwidth content rather than assigning all high bandwidth content to be transmitted exclusively over dedicated high bandwidth transponders.