A contribution encoder receives media from a source, encodes the media, and transmits the encoded media to a network-adaptive encoding system for eventual distribution to end users. The network-adaptive encoding system tests a network connection between the contribution encoder and the network-adaptive encoding system before transmission of the encoded media begins. The network-adaptive encoding system uses the results of the test to select appropriate values for parameters that define the encoding and transmission of the media. The selected parameter values are transmitted by the network-adaptive encoding system to the contribution encoder for use in encoding and transmitting the media.