The best replacement for icecast is shoutcast.

The best alternatives to icecast are rated as following:
★★★★★  shoutcast
★  wowza

Your alternative for icecast is not listed? Suggest!
Speaking about icecast, one probably shouldn't forget about mpd.

Other search terms related to icecast and their ratings are:

★★★★★ mpd
★★★★★ icecast
★★★ ices
You have in mind a companion for icecast and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of icecast in all years. Click on graph for more.