With EMS, the only limit to the number of HLS streams that can be created simultaneously is the performance of your machine, not the license type. However, the EMS can only output AAC audio. If you have existing MP3 streams, the EMS can transcode MP3 audio to AAC. You need to transcode different bitrates separately. This can be done simultaneously. There is no additional license required for the transcoder or for the number of streams transcoded.