License type: Nellymoser is closed format codec whereas Speex is opensource which means that files created using
speex can be decoded or encoded without any licence requirement.
Flash Player Requirement: Nellymoser works from Flash player 6 onwards whereas Speex requires atleast Flash Player 10. Although speex works with flash player 10 but there is a audio disturbance bug on listener end which was fixed in version 10,0,22,87.So player 10,0,22,87 and above is recommended.
Quality: Speex is optimised for speech so better quality is expected from speex as compared to our old Nellymoser codec.
Bandwidth Requirement: Speex delivers better quality than Nellymoser using less bandwidth as compared to Speex uses 42.2 kbps thats half of the bandwidth being used by nellymoser which is 88.2tests revealed that the quality with nellymoser becomes usable at 8(16kbps) where as in case of speex it is 3 (9.80 kbps).The highest quality in
Encode Quality: Speex provides more flexibilityby giving 11 levels of quality to choose from (0-10).0 is lowest and 10 is highest audio quality. Nellymoser gives 5 settings(5,8,11,22,44) ,5 is lowest and 44 is highest quality.Remember more is the quality higher is the bandwidth requirement which may lead to choppy sound when sufficient bandwidth is not available.
Playback: Speex files created by FMS, RED5 or WOWZA can be played very well in flash player but most of the offline players does not playback it due to lack of audio decoder for speex. Nellymoser can be played in most media players.