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.
What is speex :Speex is a new audio codec introduced in flash player 10 and above. It overcomes many limitations of old Nellymoser codec. This new codec will provide better audio quality using less bandwidth. Speex can be used for both kind of communication , through Flash Media Server or P2P.Speex is opensource so it can be decoded or converted to any format unlike nellymoser .
Speex Description: Speex encoder and decoder are present in flash player 10 and above. Speex compression is controlled by setting encodeQuality. Encode quality can be set using 11 quality levels 0(Lowest) - 10(Highest).Default value is 6. Speex encoder for flash works in constant bit-rate (CBR) . Speex is designed for Voice over IP (VoIP) which means it provides high quality speech at low bit rate.
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.our tests 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 Speex uses 42.2 kbps thats half of the bandwidth being used by nellymoser which is 88.2
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.
Speex
Speex Quality , Bandwidth and filesize table | ||
| Quality (encodeQuality) | Required bandwidth in kbps | Per minute file size in KB |
| 0 | 3.95 | 28.9 |
| 1 | 5.75 | 42.1 |
| 2 | 7.75 | 56.7 |
| 3 | 9.80 | 71.7 |
| 4 | 12.8 | 93.7 |
| 5 | 16.8 | 123.0 |
| 6 | 20.6 | 150.8 |
| 7 | 23.8 | 174.3 |
| 8 | 27.8 | 203.6 |
| 9 | 34.2 | 250.4 |
| 10 | 42.2 | 309.0 |
Nellymoser
Quality(mic.rate) Required bandwidth in kbps
5 11.025
8 16
11 22.05
22 44.1
44 88.2
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