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AMR-WB Encoder Decoder Basic Doubt, modes does not give correct bitrates...
audio_geek
post May 8 2008, 08:16
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Hi,
I downloaded AMR-NB/WB code from ITU-T website for development.
I compiled AMR-WB and tested with a 4 second speech stream @16KHz and 16bits/sample.
Using mode0 i.e. 6.6kbps mode it gives me encoded file as ~53KB size
BUT
I expect an encoded size of (6.6kbps*4*1000/8) bytes i.e. 3300 Bytes or ~3.2 KB

Again, input bitrate is 256kbps to the encoder and we are supposed to get 6.6kbps i.e. a compression gain ratio of ~38-39 but if we consider 53KB encoded stream as correct then the corresponding bitrate is ~108kbps which is a compression gain of 256/108 = 2.3 which seems to be very less for a speech encoder.

this is happening with all the mdoes...

I need to be clear on this to proceed further to development of the codecs.

AMR-NB also has same problem...

Please let me know the testing procedure and if I am missing out anything before I start.

Thank you.
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CPKTV
post Feb 1 2009, 19:56
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Posts: 99
Joined: 8-March 08
Member No.: 51874



QUOTE (audio_geek @ May 8 2008, 10:46) *
Hi,
I downloaded AMR-NB/WB code from ITU-T website for development.
I compiled AMR-WB and tested with a 4 second speech stream @16KHz and 16bits/sample.
Using mode0 i.e. 6.6kbps mode it gives me encoded file as ~53KB size
BUT
I expect an encoded size of (6.6kbps*4*1000/8) bytes i.e. 3300 Bytes or ~3.2 KB

Again, input bitrate is 256kbps to the encoder and we are supposed to get 6.6kbps i.e. a compression gain ratio of ~38-39 but if we consider 53KB encoded stream as correct then the corresponding bitrate is ~108kbps which is a compression gain of 256/108 = 2.3 which seems to be very less for a speech encoder.

this is happening with all the mdoes...

I need to be clear on this to proceed further to development of the codecs.

AMR-NB also has same problem...

Please let me know the testing procedure and if I am missing out anything before I start.

Thank you.


try Voice Age:
http://www.voiceage.com/freecodecs.php
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