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Topic: AMR WB codec quality? (Read 4887 times) previous topic - next topic
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AMR WB codec quality?

It is clear that mp3 and mp4 (aac) audio codecs very much depent on the quality of implementation (psychoacoustic model, which parts of signal should be more quantized than others, etc. etc...). Different implementations - different quality (lame, dolby, blade, quicktime...).

Does the same thing relate to speech codecs, for example AMR wideband? Since the implementation is very much standardized, can quality of the encoded speech be improved in some way? Or different implementations are meaningless or impossible?

I would appriciate very much if someone familiar with AMR could give me the answer.

AMR WB codec quality?

Reply #1 –
Quote
Does the same thing relate to speech codecs, for example AMR wideband? Since the implementation is very much standardized, can quality of the encoded speech be improved in some way? Or different implementations are meaningless or impossible?

I would appriciate very much if someone familiar with AMR could give me the answer.

I can't tell for sure about AMR WB, but most speech codec have a bit-exact standard, meaning that a particular encoder input needs to produce exactly the same bit-stream on any (standard compliant) encoder. Some implementations may be faster/slower or use more/less memory, but the quality will be the same.

Of course, it's always possible to create a compatible non-bit-exact implementation, but there's generally much less room for improvement in speech codecs than general audio codecs.

AMR WB codec quality?

Reply #2 –
The specification of AMR-WB states clearly that the codec should be exact. This means that any implmentation of the AMR-WB should produce exactly the same bit stream for a specific input.

The difference between implementions on the same hardware platforms would mainly be the complexity.