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Topic: Transform Coders and speech / vocal like signals (Read 1622 times) previous topic - next topic

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  • wkwai
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Transform Coders and speech / vocal like signals
I understand that most psychoacoustic based transform coders have difficulties in
coding signals like speech or music clips with strong vocals..  From my listening tests.. I find that these clips seemed to lose some of its "original" quality..

One possible explanation has something to do with the mis-match between the masking threshold calculated in long block for a signal that changes rapidly in time.. and switching to short blocks isn't a good solution as it involves too much block switching..  In AAC there is the TNS tool which flattens the temporal envelope and provides a better matching between the masking thresh and the quantization noise..

Still it is NOT good enough.. The vocals sounded a little flat.. sometimes like someone singing with a "nose block"!! Pitch related problem ??

I wondered if the LTP tools will provide an even better modelling of these kind of signals..