Welcome Guest ( Log In | Register )

Reply to this topicStart new topic
Transform Coders and speech / vocal like signals
post Jul 4 2004, 15:09
Post #1

MPEG4 AAC developer

Group: Developer
Posts: 398
Joined: 1-June 03
Member No.: 6943

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..
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:


RSS Lo-Fi Version Time is now: 6th October 2015 - 05:22