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Lossy Audio Compression => AAC => AAC - Tech => Topic started by: pratheekp on 2011-01-27 06:59:48

Title: Princen Bradley condition
Post by: pratheekp on 2011-01-27 06:59:48
Can any1 explain me the Princen Bradley condition required for windows in MDCT
1.  h(k)^2 + h(k+N)^2 = 1

2. h(k) = h(2N-1-k)
Title: Princen Bradley condition
Post by: SebastianG on 2011-01-27 11:54:17
Can any1 explain me the Princen Bradley condition required for windows in MDCT
1.  h(k)^2 + h(k+N)^2 = 1
2.  h(k) = h(2N-1-k)

Try implementing the MDCT in terms of the Type-IV DCT (http://www.hydrogenaudio.org/forums/index.php?showtopic=20449&pid=200459&st=0&). This may help you understand the necessary window conditions to make the "whole" transform (many blocks) reversible and optionally orthogonal.
Title: Princen Bradley condition
Post by: .alexander. on 2011-01-27 13:50:12
One more MDCT related question. MDCT is a lapped transform and psychoacoustic models rather use FFT (both 'even' and 'odd' components included). Wouldn't it be right to adjust masking thresholds using prior knowledge of quantization errors in previous frame?
Title: Princen Bradley condition
Post by: .alexander. on 2011-01-28 19:41:29
Any ideas? I believe either Sebastian or Chris Helmrich should have thought about it..
Title: Princen Bradley condition
Post by: saratoga on 2011-01-28 20:14:10
Can any1 explain me the Princen Bradley condition required for windows in MDCT
1.  h(k)^2 + h(k+N)^2 = 1

2. h(k) = h(2N-1-k)


http://guru.multimedia.cx/mdct/ (http://guru.multimedia.cx/mdct/)

Title: Princen Bradley condition
Post by: Borneq on 2015-01-04 14:05:36
Can any1 explain me the Princen Bradley condition required for windows in MDCT
1.  h(k)^2 + h(k+N)^2 = 1

2. h(k) = h(2N-1-k)


and not
h(k) = h(2N-k) instead of h(2N-1-k) ?
Title: Princen Bradley condition
Post by: xnor on 2015-01-04 14:54:12
No, this just ensures symmetry and k starts with 0. (see n in my post here (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=107937&view=findpost&p=885859))
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