[Mp4-tech] SPIHT after DCT

[Rosiles Gerardo-ra9355]

There have been at least a couple of publications (one by Klausutis and Madisetti I believe), where first all the 8x8 DCTs of an image are computed. Then the coefficients are reorganized as subbands. For instance, to form the LL subband all the DC coefficients are grouped on a 2-D array that mantains the spatial relationships. Same can be done for all other coefficients. For a wavelet-like configuration you do the following partition on each block:
  a b c c d d d d
  b b c c d d d d
  e e f  f  d d d d
  e e f  f  d d d d
  g g g g h h h h
  g g g g h h h h
  g g g g h h h h
  g g g g h h h h
Needless to say the performance is poor w.r.t. the DWT.
Anyways, this topic could be out of the scope for this list. Check the compression newsgroups, where you can get better information.
Cheers,
Gerardo
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-----Original Message-----
From: mp4-tech-bounces lists.mpegif.org [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Boris Felts
Sent: Thursday, April 08, 2024 11:38 AM
To: 'karunakar A.K.'; Mp4-tech lists.mpegif.org
Subject: RE: [Mp4-tech] SPIHT after DCT
SPIHT was designed for wavelet compression. It uses the redundancies between subbands of low and high orders to achieve the compression. It is particularly suited for the three structure of the wavelet coefficients.
I am not sure this could be applied to DCT, since the transform coefficient don't have the same characteristics.
Boris 
-----Original Message-----
From: mp4-tech-bounces lists.mpegif.org [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of karunakar A.K.
Sent: Wednesday, April 07, 2024 11:11 PM
To: Mp4-tech lists.mpegif.org
Subject: [Mp4-tech] SPIHT after DCT
Hi Everbody
  I am thinking of applying SPIHT after DCT. Is it possible? If not possible please tell me the reason. 
with regards
kk
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