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Tremor's mdct backward function
antrox87
post Jun 6 2009, 14:49
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Hi to all,
I'm trying to understand the Tremor's code that implements the iMDCT.
First of all.. Does it implement iMDCT throught a mechanism of rotation and FFT? I'm not sure of it..
If it's true.. where does implement the presorting?
Then.. the parameter "n" defines the dimension on witch the iMDCT is calculated (I know that the range on witch n is defined could be only between 64 and 8192 , multiples of 2). Is it the input's array dimension?

Thanks for answers

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ruchi sharma
post Oct 14 2009, 11:43
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QUOTE (antrox87 @ Jun 6 2009, 07:49) *
Hi to all,
I'm trying to understand the Tremor's code that implements the iMDCT.
First of all.. Does it implement iMDCT throught a mechanism of rotation and FFT? I'm not sure of it..
If it's true.. where does implement the presorting?
Then.. the parameter "n" defines the dimension on witch the iMDCT is calculated (I know that the range on witch n is defined could be only between 64 and 8192 , multiples of 2). Is it the input's array dimension?

Thanks for answers



Hi,
i am working on MDCT Backward of tremor's code.
i need to replace this to Duhamels algorithim.
can u plz help me out by any suggesstions or inputs??
i need to replace existing MDCT to duhamels FFT so as to increase the performance.
Thanks a lot.

Regards,
Ruchi
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saratoga
post Oct 14 2009, 14:26
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QUOTE (ruchi sharma @ Oct 14 2009, 06:43) *
Hi,
i am working on MDCT Backward of tremor's code.
i need to replace this to Duhamels algorithim.
can u plz help me out by any suggesstions or inputs??
i need to replace existing MDCT to duhamels FFT so as to increase the performance.
Thanks a lot.


I tried several FFT based IMDCTs in place of tremor's and all were slower. You will need a very fast FFT algorithm to beat Tremor. Lately I've been working on a slit radix version, but I have no idea if its going to be any faster smile.gif

If you want to try, take a look at one of the mdct.c files mentioned above and use your own FFT.

This post has been edited by Mike Giacomelli: Oct 14 2009, 14:26
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