And, the ones used in open-sourced FAAC encoder...what are those algorithms?
Thx much.
Full Version: Mdct And Imdct Algorithms
What are the fastest algorithms being used in AAC encoders right now? Can anyone give me some information about that?
And, the ones used in open-sourced FAAC encoder...what are those algorithms?
Thx much.
And, the ones used in open-sourced FAAC encoder...what are those algorithms?
Thx much.
Hi,
Just some references you might want to investigate:
The last item is one of the latest algorithms. I did not include integerized algorithms here.
As for the best algorithm, that depends on your requirements. Typically, there is a trade-off between the number and type of computations and the required memory.
Good luck!
Just some references you might want to investigate:
- A fast algorithm for the implementation of filter banks based on TDAC, Duhamel et al, 1991.
- Fast algorithms for orthogonal and biorthogonal MLT, Malvar, 1998.
- A new fast algorithm for the unified forward and inverse MDCT/MDST computation, Britanak et al, 2002.
The last item is one of the latest algorithms. I did not include integerized algorithms here.
As for the best algorithm, that depends on your requirements. Typically, there is a trade-off between the number and type of computations and the required memory.
Good luck!
QUOTE
And, the ones used in open-sourced FAAC encoder...what are those algorithms?
FAAC and FAAD use (I)MDCT implementation with FFT kernel of 1/4 size of N. This is very efficient implementation of (I)MDCT.
You might also want to check U.S. patent application# 2002/0106020 A1 that deals with optimized MDCT for audio coding.
QUOTE(petracci @ Jul 4 2003, 12:15 AM)
Hi,
Just some references you might want to investigate:
The last item is one of the latest algorithms. I did not include integerized algorithms here.
As for the best algorithm, that depends on your requirements. Typically, there is a trade-off between the number and type of computations and the required memory.
Good luck!
Just some references you might want to investigate:
- A fast algorithm for the implementation of filter banks based on TDAC, Duhamel et al, 1991.
- Fast algorithms for orthogonal and biorthogonal MLT, Malvar, 1998.
- A new fast algorithm for the unified forward and inverse MDCT/MDST computation, Britanak et al, 2002.
The last item is one of the latest algorithms. I did not include integerized algorithms here.
As for the best algorithm, that depends on your requirements. Typically, there is a trade-off between the number and type of computations and the required memory.
Good luck!
thx...where can i find those documents?
Strange patent application. It seems to me to be a patent on a mathematical computation, and not really on a process.
I thought this was not allowed.
I thought this was not allowed.
QUOTE(Ivan Dimkovic @ Jul 4 2003, 12:40 AM)
FAAC and FAAD use (I)MDCT implementation with FFT kernel of 1/4 size of N. This is very efficient implementation of (I)MDCT.
You might also want to check U.S. patent application# 2002/0106020 A1 that deals with optimized MDCT for audio coding.
You might also want to check U.S. patent application# 2002/0106020 A1 that deals with optimized MDCT for audio coding.
thx, i read the homepage and find that very complicated
Hi, here goes...
Duhamel, P.; Mahieux, Y.; Petit, J.P.;
A fast algorithm for the implementation of filter banks based on TDAC.
Acoustics, Speech, and Signal Processing, 1991. ICASSP-91., 1991 International Conference on , 14-17 April 1991 Page(s): 2209 -2212 vol.3
Malvar, H.;
Fast algorithms for orthogonal and biorthogonal modulated lapped transforms
Advances in Digital Filtering and Signal Processing, 1998 IEEE Symposium on , 5-6 June 1998 Page(s): 159 -163
Vladimir Britanak and K. R. Rao
A new fast algorithm for the unified forward and inverse MDCT/MDST computation, Elsevier Signal Processing, Volume 82, Issue 3, March 2002, Pages 433-459
Duhamel, P.; Mahieux, Y.; Petit, J.P.;
A fast algorithm for the implementation of filter banks based on TDAC.
Acoustics, Speech, and Signal Processing, 1991. ICASSP-91., 1991 International Conference on , 14-17 April 1991 Page(s): 2209 -2212 vol.3
Malvar, H.;
Fast algorithms for orthogonal and biorthogonal modulated lapped transforms
Advances in Digital Filtering and Signal Processing, 1998 IEEE Symposium on , 5-6 June 1998 Page(s): 159 -163
Vladimir Britanak and K. R. Rao
A new fast algorithm for the unified forward and inverse MDCT/MDST computation, Elsevier Signal Processing, Volume 82, Issue 3, March 2002, Pages 433-459
QUOTE(Gabriel @ Jul 4 2003, 08:50 AM)
Strange patent application. It seems to me to be a patent on a mathematical computation, and not really on a process.
I thought this was not allowed.
I thought this was not allowed.
Well, it's just a patent application - nobody guarantees that it is going to be granted
QUOTE(Gabriel @ Jul 4 2003, 10:50 AM)
Strange patent application. It seems to me to be a patent on a mathematical computation, and not really on a process.
I thought this was not allowed.
I thought this was not allowed.
The application is on the efficient implementation of the mDCT, not on the mathematical computation. This is allowed. But there are already many applications/patents on various implementations, it is hard to see how this one differs from the rest.
QUOTE(petracci @ Jul 4 2003, 01:03 AM)
Hi, here goes...
Duhamel, P.; Mahieux, Y.; Petit, J.P.;
A fast algorithm for the implementation of filter banks based on TDAC.
Acoustics, Speech, and Signal Processing, 1991. ICASSP-91., 1991 International Conference on , 14-17 April 1991 Page(s): 2209 -2212 vol.3
Malvar, H.;
Fast algorithms for orthogonal and biorthogonal modulated lapped transforms
Advances in Digital Filtering and Signal Processing, 1998 IEEE Symposium on , 5-6 June 1998 Page(s): 159 -163
Vladimir Britanak and K. R. Rao
A new fast algorithm for the unified forward and inverse MDCT/MDST computation, Elsevier Signal Processing, Volume 82, Issue 3, March 2002, Pages 433-459
Duhamel, P.; Mahieux, Y.; Petit, J.P.;
A fast algorithm for the implementation of filter banks based on TDAC.
Acoustics, Speech, and Signal Processing, 1991. ICASSP-91., 1991 International Conference on , 14-17 April 1991 Page(s): 2209 -2212 vol.3
Malvar, H.;
Fast algorithms for orthogonal and biorthogonal modulated lapped transforms
Advances in Digital Filtering and Signal Processing, 1998 IEEE Symposium on , 5-6 June 1998 Page(s): 159 -163
Vladimir Britanak and K. R. Rao
A new fast algorithm for the unified forward and inverse MDCT/MDST computation, Elsevier Signal Processing, Volume 82, Issue 3, March 2002, Pages 433-459
i cannot find those documents in google.
can anyone help? thx
[quote=kennyzero,Jul 4 2003, 12:58 AM] [QUOTE=Ivan Dimkovic,Jul 4 2003, 12:40 AM] FAAC and FAAD use (I)MDCT implementation with FFT kernel of 1/4 size of N. This is very efficient implementation of (I)MDCT.
[/quote]
I think the 8 FFT implementation of the 2048 MDCt/ IMDCT is more efficient than one that uses 4 FFT.
[/quote]
I think the 8 FFT implementation of the 2048 MDCt/ IMDCT is more efficient than one that uses 4 FFT.
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