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Topic: Pqf Specs (Read 1983 times) previous topic - next topic

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  • wkw
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Pqf Specs
Hi,

I am wondering if someone could verify for me if I got the right info for the AAC pqf filterbank. I only have the MPEG4 Final Committee Draft copy and I am not sure if there are any mistakes in the Final specs.

The 48 Q coefficients:

9.7655291007575512e-05, 
-2.2656858741499447E-02,
1.3809589379038567E-04,
-6.8031113858963354E-03,
9.8400749256623534E-05, 
1.5085400948280744E-02,
-8.6671544782335723E-05, 
3.9750993388272739E-02,
-4.6217998911921346E-04, 
6.2445363629436743E-02,
-1.0211814095158174E-03, 
7.7622327748721326E-02,
-1.6772149340010668E-03,
7.9968338496132926E-02,
-2.2533338951411081E-03, 
6.5615493068475583E-02,
-2.4987888343213967E-03, 
3.3313658300882690E-02,
-2.1390815966761882E-03, 
-1.4691563058190206E-02,
-9.5595397454597772E-04,
-7.2307890475334147E-02,
1.1172111530118943E-03, 
-1.2993222541703875E-01,
3.9091309127348584E-03, 
-1.7551641029040532E-01,
6.9635703420118673E-03,
-1.9626543957670528E-01,
9.5595442159478339E-03, 
-1.8073330670215029E-01,
1.0815766540021360E-02, 
-1.2097653136035738E-01,
9.8770514991715300E-03, 
-1.4377370758549035E-02,
6.1562567291327357E-03, 
1.3522730742860303E-01,
-4.1793946063629710E-04,
3.1737852699301633E-01,
-9.2128743097707640E-03, 
5.1590021798482233E-01,
-1.8830775873369020E-02, 
7.1080020379761377E-01,
-2.7226498457701823E-02, 
8.8090632488444798E-01,
-3.2022840857588906E-02, 
1.0068321641150089E+00,
-3.0996332527754609E-02, 
1.0737914947736096E+00

The Analysis filter's cosine modulator :

h[n] = 0.25cos((2i + 1)(2n + 5)PI/16)
n = 0,1...96
i=0,1,2,3

The Syntesis filter's cosine modulator :

h[n] = cos((2i + 1)(2n - 3)PI/16)
n = 0,1...96
i=0,1,2,3


Thanks

wkw

  • menno
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  • Developer (Donating)
Pqf Specs
Reply #1
Ok, didn't feel like comparing, so I copied it from the official spec:

0 9.7655291007575512E-05 24 -2.2656858741499447E-02
1 1.3809589379038567E-04 25 -6.8031113858963354E-03
2 9.8400749256623534E-05 26 1.5085400948280744E-02
3 -8.6671544782335723E-05 27 3.9750993388272739E-02
4 -4.6217998911921346E-04 28 6.2445363629436743E-02
5 -1.0211814095158174E-03 29 7.7622327748721326E-02
6 -1.6772149340010668E-03 30 7.9968338496132926E-02
7 -2.2533338951411081E-03 31 6.5615493068475583E-02
8 -2.4987888343213967E-03 32 3.3313658300882690E-02
9 -2.1390815966761882E-03 33 -1.4691563058190206E-02
10 -9.5595397454597772E-04 34 -7.2307890475334147E-02
11 1.1172111530118943E-03 35 -1.2993222541703875E-01
12 3.9091309127348584E-03 36 -1.7551641029040532E-01
13 6.9635703420118673E-03 37 -1.9626543957670528E-01
14 9.5595442159478339E-03 38 -1.8073330670215029E-01
15 1.0815766540021360E-02 39 -1.2097653136035738E-01
16 9.8770514991715300E-03 40 -1.4377370758549035E-02
17 6.1562567291327357E-03 41 1.3522730742860303E-01
18 -4.1793946063629710E-04 42 3.1737852699301633E-01
19 -9.2128743097707640E-03 43 5.1590021798482233E-01
20 -1.8830775873369020E-02 44 7.1080020379761377E-01
21 -2.7226498457701823E-02 45 8.8090632488444798E-01
22 -3.2022840857588906E-02 46 1.0068321641150089E+00
23 -3.0996332527754609E-02 47 1.0737914947736096E+00

Didn't check if the corrigenda contain corrections to this, but they are available for free.

Synthesis modulator is correct, couldn't find the analisys modulator that fast.

Menno

  • wkw
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Pqf Specs
Reply #2
thanks

wkw

  • wkw
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Pqf Specs
Reply #3
MPEG4 AAC -SSR Profile PQF - IPQF coeficients are LOUSY!!!
Could anyone verify my conclusions?


wkw

  • menno
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  • Developer (Donating)
Pqf Specs
Reply #4
The order you have them in, in your first post, is wrong.
In my posting the index is in front of the coefficients, just compare (hint: there are 2 columns).

Menno