Talk:SOFA specifications - Revision history

Petibub at 08:25, 15 October 2014

2014-10-15T08:25:12Z

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	SimpleFreeFieldSOS : Simple Free Field Second Order Sections		SimpleFreeFieldSOS : Simple Free Field Second Order Sections
			== Data types ==

	==Description==		==Description==

Tcarpent at 19:45, 13 October 2014

2014-10-13T19:45:15Z

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	We encourage to use the 'History' attribute to store informations relative to the modelization (algorithm(s) used to derive the IIR model, method used to estimate the monaural delays, etc.)		We encourage to use the 'History' attribute to store informations relative to the modelization process (algorithm(s) used to derive the IIR model, method used to estimate the monaural delays, etc.)

Tcarpent at 14:47, 13 October 2014

2014-10-13T14:47:11Z

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	Bi(z) = bi0 + bi1 z^(-1) + bi2 z^(-2)		Bi(z) = bi0 + bi1 z^(-1) + bi2 z^(-2)

	Ai(z) = ai0 + ai1 z^(-1) + ai2 z^(-2)		Ai(z) = ai0 + ai1 z^(-1) + ai2 z^(-2)

Tcarpent at 14:46, 13 October 2014

2014-10-13T14:46:14Z

← Older revision		Revision as of 16:46, 13 October 2014
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	[ B1(z) A1(z) B2(z) A2(z) .... Bp(z) Ap(z) ] == [ b10 b11 b12 a10 a11 a12 b20 b21 b22 a20 a21 a22 .... bp0 bp1 bp2 ap0 ap1 ap2 ]		[ B1(z) A1(z) B2(z) A2(z) .... Bp(z) Ap(z) ] == [ b10 b11 b12 a10 a11 a12 b20 b21 b22 a20 a21 a22 .... bp0 bp1 bp2 ap0 ap1 ap2 ]


	SimpleFreeFieldSOS convention : everything similar to SimpleFreeFieldHRIR except the following:		SimpleFreeFieldSOS convention : everything similar to SimpleFreeFieldHRIR except the following:
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	Data.SOS of size [ M R N ] contains the filter coefficients. N being the total number of coefficients, it is always a multiple of 6.		Data.SOS of size [ M R N ] contains the filter coefficients. N being the total number of coefficients, it is always a multiple of 6.
	(N = 6 * p)		(N = 6 * p).

			The SimpleFreeFieldSOS does not impose any restriction on the filter coefficients contained in Data.SOS. Especially it is the user responsibility to check whether the filters are stable or not.

	Data.Delay is [M R] and contains the monaural delay (expressed in samples).		Data.Delay is [M R] and contains the monaural delay (expressed in samples).

Tcarpent at 14:42, 13 October 2014

2014-10-13T14:42:09Z

← Older revision		Revision as of 16:42, 13 October 2014
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	This convention is essentially the same as SimpleFreeFieldHRIR except that it is adapted to a parametric model of HRIR.		This convention is essentially the same as SimpleFreeFieldHRIR except that it is adapted to a parametric model of HRIR.

	This parametric model consists of replacing HRIR (as FIR) with a monaural delay and second order sections filters.		This parametric model consists of replacing HRIR (as FIR) with a monaural delay and second order sections filters.

Tcarpent at 14:41, 13 October 2014

2014-10-13T14:41:49Z

← Older revision		Revision as of 16:41, 13 October 2014
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	==Proposal for SimpleFreeFieldSOS ==		==Proposal for SimpleFreeFieldSOS ==
	For the sake of simplicity, we consider that all the filters ~~is the cascade~~ are second order filters (i.e. no first order filter). (anyway a first order filter can be represented with a second order filter).		For the sake of simplicity, we consider that all the cascaded filters are second order filters (i.e. no first order filter). (anyway a first order filter can be represented with a second order filter).

	The SOS is represented as follows:		The SOS is represented as follows:
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	(even though the denominator is usually normalized such that ai0 = 1).		(even though the denominator is usually normalized such that ai0 = 1).

			For each filter H(z), the filter taps are arranged as follows:

			[ B1(z) A1(z) B2(z) A2(z) .... Bp(z) Ap(z) ] == [ b10 b11 b12 a10 a11 a12 b20 b21 b22 a20 a21 a22 .... bp0 bp1 bp2 ap0 ap1 ap2 ]

	SimpleFreeFieldSOS convention : everything similar to SimpleFreeFieldHRIR except the following:		SimpleFreeFieldSOS convention : everything similar to SimpleFreeFieldHRIR except the following:
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	Data.SOS of size [ M R N ] contains the filter coefficients. N being the total number of coefficients, it is always a multiple of 6.		Data.SOS of size [ M R N ] contains the filter coefficients. N being the total number of coefficients, it is always a multiple of 6.
			(N = 6 * p)

	Data.Delay is [M R] and contains the monaural delay (expressed in samples).		Data.Delay is [M R] and contains the monaural delay (expressed in samples).

Tcarpent at 14:39, 13 October 2014

2014-10-13T14:39:12Z

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	where p is the number of second order sections.		where p is the number of second order sections.
			Each second order section is represented by 6 filter taps:

			Bi(z) = bi0 + bi1 z^(-1) + bi2 z^(-2)
			Ai(z) = ai0 + ai1 z^(-1) + ai2 z^(-2)

			(even though the denominator is usually normalized such that ai0 = 1).

Tcarpent at 14:37, 13 October 2014

2014-10-13T14:37:28Z

@@ Line 19: / Line 19: @@
 ==Proposal for SimpleFreeFieldSOS ==
 For the sake of simplicity, we consider that all the filters is the cascade are second order filters (i.e. no first order filter). (anyway a first order filter can be represented with a second order filter).
 SimpleFreeFieldSOS  convention : everything similar to SimpleFreeFieldHRIR except the following:
@@ Line 27: / Line 34: @@
 Data.Delay is [M R] and contains the monaural delay (expressed in samples).

Tcarpent at 14:34, 13 October 2014

2014-10-13T14:34:16Z

← Older revision		Revision as of 16:34, 13 October 2014
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	==Proposal for SimpleFreeFieldSOS ==		==Proposal for SimpleFreeFieldSOS ==
⚫	~~Everything~~ similar to SimpleFreeFieldHRIR except the following:

	For the sake of simplicity, we consider that all the filters is the cascade are second order filters (i.e. no first order filter). (anyway a first order filter can be represented with a second order filter).		For the sake of simplicity, we consider that all the filters is the cascade are second order filters (i.e. no first order filter). (anyway a first order filter can be represented with a second order filter).

		⚫	SimpleFreeFieldSOS convention : everything similar to SimpleFreeFieldHRIR except the following:

			DataType is 'SOS' (standing for 'second order sections').

	DataType is 'SOS'

	Data.SOS of size [ M R N ] contains the filter coefficients. N being the total number of coefficients, it is always a multiple of 6.		Data.SOS of size [ M R N ] contains the filter coefficients. N being the total number of coefficients, it is always a multiple of 6.

	Data.Delay is [M R] and contains the monaural delay (~~in the units of N i.e.~~ in samples).		Data.Delay is [M R] and contains the monaural delay (expressed in samples).

Tcarpent at 14:33, 13 October 2014

2014-10-13T14:33:13Z

← Older revision		Revision as of 16:33, 13 October 2014
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	DataType is 'SOS'		DataType is 'SOS'

	Data.SOS of size [ M R N ] contains the filter coefficients. N being the total number of coefficients, it is always a multiple of 6.		Data.SOS of size [ M R N ] contains the filter coefficients. N being the total number of coefficients, it is always a multiple of 6.

	Data.Delay is [M R] and contains the monaural delay (in the units of N i.e. in samples).		Data.Delay is [M R] and contains the monaural delay (in the units of N i.e. in samples).