Float

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Float (or fully IEEE floating point with single precision) is one of the sample types of AviSynth's audio. For a converter see [http://www.h-schmidt.net/FloatConverter/IEEE754.html here].
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''This page is about the ''Float ''audio format''. ''For the variable type, see [[Script_variables]]''. ''For the'' <code>Float()</code> ''function, go to [[Internal_functions#Float]]''
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'''Float''' (or fully IEEE floating point with single precision) is one of the [[ConvertAudio|AviSynth audio sample formats]].  
  
 
The samples of this type have values between -1.00000 (= 0xBF800000) and 1.000000 (= 0x3F800000).
 
The samples of this type have values between -1.00000 (= 0xBF800000) and 1.000000 (= 0x3F800000).
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The value of such a IEEE-754 number is computed as: sign * 2^exponent * 1.mantissa, using the following scheme:
 
The value of such a IEEE-754 number is computed as: sign * 2^exponent * 1.mantissa, using the following scheme:
  
[ 1 Sign Bit | 8 Bit Exponent  | 23 Bit Mantissa ]
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<code>[ 1 Sign Bit | 8 Bit Exponent  | 23 Bit Mantissa ]</code>
  
 
* The sign bit is 1 (negative) or 0 (positive).
 
* The sign bit is 1 (negative) or 0 (positive).
 
* The exponent runs from -127 (00000000) to 0 (0111111) to 128 (11111111).  
 
* The exponent runs from -127 (00000000) to 0 (0111111) to 128 (11111111).  
 
* The mantissa m1m2m3 ... means m1/2 + m2/4 + m3/8 + ... in decimal. Sometimes people denote "1.m1m2m3..." as the mantissa (like is done in the converter above).
 
* The mantissa m1m2m3 ... means m1/2 + m2/4 + m3/8 + ... in decimal. Sometimes people denote "1.m1m2m3..." as the mantissa (like is done in the converter above).
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For an on-line converter between decimal numbers and IEEE 754 floating point, see [http://www.h-schmidt.net/FloatConverter/IEEE754.html here].
  
 
Examples:
 
Examples:
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  Sign bit is negative, exponent = 0, 1.mantissa = 1, so the number is -1.0
 
  Sign bit is negative, exponent = 0, 1.mantissa = 1, so the number is -1.0
  
source: [http://www.opferman.net/Text/ieee.txt]
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source: [http://www.opferman.net/Text/ieee.txt opferman.net]
  
 
[[Category:Glossary]]
 
[[Category:Glossary]]

Revision as of 17:29, 17 September 2014

This page is about the Float audio format. For the variable type, see Script_variables. For the Float() function, go to Internal_functions#Float


Float (or fully IEEE floating point with single precision) is one of the AviSynth audio sample formats.

The samples of this type have values between -1.00000 (= 0xBF800000) and 1.000000 (= 0x3F800000).

The value of such a IEEE-754 number is computed as: sign * 2^exponent * 1.mantissa, using the following scheme:

[ 1 Sign Bit | 8 Bit Exponent | 23 Bit Mantissa ]

  • The sign bit is 1 (negative) or 0 (positive).
  • The exponent runs from -127 (00000000) to 0 (0111111) to 128 (11111111).
  • The mantissa m1m2m3 ... means m1/2 + m2/4 + m3/8 + ... in decimal. Sometimes people denote "1.m1m2m3..." as the mantissa (like is done in the converter above).

For an on-line converter between decimal numbers and IEEE 754 floating point, see here.

Examples:

0x3F800000 = 00111111100000000000000000000000 (binary, see [1])

Sign Bit      Exp       1.Mantissa
0          01111111  00000000000000000000000

127 - 127 = 0     1.0 bitshift 0 places

Sign bit is positive, exponent = 0, 1.mantissa = 1, so the number is +1.0

and

0xBF800000 = 10111111100000000000000000000000

Sign Bit      Exp       1.Mantissa
1          01111111  00000000000000000000000

127 - 127 = 0     1.0 bitshift 0 places

Sign bit is negative, exponent = 0, 1.mantissa = 1, so the number is -1.0

source: opferman.net

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