24 bits avec CoolEdit2000

Le
siger
Bonjour,
avec CoolEdit2000, on peut avoir 8, 16 et 32 bits flottants. Comment
peut-on avoir 24 bits ?

L'aide indique ça, mais je n'y comprends rien :
(ces options ne sont pas au moment d'enregister à partir d'une source,
mais au moment d'enregistrer le fichier)

- 32-bit int (type 1 - 32-bit)
This format saves 32-bit audio as 32-bit integers.

- 32-bit 24.0 float (type 1 - 24-bit)
Full 32-bit floats are actually saved (and in the range of +/-8
million), but the .wav BitsPerSample field is set to 24 while
BlockAlign is still set to 4 bytes per channel.

- 32-bit 16.8 float (type 1 - 32-bit)
Cool Edit 2000’s internal format (floating point values in the range of
+/-32768.0 but larger and smaller values are valid and not clipped
since the floating point exponent is saved as well).  The .wav
BitsPerSample field is set to 32 and BlockAlign to 4 bytes per channel.

- 32-bit 0.24 normalized float (type 3 - 32-bit)
Standard floating point format for type 3 .wav files.  Values are
normalized to the range +/-1.0 and although values above and below this
range are saved, some programs may clip when reading them back in (Cool
Edit will not clip, but read the save value back if it is beyond this
range).

- 24-bit packed int (type 1 - 24-bit)
Straight 24-bit integers are saved (so any data beyond the bounds are
clipped).  The .wav BitsPerSample field is set to 24 and BlockAlign to
3 bytes per channel. 

- 24-bit packed int (type 1 - 20-bit)
Straight 24-bit integers are saved (so any data beyond the bounds are
clipped).  The .wav BitsPerSample field is set to 20 and BlockAlign to
3 bytes per channel.  The extra 4 bits that are saved are actually the
remaining valid bits when saving, and are used when reading (thus
giving 24-bit accuracy still if those bits were actually when writing).
Applications should either fill those last 4 bits with zeros, or with
actual data, but generally A/D converters that generate 20 bits of
valid data automatically set the remaining 4 bits to zero. Any type 1
format with BlockAlign set to 3 bytes per channel is assumed to be
packed integers, and a BitsPerSample field between 17 and 24
inclusively will read in all 24 bits fine and assume the remaining bits
are either accurate or set to zero.
=

Merci.

--
siger
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siger
Le #13733361
siger a écrit :

avec CoolEdit2000, on peut avoir 8, 16 et 32 bits flottants.
Comment peut-on avoir 24 bits ?



J'ai trouvé une réponse sur le forum de l'éditeur :

============================= Just record in 32-bit. This is actually stored as 24-bit + exponent and
sign values anyway, and during the initial recording, the exponent is
filled with zeros. The exponent comes into its own when processing,
allowing the output to be scaled to an enourmous degree (about 1500dB)
without losing any resolution whatsoever.

I agree, it's a bit misleading seeing only 16 and 32 bit options when
recording, but it's fine, honestly! It would perhaps make more sense to
many if it said 16-bit (integer) and 32-bit (24-bit+7+1 Floating
Point), which is what it actually is.
=============================
Je comprends ce qu'il faut faire, mais pas comment ça marche.

Vous avez une explication plus claire ?

Merci.

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