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Audacity keeps converting my 24 bit samples to 32 bit float.

Posted: Wed Jul 08, 2015 9:27 pm
by Madalert
audacity bit conversion problem.PNG
audacity bit conversion problem.PNG (199.3 KiB) Viewed 524 times
When I drag and drop (import) a sound file of 24 bit into audacity, it converts it into 32 bit even though I have it preferred to be set as 24 bit. what is happening here and what can I do to fix this problem?

Re: Audacity keeps converting my 24 bit samples to 32 bit fl

Posted: Thu Jul 09, 2015 12:31 am
by DVDdoug
I'm not sure where those default settings apply and where they don't...

But, there are very good reasons why audio editors generally use floating-point for internal-temporary storage.

Conversion from 24-bit integer to 32-bit floating-point (and back) is a lossless process so there's really no downside other than larger temporary files.

Re: Audacity keeps converting my 24 bit samples to 32 bit fl

Posted: Thu Jul 09, 2015 10:46 am
by steve
I think it's a bug, though fortunately a harmless one.

Audacity works internally in 32-bit float format, so generally it is better to work in 32-bit float format so as to reduce the number of format conversions.

I have logged this on the bug tracking system, but I would recommend that you change the default sample format to 32-bit float.

Re: Audacity keeps converting my 24 bit samples to 32 bit fl

Posted: Thu Jul 09, 2015 2:25 pm
by Gale Andrews
DVDdoug wrote:I'm not sure where those default settings apply and where they don't...
Assuming we are talking about WAV files, this is what currently happens

Code: Select all

Quality setting    File Format       Imports as         

16                      16                   16
16                      24                   32 
16                      32                   32

24                      16                   24                   
24                      24                   32 
24                      32                   32

32                      16                   32
32                      24                   32
32                      32                   32
DVDdoug wrote:Conversion from 24-bit integer to 32-bit floating-point (and back) is a lossless process so there's really no downside other than larger temporary files.
I thought that there were some large 24-bit numbers that did not have exact 32-bit float equivalents: http://forum.audacityteam.org/viewtopic ... 47#p117447.


Gale

Re: Audacity keeps converting my 24 bit samples to 32 bit fl

Posted: Thu Jul 09, 2015 3:43 pm
by steve
Gale Andrews wrote:I thought that there were some large 24-bit numbers that did not have exact 32-bit float equivalents: http://forum.audacityteam.org/viewtopic ... 47#p117447.
Strictly speaking, that is correct, but for signals below 0 dB the error is insignificant (we're talking about precision that is hundreds of times better than "CD quality" even in the worst case).