Re: [Audacity-quality] Importing 16-bit AUP project into 3.0.0 set to 32-bit

[Bill W. <bi...@go...>]

> On 2021/04/01, at 5:41 AM, Peter Sampson <pet...@gm...> wrote:
> 
> 
> 
> On Wed, Mar 31, 2021 at 11:24 PM Bill Wharrie <bi...@go... <mailto:bi...@go...>> wrote:
> I tried this on Mac 10.15.7 and Audacity 3.0.0
> 
> Start 2.4.2
> Set Quality prefs to 16-bit
> Import some audio
> - note that the track is labeled as 16-bit
> Save the project
> Quit 2.4.2
> note the _data folder size
> 
> Start 3.0.0
> Set Quality prefs to 32-bit float
> Import the previously saved 2.4.2 project
> - note that the track is labeled as 32-bit
> Save the project
> - note the project size - same as the 2.4.2 project but shouldn't it be twice as big?
> Amplify the track by 20 dB
> - since the track is 32-bit float, this should be recoverable
> Amplify the track by -20 dB
> - note that the track is not recovered - it appears that it is 16-bit even though labeled as 32-bit
> 
> Testing on W10 with 2.4.2 and 3.0.1 I confirm Bill's findings.
> 
> a) with 2.4.2 the AUP project was 28.5MB
> b) with 3.0.1 the AUP3 is 28.9MB throughout with Bill's steps
> 
> If I than Exit Audacity and relaunch (keeping the 32-bit Quality setting and import the same 
> audio file then indeed the project is double the 16-bit size at 56.9MB

Yes you can import the audio file and the conversion to 32-bit happens properly.

When you import a version-2 AUP files the conversion to 32-bit is NOT done AND the track is labeled 32-bit when it is actually 16-bit.

> 
> But I'm struggling to get my head around what the actual bug is here - and in particular
> what we would actually log in Bugzilla.

Tracks in 16-bit AUP projects imported into version 3 are not converted to 32 bit when quality prefs set to 32-bit ?

— Bill

> 
> 
> This example does raise some interesting questions about bit-rate Quality settings though.
> 
> In Bill's example above 
> a) the user was working in 2.4.2 with a16-bit Quality setting
> b) they then upgrade to 3.x
> c) at this stage their Quality settings follow them in audacity.cfg and they remain at 16-bit
> d) they then take the conscious decision to upgrade their Quality to 32-bit ...
> Of course it could be an unconscious change by using Reset Configuration - or on Windows
> choosing the reset on install
> 
> 
> Now here's an interesting use-case
> 1) Set Quality to 16-bit
> 2) Record a short bit of audio
> 3) Observe it is 16-bit in the TCP
> 4) change Quality to 32-bit
> 5) Press Record
> 6) Observe recording continues in the 16-bit track (so is this new part 16-bit or 32-bit?)
> 7) Press Shift+Record
> 8) Observe: new tracks is created with 32-bit in the TCP
> 
> I'm thinking that mixed bit rates call well be another of our cans o' worms ...
> 
> 
> Peter.
> 
> 
> 
> 
> Importing 16-bit audio files into a 3.0.0 project with Quality prefs set to 32-bit properly converts the audio to 32-bit (I tried MP3 and AIF). So this appears to be an issue only when importing AUP projects.
> 
> — Bill
> 
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