Audacity 1.3.14 is around

[dlaloum]

Does V2.0 RC finally record at true 24bit?

[DaveinEL]

I've recorded what Audacity 2 RC2 has exported as a 24-bit 96 kHz wav file.
How do you recommend I confirm that it is 24-bit and not a padded 16-bit file?
I don't mean relying on my non-golden ears to distinguish the difference.

[jiiteepee]

I've recorded what Audacity 2 RC2 has exported as a 24-bit 96 kHz wav file.
How do you recommend I confirm that it is 24-bit and not a padded 16-bit file?
I don't mean relying on my non-golden ears to distinguish the difference.

Use a hex editor.

jiitee

[dlaloum]

In other words, look at the digital data directly - if all the bottom 8 bits have nothing but 0 in them....

it has been recorded in 16bit and then the bottom bits have been "packed" to fill it out to 24 bits - ie there is no additional data there.

[DaveinEL]

I looked at a 24-bit 96 kHz file I recorded with Audacity 2.0 RC2 with a hex editor.
I set up the view as binary and 3 columns so I got 3 columns of 8 digits ( 1 or 0 ).
When you look at the music part, there are only 0's in the last column, so the 3rd column is all 0's. Doesn't appear to have any data above 16-bits.
Out of curiosity I exported another recording as 32-bit float 96 kHz. I set the view as binary and 4 columns so I got 4 columns of 8 digits ( 1 or 0 ). When you look at the music part, there are only 0's in the first column. The other 3 columns have a mixture of 0's and 1's. Not sure what is going on here.
I did look at a 24-bit 96 kHz file I recorded with Audition and the 3 columns have a mixture of 0's and 1's which is what I expected.
If I can find another hard drive, I will load Mint Linux and record with Audacity at 24-bit 96 kHz to see if the Linux version can do better.

[LPfan]

How about asking the experts on the Audacity forum?

Regards,

LPfan

[davidsrsb]

I would expect the 17th + bits to be all over the place if the ADC is actually 24 bit, as noise floor is typically 18 to 20 bits. Recording a -90dB sine wave is probably the best way of finding true resolution. If Audacity capture is running in 16 bit it will have several percent distortion.

[Dimal]

In other words, look at the digital data directly - if all the bottom 8 bits have nothing but 0 in them....

it has been recorded in 16bit and then the bottom bits have been "packed" to fill it out to 24 bits - ie there is no additional data there.

G'day David...

I've opened a PCM file in one of the many free hex editors one can download, but I can't for the life of me translate your description above, into what I see in the editor. Any chance of showing some examples or a link to a site where this is explained to a layman such as myself....

Thanks,
Mal.

[dlaloum]

You need to be able to view the raw digital data, most commonly in Hex.
If the bottom 8bits are all 0, then all values will be above 100000000 (digital) or XXXX00 (where the X's will be various values as they are the top 16bits).
If you scan the file and all the data has 0 in the last two positions (hex) then it is a 16bit recording packed out to make 24 bits. (no data in the bottom 8 bits)

Pretty much what DaveinEL described in the previous posting...

bye for now

David

[Dimal]

G'day again mate...

Yes, am using a Hex Editor (have several to choose from actually) but I'm afraid I must be missing something basic in my understanding of how to read the data in the editor.

I've looked online for an explanation (with examples) but no luck there either; I'm afraid that what I see in the data tables doesn't easily translate from what you guys describe above. I can't see how to identify all relevant 24bits and whether the lower 8 are being used...

Oh well, will have to remain in the dark I guess....

Mal.

[DaveinEL]

I downloaded HexEdit v 1.2.1 but have never used it before so have as much knowledge as you.
Using HexEdit I open a file and get the default Hex view with 16 columns.
I go to View and choose binary.
I go to Tools and choose Options.
There I change Bytes per row to 3, press apply and then OK.
I am left with 3 columns of 8 digits each. Once you scroll down a little, the 24-bit Audacity files have the third column of only 0's, no 1,s.

I see that Audacity 2.0 Rc 4 is now available.

Version 2.0 is built on 1.3.14 which the Audacity info says will not do 24-bit so there is no surprise if Version 2.0 is the same.

I can't find any good info on version 2.0 in the Audacity forums. They're probably waiting for the final release before giving info.

[ripblade]

This thread has been most illuminating. I've learned quite a bit here myself thanks to those knowledgeable on the subject. While I don't use Audacity for recording I have an interest in determining the quality of the recordings with the recorder I use, Wave Corrector. It claims 24 bit capability but uses the MME API similar to Audacity, which I understand (perhaps incorrectly) is limited to 16 bits and 44.1 kHz sampling.

Looking at the 24 bit recordings made with the program using a hex editor as described above, the third column is randomly distributed ones and zeros. In order to produce the blank third column as described above I had to truncate the file to 16 bits then build it back out to 24 bits using dbPoweramp. Now I see a column full of zeros, just as described.

My question is: Is it possible to determine the value of information in the third column (assuming it isn't blank data)? Is it real data or is it merely noise, perhaps the result of dithering?

In attempting to answer this I made a new recording with the soundcard 'disconnected' from the program (this was easy to do because I haven't yet figured out how to connect them...it's a new card....but that's another matter...). What I have is a silent file (-90db) with neatly ordered bits - either all ones or all zeros consecutively - in the first 2 columns of each row, and randomly distributed bits in the 3rd column. It looks something like this:

00000000 00000000 00101001
11111111 11111111 01000100
11111111 11111111 10010100
00000000 00000000 00010110

The file illustrated is supposedly 24 bits. Is it in fact so? In this case, what is the content of the third column?

My apologies to the OP if this is viewed as derailing the thread. This seems to be the best place to learn about reading these files in a hex editor, and may be of some use regarding Audacity.

Thanks,

Glenn

[Dimal]

I downloaded HexEdit v 1.2.1 but have never used it before so have as much knowledge as you.
Using HexEdit I open a file and get the default Hex view with 16 columns.
I go to View and choose binary.
I go to Tools and choose Options.
There I change Bytes per row to 3, press apply and then OK.
I am left with 3 columns of 8 digits each. Once you scroll down a little, the 24-bit Audacity files have the third column of only 0's, no 1,s.

Excellent mate....

A great help and thank you very much. The various Hex Editors I tried wouldn't allow an option to reduce down to only 3 x 1-Byte Columns and only one of them allowed viewing the binary data directly. Has made life much easier, so thanks again....

Mal.

[hobbesetcalvin]

If you record with Audacity on Windows, it records in 16 bits altough the interface lets you believe otherwise. That's a shame.

The 2.0.0 release notes contains, almost lost within pages of notes:
"(Windows) Recording at 24-bit quality or higher isn't possible even with devices that support it due to current limitations in PortAudio. "
http://wiki.audacityteam.org/wiki/Release_Notes_2.0.0#Playback_and_Recording

I have lost time recording LPs with this software and wondering what was happening. I have tried Spin it Again and this time it works, and I can hear the difference.

Somme people say that 24 bit doesn't sound better that 16 and is a waste of space. Well that's true if the files are recorded with Audacity. There all 16 bits.