Size of aup3 versus aup files

Audacity Help Forum
1

I know that aup3 files contain all of the input audio so does that mean that I don’t need to keep the original input? Can I get the original input back out of audacity?

I record concerts in Stero 48000Hz 32bit WAV files. These files are about 1.5GB in size. Opening an aup file takes about 4mins, 301KB.
Opening an aup3 file takes about 4secs, 1.2GB.

I export the individual items as WAV files because too much is lost when CD quality is used. I’ve checked this with studio quality monitoring equipment.

Any suggestions?
Chris

2

Yes and Yes - BUT:. Although Audacity does represent its audio internally as 32-bit floating WAV, the .aup3 file structure itself is non-standard. Your files should always be backed up in some other file format, such as WAV.

3

IMO wav is the safest way to store your audio files :grin:

4

AUP and AUP3 project files are more complex and more “fragile” than WAV files.

You should back-up as WAV or FLAC immediately after recording. I doesn’t need to be 32-bits to preserve all of the information. It just has to match (or be higher than) the bit-depth of your interface (16 or 24-bits).

Depending on what you’re doing, you may not even need a project file. But it can serve as a backup if that’s the only backup you’ve got.

Audacity uses 32-bit floating-point internally. It makes processing “easier” and floating-point can go over 0dB so if you do anything that pushes the peaks over 0dB (like boosting the bass, for example) you won’t get clipping (distortion) as long as you lower the level before exporting.

And/or you can export as 32-bit floating point WAV but your “final production” shouldn’t go over 0dB because it can clip the listener’s DAC.

An AUP project contains multiple files and the actual audio isn’t in the AUP file.

There are 8-bits in a byte so one 32-bit sample is 4 bytes (8 for stereo).

(32-bits/8) x 48,000 x 2 channels = 384kB per second. (That doesn’t include any project overhead, or embedded artwork in a WAV file, etc.) That’s a bitrate of 3072kbps. (Usually we only “talk about” bitrate for compressed audio.)

1.2GB should be somewhere around 2-hours.

The “pro studio standard” is 24-bits/96Khz. But CD quality is generally better than human hearing.

A proper scientific, blind, ABX Test can be “humbling”. :wink: IF you can reliably hear a difference, you’ll have to listen VERY carefully.

…A good quality MP3 (lossy) can often sound identical to the uncompressed original (in a blind ABX test), or again, you’ll have to listen carefully to certain parts of the recording to hear the difference. (A low-quality, low-bitrate, MP3 can sound pretty bad!)

The exception could be a floating-point file that goes over 0dB and then the integer copy would clip.

5

Thank you all for your replies. As my main use of audacity is to split a show down into tracks I’ll keep the original WAV and tracks then delete the project.
I’m a professional musician and most of my recordings are of a pipe organ which I myself play from time to time (for the last 50 odd years). Setting recording levels is easy as there is a limit as to how loud the instrument can be. I can record at 96kHz but have nor yet done so. The hall has a good sound system so checking in the auditorium to note differences in quality is easy. The organ has a MIDI system so can reproduce any performance exactly. This can then be compared with the playback of different format digital recordings.
For the record I use a Tascam DR-100 Mk3 recorder and the organ details are on victoriahall-organproms.co.uk.
Thanks again,
Chris