I wanted to use Audacity to ‘trim’ the end of a 3-hour DJ mix.
The original WAV file is 1.77GB. Upon editing the file to fade out at the end, and then exporting it as a WAV file, the resultant WAV file is 3.57GBs!
Why does this happen and how do I prevent it? Ideally, the exported WAV file should be the same size as the original imported file if not slightly smaller due to loss of data in encoding. When I export the edited mix as an MP3, it amounts to a 411MB file. This makes sense given how much is lost upon encoding to MP3, but why a BIGGER WAV file when exporting as a WAV file?? Surely that means there’s a whole bunch of ‘noise’ as data in the exported WAV file. I thought WAV files were not subject to compression and therefore there would be no reason the exported file is larger, unless more ‘noise’ data has been added somehow.
What am I missing? What settings should I use to enable the exported WAV file to be the same or similar size to the original WAV file?
or from 8-bit to 16-bit, or from 16-bit to 32-bit or was the original file not actually WAV format?
The default format when Exporting from Audacity as WAV is 16-bit WAV (mono or stereo depending on whether the project is mono or stereo).
If you know there are 8-bits in a byte (and if you know the format details and playing time) you can calculate the file size for uncompressed files.
For example, 16-bit stereo is 2 bytes per sample x 2-channels so that’s 4 bytes per (stereo) sample. At 44.1kHz, that’s 176,400 bytes per second.
For compressed files you need to know the (average) bit rate. The bit rate is normally given in kbps = kilo_bits_ per second so you can divide by 8 to get kilo_bytes_ per second.
(If there is embedded artwork, of course that adds to file size.)