Hello. I have a 320kbps audio file that I am editing losslesly. Should I save it as FLAC or 320kbps if I wish not to lose further quality?
Repeated mp3 encoding, even with the same or better quality than in the preceding step, does not leave the audio data unchanged. Thus, the answer is “FLAC” (or any other lossless format).
WAV (Microsoft) 16-bit is the go-to format for production. The bitrate is 1411. The only shortcoming is the tiny dither signal that Audacity adds to exports to avoid filter and effects errors from accumulating. You may not want to, but you can turn that off.
Audacity internally works at 32-floating (not 16-bit) in order that effects and filters don’t produce distortion. The only time you may experience distortion is if you create a show that won’t fit in conventional file formats at export.
Pay attention to the bouncing sound meter to make sure your show doesn’t go over 0dB. If you have multiple tracks, you can Tracks > Mix > Mix and Render to a New Track. Audacity will create a fresh track exactly how your show is going to appear when you export a sound file and Audacity creates a mix for you.
Koz
steve has replied to the same question I had, only about editing a FLAC file and not a 320kbps file, this:
Does his reply apply in this case too, or is it different because it’s a 320kbps file and not a FLAC originally?
I should have mentioned that by “editing losslesly” the 320kbps file I meant what steve described in his reply I quoted; “cut edits and no processing”.
Audacity does not operate directly on audio files. When you “open” an MP3 file, Audacity copies the data into the Audacity project, and then you can edit and process the copied data. Audacity always works on a copy of the data, regardless of the original audio file format. Therefore the same rule applies: If you only perform cut / copy / paste / delete type “edits”, and no “processing”, then Audacity can do that entirely losslesly by temporarily turning off “dither”.
Having said that, the “damage” caused by leaving dither enabled is virtually insignificant. If there is any background noise in the original audio, then that is likely to totally drown out the noise created by dither. The “damage” caused by accidentally leaving dither disabled (when it should be enabled) is likely to be greater than if you leave dither enabled when it could be disabled. It is very rare that I ever disable dither because the theoretical benefit is usually not worth the effort.
Thank you, everyone. 
So for now, whether the file I opened is lossy or lossless, once done editing I should save it as FLAC?
To avoid sound quality loss when exporting, export in a “lossless” format.
Audacity supports the following lossless formats:
WAV
AIFF
FLAC
16-bit WAV is the most widely supported audio format - just about everything supports 16-bit WAV, though few programs support “metadata” tags in WAV files.
FLAC has the benefit that the file size is smaller than WAV or AIFF, and it has very good support for metadata tags, but FLAC is less widely supported than WAV of AIFF.
On Windows, support for FLAC in Windows Media Player (and many other audio players) by installing the “Directshow Filters” from Xiph: https://www.xiph.org/dshow/
By ‘supported’, do you mean playable in media players?
When I Export Audio and select FLAC, what Level and Bit Depth should I select? What difference do they make?
As your original was an MP3, I’d recommend “16-bit”. The 24-bit option would give a bigger file size but the sound quality would be no better.
The 24-bit option only really has an advantage if the original is 24-bit or better.
The “Level” refers to how hard the encoder tries to shrink the file. High numbers may produce slightly smaller files at the expense of slower processing. The default “5” is generally a good setting.
Noted
Now excuse my ignorance, but I also have plenty of FLAC files. How can I tell if those are 24-bit or better? (so when I edit them with Audacity I know whether to export as 16-bit or 24-bit)
In my opinion, it doesn’t really matter. 16-bit is the same as is used by audio CDs. Unless you intend to always listen in a professional studio environment, it will not be possible to hear the difference between 16-bit and 24-bit.
The only difference between 16-bit and 24-bit is the level of the digital noise floor. For 16-bit, the digital noise floor is extremely low - typically much lower than other noise sources that will be present. For 24-bit, the digital noise floor is even lower.
One benefit of using 24-bit FLAC is that you never need to change the dither settings - just leave it set to “shaped” all of the time. The reason being, that dither noise for 24-bit is totally inaudible.
Alright. Thank you very much steve and everyone else for your elaborate answers. What a nice community
Last question if I may, is there a difference if I File>>Export >>Export as WAV then from that window select FLAC or if I File>>Export>>Export Audio then from that window select FLAC? Or is it the same?
This would be a grand time to find The Goal. Why are we doing this? Who gets the files? I would not, for example, send a FLAC file to a client in this lifetime, unless they specifically asked for one.
Also, if you’re skating that close to running out of storage, you’re going to have a lot more problems than compression bitratres.
There are editor programs which will do simple editing (cutting) without impacting the quality of the file. Those are highly recommended if your job calls for that kind of editing.
As above, compression is a time bomb. If you have a highly compressed MP3 music file, you can edit it in Audacity and export it as a perfect quality WAV with little or no damage. However, if you then edit the WAV file and export an MP3, original compression rules apply and your music will likely turn to honky, bubbly trash. The WAV step in the middle doesn’t magically get rid of the compression distortion.
Koz
Both the same.
The “Export as WAV” option is just a shortcut to “File>>Export>>Export Audio then from that window select WAV”.
Steve, I’m sorry for bumping, as well as troubling with a subject you’ve so elaborated on already, but if for example I have an audio file of 192kbps and I do simple edits on Audacity, what is ideal saving as if I don’t want to loss quality but also not to ‘pointlessly’ increase the file size? I mean- Is there a point to save it as 320kbps or even FLAC if it was 192kbps from first place (since that would double or even triple the file size)? Or if I save it as 192kbps, there will be no quality loss?
Encoding in a “lossy” format such as MP3, WMA, OGG, M4A,… will always lose some audio quality. Higher bit-rates minimize the loss of quality.
If you need to use a lossy format, then it’s up to you to decide how much loss is acceptable to you. The lower the bit-rate, the greater the losses.
The standard recommendation, is to always work with lossless audio formats (such as WAV), and only encode to a lossy format (if required), as the final step of the production (after saving a backup copy in a lossless format).
Oh. I was under the impression there would only be quality loss if it was originally a lossless and it is saved as something lower than that. I didn’t know that if it was ‘low’ from first place and saved as the same, there would still be loss.
As always, thanks.
That’s the thing that catches lots of people out.
Encoding in a lossy format is like making a photocopy. The quality of a photocopy is always a bit lower than the original. A photocopy from the original may “look” identical to the original, but if you make a photocopy of a photocopy of a photocopy… then after a few “generations”, the losses become apparent, because of the cumulative effect of the losses.