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Topic: Edit MP3 then convert to FLAC. Quality Loss? (Read 3695 times) previous topic - next topic
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Edit MP3 then convert to FLAC. Quality Loss?

I have a bunch of long EDM songs already in MP3 320 format. What I'm looking to do is edit some of them down to a shorter length in Audacity and add a fade out. I know that if I export the edited audio as MP3 then it's obviously going to be re-encoded and there will be quality loss, but what if I export it as FLAC? Based on what I already know, I wouldn't think there would be any quality loss since I'm not re-encoding the file and FLAC is just a lossless compression of a WAV.

I know I'll probably end up with a file that is possibly bigger in size than the original longer MP3, but I can live with that. My main goal is just a shorter song without quality loss.

Thanks for anything you might be able to share.

Edit MP3 then convert to FLAC. Quality Loss?

Reply #1 –
Yes, saving the result as FLAC will not lose quality compared to the MP3. However, if you're saving to 16-bit, be sure that Audacity is set to dither on export. (I prefer the "Triangle" option.)

You also might want to use the Amplification effect to normalize the song at 0.00 dB or less, to prevent the FLAC from clipping due any intersample peaks that might have been introduced by the MP3 encoding.

Edit MP3 then convert to FLAC. Quality Loss?

Reply #2 –
Quote from: Rick540 on
I have a bunch of long EDM songs already in MP3 320 format. What I'm looking to do is edit some of them down to a shorter length in Audacity and add a fade out. I know that if I export the edited audio as MP3 then it's obviously going to be re-encoded and there will be quality loss, but what if I export it as FLAC? Based on what I already know, I wouldn't think there would be any quality loss since I'm not re-encoding the file and FLAC is just a lossless compression of a WAV.


In principle, there is the issue that a fixed-point PCM file cannot contain an mp3 signal exactly. Of course, up to the (dithered, if you like) roundoff-errors beyond the resolution (of, say, 16 bits) it can.
In practice, you should look for volumes that are too way off. The conversion to PCM should not clip, which could happen if the peak of the file is above the full digital "1", you can scan for peaks using e.g. a ReplayGain scanner; if there is an insane peak it is often an artifact of a damaged file or a bad encoder, and that should likely be addressed by inspecting the waveform. If the volume is extremely low, you may want to import to 24 bits, peak-normalize, and then export to 16 bits.

But if fadeout in 1.5 dB steps will be OK with you, I think it is possible to do what you want in mp3directcut without re-encoding.

Edit MP3 then convert to FLAC. Quality Loss?

Reply #3 –
In the past, I have used a program called mp3DirectCut. It lets you cut and past the mp3 file without decompressing the  mp3. It is a free program and can be found at: http://mpesch3.de1.cc/mp3dc.html


Glass half full!

Edit MP3 then convert to FLAC. Quality Loss?

Reply #4 –
Regarding saving as much audio from transcoding while also creating fade-outs without 1.5dB steps...

https://www.hydrogenaud.io/forums/index.php...st&p=909340

...but for mp3 instead of aac.

Can someone provide a technical reason as to why this can't be accomplished?