Non-destructive MP3 editing

Plug-in hosts and other software applications discussion
publicradio
KVRist
305 posts since 23 Mar, 2008

Post Mon Jan 20, 2020 1:07 pm

A few years ago, I stopped recording my source material in wav. I use flac instead, and it works fine for me. However, my field recorder only records in wav, or MP3 — though I can record at 320kbps.

I like having field recordings in MP3 because I can store and organize them as easily as my other MP3s. My only hesitation is that I'll lose sound quality if I ever try to use them in a podcast, a song, or some other purpose.

So I have two questions:
  • Is there a recommended program for editing MP3s in a non-destructive way? I use Linux, and Audacity is destructive. If I open an mp3 to trim it, the program will decode it, then re-encode it. FFMPEG is a linux library that does non-destructive MP3 editing, but I have yet to find a good GUI for it. Furthermore, I'd like to fade the ends of my recordings, and I don't know if there's any way to do this withoug re-encoding.
  • How much damage is actually done if I'm importing MP3s at 320k, tweaking them (normalizing, compressing, editing), then re-encoding as a 320k MP3? I suspect audio compression would expose audible data compression worst of all, but again, I don't know how perceptible this is at 320k.

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mladi
KVRian
881 posts since 14 Apr, 2016 from Germany

Re: Non-destructive MP3 editing

Post Mon Jan 20, 2020 1:18 pm

This is a good little app without decoding: http://mp3splt.sourceforge.net/mp3splt_page/home.php
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No_Use
KVRAF
2421 posts since 13 Mar, 2004

Re: Non-destructive MP3 editing

Post Mon Jan 20, 2020 1:22 pm


publicradio
KVRist
305 posts since 23 Mar, 2008

Re: Non-destructive MP3 editing

Post Mon Jan 20, 2020 1:39 pm

Thanks mladi, mp3splt was the best thing I could find for native linux.

No_Use, mp3DirectCut looks like the best solution. Even though it's not native linux, it looks like the author develops with Wine in mind. And the fact that you can normalize and fade without re-encoding makes this a great option. Thanks a lot.

Maybe someone can speak to the other question: is it a bad idea to work in 320 MP3s? I would never record for music this way, because of how I process that kind of audio (for instance, taking a line-in electric guitar recording, then running it through a stompbox emulator, then adding compression and tape saturation would start to bring out those compression artifiacts). But if you're recording found sounds, and maybe you want to make a sound collage or something, and you're only processing and re-encoding once, is it still a mistake to work with MP3s?

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CrystalWizard
KVRian
1044 posts since 10 Jul, 2008 from Orbit Sol III

Re: Non-destructive MP3 editing

Post Mon Jan 20, 2020 2:01 pm

I would recommend recording in a lossless higher quality format. Not sure what “field” it is that you are recording in :D but 24bit/44.1 or 48k is going to sound better especially after editing. When i record birds or bugs i go to 96k, and most people can hear the difference (on a good system in my testing lab.) :)

You can always batch file convert them to mp3 later for convenience.
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toine6
KVRian
1309 posts since 29 Mar, 2002 from Salt Lake City, Utah - U.S.A.

Re: Non-destructive MP3 editing

Post Mon Jan 20, 2020 2:32 pm

One should always aim to work at the best quality if they can, only converting down as the last step for the format needed. But if it doesn't bother you, and it's not practical, and it mostly sounds fine, then that's your call. It's not ideal, but don't let it stop you from working or releasing projects. Sometimes convenience is inspiring and perfectionism is debilitating. It seems like sometimes people are afraid of things they can not hear, and that some golden eared police will expose them, and toss them in audiophile jail.

Just general thoughts, as I have no knowledge of non-destructive mp3 editing to offer.

publicradio
KVRist
305 posts since 23 Mar, 2008

Re: Non-destructive MP3 editing

Post Mon Jan 20, 2020 2:51 pm

Thanks for the replies. CrystalWizard, I usually record at 24bit/48k. Maybe I should record at 96k for things like bugs. I've read that if you record at 96, then downsample to 48, the quality is still better — more gets picked up on the recording.

I think if I had a field recording, and there was something interesting in there, but barely perceptible — like a distant conversation — the best chance of isolating and enhancing that would be with a lossless file.

Considering .flac will bring the file size down 40%—50%, and that you can tag, organize and play them the same as MP3s, then it sounds like the best move is to record 24bit / 96k .wav files, then batch convert them to flac at the same sampling and bitrate.

zacha
KVRist
71 posts since 14 Oct, 2018

Re: Non-destructive MP3 editing

Post Mon Jan 20, 2020 3:32 pm

Keep in mind also that I suspect .mp3 compression will be filtering out sounds above 15kHz or so

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CrystalWizard
KVRian
1044 posts since 10 Jul, 2008 from Orbit Sol III

Re: Non-destructive MP3 editing

Post Mon Jan 20, 2020 3:43 pm

publicradio wrote:
Mon Jan 20, 2020 2:51 pm

I think if I had a field recording, and there was something interesting in there, but barely perceptible — like a distant conversation — the best chance of isolating and enhancing that would be with a lossless file.

Considering .flac will bring the file size down 40%—50%, and that you can tag, organize and play them the same as MP3s, then it sounds like the best move is to record 24bit / 96k .wav files, then batch convert them to flac at the same sampling and bitrate.
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BertKoor
KVRAF
11484 posts since 8 Mar, 2005 from Utrecht, Holland

Re: Non-destructive MP3 editing

Post Tue Jan 21, 2020 12:13 am

zacha wrote:
Mon Jan 20, 2020 3:32 pm
Keep in mind also that I suspect .mp3 compression will be filtering out sounds above 15kHz or so
I've done some tests in the past, but this is only true for lower bitrates. Lower than 128kbps iirc. 320kbps should go all the way up to 22 kHz. But it may depend on the encoder.

What I would do, is keep the original .mp3 as archive and convert to WAV as first step whenever you're actually using it.
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CrystalWizard
KVRian
1044 posts since 10 Jul, 2008 from Orbit Sol III

Re: Non-destructive MP3 editing

Post Tue Jan 21, 2020 5:23 am

Uh, no, i would suggest opposite. Record in wav, edit in wav, then degrade into mp3. This way you have the quality source, you can edit the quality, then just mp3 what you need to be small files. With the cost of digital storage these days there is no reason to skimp on quality.
gadgets an gizmos...make noise
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superscan
KVRist
210 posts since 2 Aug, 2013 from USA

Re: Non-destructive MP3 editing

Post Tue Jan 21, 2020 5:40 am

Check out https://rogueamoeba.com/fission/ Mac Only...

Ploki
KVRAF
1549 posts since 17 Dec, 2009

Re: Non-destructive MP3 editing

Post Tue Jan 21, 2020 12:59 pm

publicradio wrote:
Mon Jan 20, 2020 2:51 pm
Thanks for the replies. CrystalWizard, I usually record at 24bit/48k. Maybe I should record at 96k for things like bugs. I've read that if you record at 96, then downsample to 48, the quality is still better — more gets picked up on the recording.

I think if I had a field recording, and there was something interesting in there, but barely perceptible — like a distant conversation — the best chance of isolating and enhancing that would be with a lossless file.

Considering .flac will bring the file size down 40%—50%, and that you can tag, organize and play them the same as MP3s, then it sounds like the best move is to record 24bit / 96k .wav files, then batch convert them to flac at the same sampling and bitrate.
1) Technically if you downsample 96 KHz to 48 KHz you will end up with the same 23.X KHz hard limit... So the ending result will not have more information than as if you recorded at 48 KHz.

2) MP3 at 320kbps doesn't truncate everything below a certain threshold, but a lossless file would generally be better for that purpose yes.

3) Yes. I sometimes do that with my logic projects - convert the whole audiobin to lossless CAF for archiving.

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