Constant Bit Rate Export Problem

I think I’ve been doing this for about 5 years or so. I always did this in Windows and in the last year or so I started doing it in Linux.

Currently I’m running Linux Mint 17.3 xfce 64 bit. I’m running Audacity 2.1.2. Last night I upgraded it in hopes that it would somehow solve my problem. It did not. Headphones I use is the Koss UR40. I use the Sandisk Sansa Clip + and I have rockbox installed.

This all started several weeks ago.

Usually when I buy mp3s I download them from Amazon. Then Unzip them and after that I load all of them up into Audacity. Next I export them as a 128 constant bit rate files. I make all of them stereo. Over all of these years I’ve never touched any of the encoder settings. I don’t make it go faster or slower. Everything is on default.

After I get done doing that I load all my mp3s into a tag program. If it’s windows then I used Mp3tag, and if it’s in Linux I use Puddletag. After getting the tags the way I like them, I just copy and paste the songs onto my player.

I want whoever reads this to realize that I understand that the higher the bit rate = higher quality and the lower bit rate = lower quality. But through many listenings I had decided that 128 is alright for the equipment and the condition of my hearing. (Whatever condition my ears might be in)

I listen to mainly Hard Rock, Metal, Alternative, and some Celtic music.

The other day I had downloaded two new albums by two bands I am very familiar with. When I played both bands back, something just didn’t feel right too me. But I figured it must just be the way these guys decided to do things in the studio. But two days ago I downloaded some new stuff and when I was listening to them. I realized that my hearing wasn’t feeling right. I tried to lower the volume, and I even tried to change the EQs but made anything sound better. Finally I did something I don’t normally do. I went back to Amazon and downloaded the originals and put them directly onto the Mp3 player. When I played those back everything sounded like it should.

I got out my Windows laptop, and I used Audacity to remake one 128 version of one song. And I did the same thing on the Linux mint machine. Then lined all three songs up and compared. Then I took the same three I had made and did the same on my other computer. What I come up with is, the 128 made on the Windows computer sounded just a little closer to the original then the one made on the Linux computer.

All year I’ve been using the Linux Mint machine with Audacity to make the conversion from whatever bit rate down to 128 and everything has been fine, up until now.

Is there anything I can check, or re install that could solve what is going on?

What are the exact MP3 settings you are using?

Note that MP3 encoding reduces the quality each time it is encoded, so encoding a perfect WAV file will give a certain degree of quality, but (re)-encoding an MP3 will give lesser quality (like a photocopy of a photocopy). So the quality of the MP3 that you end up with depends on the quality of the file you are encoding. It may be worth checking to see what the exact format of these songs was before you encoded. MediaInfo (available in the repository) can tell you that. Also, check that the format of the files that you have encoded are as you think they are.

Stereo, 44100Hz 32-bit float, Constant 128 kbps, Channel Mode Stereo. Did I miss anything you want me to tell you?

I understand what your saying about photocopy of a photocopy. But I’ve been doing it this way for a good 5 years, and never ran into this issue before. Both 128’s were made from the original just on different OSes.


Original
General
Complete name : /media/gregory/03VIDEOS/Testing Audio/01 280- The Dogma of Chalcedon.mp3
Format : MPEG Audio
File size : 7.43 MiB
Duration : 3mn 40s
Overall bit rate mode : Variable
Overall bit rate : 280 Kbps
Copyright : 2016 Endtime Productions
Cover : Yes
Cover type : Cover (front)
Cover MIME : image/jpeg

Audio
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Mode : Joint stereo
Mode extension : MS Stereo
Duration : 3mn 40s
Bit rate mode : Variable
Bit rate : 280 Kbps
Channel(s) : 2 channels
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 7.36 MiB (99%)

Made on Linux Mint
General
Complete name : /media/gregory/03VIDEOS/Testing Audio/02 128 - (Linux Mint) The Dogma of Chalcedon.mp3
Format : MPEG Audio
File size : 3.36 MiB
Duration : 3mn 40s
Overall bit rate mode : Constant
Overall bit rate : 128 Kbps
Writing library : LAME3.99r
Band : Crimson Moonlight
Copyright message : 2016 Endtime Productions

Audio
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Duration : 3mn 40s
Bit rate mode : Constant
Bit rate : 128 Kbps
Channel(s) : 2 channels
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 3.36 MiB (100%)
Writing library : LAME3.99r
Encoding settings : -m s -V 4 -q 3 -lowpass 17 -b 128

Made on Windows7
General
Complete name : /media/gregory/03VIDEOS/Testing Audio/03 128- (Windows)- The Dogma of Chalcedon.mp3
Format : MPEG Audio
File size : 3.36 MiB
Duration : 3mn 40s
Overall bit rate mode : Constant
Overall bit rate : 128 Kbps
Writing library : LAME3.99r
Copyright message : 2016 Endtime Productions
Band : Crimson Moonlight

Audio
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Duration : 3mn 40s
Bit rate mode : Constant
Bit rate : 128 Kbps
Channel(s) : 2 channels
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 3.36 MiB (100%)
Writing library : LAME3.99r
Encoding settings : -m s -V 4 -q 3 -lowpass 17 -b 128

Thanks for the comprehensive info. From that I would expect the re-encoded MP3s to sound identical (when played on the same playback equipment).
So to recap, the problem that you’re reporting is that they don’t sound the same - the version made on Mint 17.3 sounds worse than the version made on Windows 7 (?)

I don’t have Mint but I do have Debian xfce, so if you can upload the tracks somewhere (too big for the forum, so perhaps dropbox, SendSpace or some other free file sharing site), I can test on my machine to see if I get the same problem.

I presume that if you export (from Mint) in any other format, the problem does not occur?

LAME 3.99 encompasses different versions http://lame.cvs.sourceforge.net/viewvc/lame/lame/doc/html/history.html. Although nominally there are no bug fixes between LAME 3.99 versions that seem to affect quality, I don’t think you can make comparisons unless you are actually using the same version of LAME on both machines.

Audacity on Windows will tell you in Libraries preferences what version of LAME is in use. Assuming Libraries preferences is removed on your Linux Mint version of Audacity, you may have to look at Synaptic or elsewhere to find out more.

What about decoding? Do the MP3’s sound the same on Windows and Linux after you import them into Audacity before you encode them?


Gale

I haven’t tried to export into any other format. Even though doing that would be interesting to see what the results would be… For me as a user it would be counter productive. My mp3 players only playback the mp3 and wmv formats. Since I already have close to 7,000 songs in the mp3 128 format, I’d rather just reinstall a different OS to see if that fixes it. Currently I don’t have a dropbox or a sendplace. If I was going to do that for you, I would need a non-copyrighted song in a very high bit rate sent to me. That I could experiment with. Do you have anything like that in your collection?

Currently the only things I can think of that might have changed things: 1) I tried to install ardour4 2) I tried to remover adobe flash and when it was removed it took the mint-meta-codecs off with it. (I’ve since tried to put those two back on the machine and didn’t notice any change) and 3) some kind of update that changed the encoder a little.

I’ve been thinking about changing the OS over to either Mint 18 xfce or MX15 a debian distro with the xfce desktop. If I can use either one depends on if I can get the printer driver to install. The last time I tried Linux Lite 3.0 (Based on Ubuntu 16.04) I couldn’t make my printer work. The thing about Mint 18 is it is also based on Ubuntu 16.04 and I haven’t tried MX15 on that machine. My prediction is changing the OS would fix my problem with Audacity but my printer won’t work with Mint 18. I think I will grab an extra hard drive and load it up with with one and see what happens.