mp3 magically becoming m4a?

[rickyraccoon]

All right this is a weird one, and I have no idea if this is the right forum, if there are any right forum for it here, for that matter.

Running MX-21.3 64-bit on an SSD that's shared with Windows 10.

So I had a collection of mp3s, ripped from my CD collection over the years. So far so good. I keep them on this terabyte HDD I have as a data disk, in a EXT4 partition that Windows isn't privy to- I don't run any funky utilities on Windoze to access my EXT4 partitions.

Well I dumped a bunch of music onto a SD card to play in my car and my mechless wasn't finding all of my mp3s, because lo and behold, many of them are now m4a. And I have no freaking idea what I did to do that. I've never purposely converted my music to m4a, I have no reason to. Now I know gremlins didn't sneak onto my computer while I was fast asleep, so I must have inadvertently done something, but I have no clue what. None at all. What on Earth could I possibly have done within MX to suddenly make half- or more- of my ripped CDs Mpeg-4? I have no idea when this even happened. It's just like, wait. Why are my files not mp3? And I started to look, and a darn many of them are like that. But not all. I've moved files around a lot over the past few years from one hard drive to another but what? how? I don't know!

Anyway if anyone has a clue to this, thanks. Other than just telling me I'm going mad, which is what it feels like. I've never heard of a file spontaneously changing formats and I don't believe that happened now. So what the heck did I do?

It's not all lost- I should have backups somewhere, but still I'd like to know what the heck I did, This is maddening, wondering how this happened.

FWIW, my system info

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System:    Kernel: 5.10.0-20-amd64 [5.10.158-2] x86_64 bits: 64 compiler: gcc v: 10.2.1 
           parameters: BOOT_IMAGE=/boot/vmlinuz-5.10.0-20-amd64 
           root=UUID=<filter> ro quiet splash 
           init=/lib/systemd/systemd 
           Desktop: Xfce 4.18.0 tk: Gtk 3.24.24 info: xfce4-panel wm: xfwm 4.18.0 vt: 7 
           dm: LightDM 1.26.0 Distro: MX-21.3_x64 Wildflower September 18  2022 
           base: Debian GNU/Linux 11 (bullseye) 
Machine:   Type: Desktop Mobo: ASRock model: N3150M serial: <filter> 
           UEFI-[Legacy]: American Megatrends v: P1.10 date: 06/02/2015 
CPU:       Info: Quad Core model: Intel Celeron N3150 bits: 64 type: MCP arch: Airmont family: 6 
           model-id: 4C (76) stepping: 3 microcode: 368 cache: L2: 1024 KiB 
           flags: lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 12800 
           Speed: 2080 MHz min/max: 480/2080 MHz Core speeds (MHz): 1: 2080 2: 2080 3: 1082 
           4: 1162 
           Vulnerabilities: Type: itlb_multihit status: Not affected 
           Type: l1tf status: Not affected 
           Type: mds mitigation: Clear CPU buffers; SMT disabled 
           Type: meltdown mitigation: PTI 
           Type: mmio_stale_data status: Unknown: No mitigations 
           Type: retbleed status: Not affected 
           Type: spec_store_bypass status: Not affected 
           Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer sanitization 
           Type: spectre_v2 mitigation: Retpolines, IBPB: conditional, IBRS_FW, STIBP: disabled, 
           RSB filling, PBRSB-eIBRS: Not affected 
           Type: srbds status: Not affected 
           Type: tsx_async_abort status: Not affected 
Graphics:  Device-1: Intel Atom/Celeron/Pentium Processor x5-E8000/J3xxx/N3xxx Integrated Graphics 
           vendor: ASRock driver: i915 v: kernel bus-ID: 00:02.0 chip-ID: 8086:22b1 class-ID: 0380 
           Device-2: NVIDIA GK208 [GeForce GT 635] driver: nvidia v: 470.161.03 bus-ID: 02:00.0 
           chip-ID: 10de:1280 class-ID: 0300 
           Display: x11 server: X.Org 1.20.11 compositor: xfwm4 v: 4.18.0 driver: 
           loaded: modesetting,nvidia unloaded: fbdev,nouveau,vesa alternate: nv display-ID: :0.0 
           screens: 1 
           Screen-1: 0 s-res: 1920x1080 s-dpi: 96 s-size: 508x286mm (20.0x11.3") 
           s-diag: 583mm (23") 
           Monitor-1: HDMI-0 res: 1920x1080 hz: 60 dpi: 92 size: 531x299mm (20.9x11.8") 
           diag: 609mm (24") 
           OpenGL: renderer: NVIDIA GeForce GT 635/PCIe/SSE2 v: 4.6.0 NVIDIA 470.161.03 
           direct render: Yes 
Audio:     Device-1: Intel Atom/Celeron/Pentium Processor x5-E8000/J3xxx/N3xxx Series High 
           Definition Audio 
           vendor: ASRock driver: snd_hda_intel v: kernel bus-ID: 00:1b.0 chip-ID: 8086:2284 
           class-ID: 0403 
           Device-2: NVIDIA GK208 HDMI/DP Audio driver: snd_hda_intel v: kernel bus-ID: 02:00.1 
           chip-ID: 10de:0e0f class-ID: 0403 
           Sound Server-1: ALSA v: k5.10.0-20-amd64 running: yes 
           Sound Server-2: PulseAudio v: 14.2 running: yes 
Network:   Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: ASRock 
           driver: r8169 v: kernel port: c000 bus-ID: 03:00.0 chip-ID: 10ec:8168 class-ID: 0200 
           IF: eth0 state: up speed: 1000 Mbps duplex: full mac: <filter> 
Drives:    Local Storage: total: 1.27 TiB used: 435.42 GiB (33.6%) 
           SMART Message: Unable to run smartctl. Root privileges required. 
           ID-1: /dev/sda maj-min: 8:0 vendor: Kingston model: SA400S37120G size: 111.79 GiB 
           block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s type: SSD serial: <filter> 
           rev: B1D1 scheme: MBR 
           ID-2: /dev/sdb maj-min: 8:16 vendor: A-Data model: SU630 size: 223.57 GiB block-size: 
           physical: 512 B logical: 512 B speed: 6.0 Gb/s type: SSD serial: <filter> rev: 129a 
           scheme: MBR 
           ID-3: /dev/sdc maj-min: 8:32 vendor: Hitachi model: HUA722010CLA330 size: 931.51 GiB 
           block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s type: HDD rpm: 7200 
           serial: <filter> rev: A3EA scheme: MBR 
           ID-4: /dev/sdd maj-min: 8:48 type: USB vendor: SanDisk model: Cruzer Force 
           size: 28.65 GiB block-size: physical: 512 B logical: 512 B type: N/A serial: <filter> 
           rev: 1.00 scheme: MBR 
           SMART Message: Unknown USB bridge. Flash drive/Unsupported enclosure? 
           ID-5: /dev/sde maj-min: 8:64 type: USB vendor: Toshiba model: TransMemory 
           size: 1.92 GiB block-size: physical: 512 B logical: 512 B type: N/A serial: <filter> 
           rev: 5.00 scheme: MBR 
           SMART Message: Unknown USB bridge. Flash drive/Unsupported enclosure? 
Partition: ID-1: / raw-size: 215.75 GiB size: 211.31 GiB (97.94%) used: 32.58 GiB (15.4%) fs: ext4 
           dev: /dev/sdb1 maj-min: 8:17 
Swap:      Kernel: swappiness: 15 (default 60) cache-pressure: 100 (default) 
           ID-1: swap-1 type: partition size: 7.81 GiB used: 0 KiB (0.0%) priority: -2 
           dev: /dev/sdb2 maj-min: 8:18 
Sensors:   System Temperatures: cpu: 38.0 C mobo: N/A gpu: nvidia temp: 48 C 
           Fan Speeds (RPM): N/A gpu: nvidia fan: 19% 
Repos:     Packages: note: see --pkg apt: 2169 lib: 1112 flatpak: 0 
           No active apt repos in: /etc/apt/sources.list 
           Active apt repos in: /etc/apt/sources.list.d/brave-browser-release.list 
           1: deb [arch=amd64] https://brave-browser-apt-release.s3.brave.com/ bullseye main
           Active apt repos in: /etc/apt/sources.list.d/debian-stable-updates.list 
           1: deb http://deb.debian.org/debian bullseye-updates main contrib non-free
           Active apt repos in: /etc/apt/sources.list.d/debian.list 
           1: deb http://deb.debian.org/debian bullseye main contrib non-free
           2: deb http://security.debian.org/debian-security bullseye-security main contrib non-free
           Active apt repos in: /etc/apt/sources.list.d/google-chrome.list 
           1: deb [arch=amd64] https://dl.google.com/linux/chrome/deb/ stable main
           Active apt repos in: /etc/apt/sources.list.d/google-earth-pro.list 
           1: deb [arch=amd64] http://dl.google.com/linux/earth/deb/ stable main
           Active apt repos in: /etc/apt/sources.list.d/microsoft-edge.list 
           1: deb [arch=amd64] https://packages.microsoft.com/repos/edge/ stable main
           Active apt repos in: /etc/apt/sources.list.d/mx.list 
           1: deb http://mirrors.rit.edu/mxlinux/mx-packages/mx/repo/ bullseye main non-free
           Active apt repos in: /etc/apt/sources.list.d/opera-stable.list 
           1: deb https://deb.opera.com/opera-stable/ stable non-free #Opera Browser (final releases)
           Active apt repos in: /etc/apt/sources.list.d/vivaldi.list 
           1: deb [arch=amd64] https://repo.vivaldi.com/stable/deb/ stable main
Info:      Processes: 232 Uptime: 2h 20m wakeups: 0 Memory: 7.63 GiB used: 1.83 GiB (23.9%) 
           Init: systemd v: 247 runlevel: 5 default: 5 tool: systemctl Compilers: gcc: 10.2.1 
           alt: 10 Client: shell wrapper v: 5.1.4-release inxi: 3.3.06 
Boot Mode: BIOS (legacy, CSM, MBR)

[h3kt0r]

Don't you know someone which owns an ipod and has your account password ?

[davidy]

Just use Sound Converter. It'll fix it in a flash.

[rickyraccoon]

Don't you know someone which owns an ipod and has your account password ?

Password to... my MX account? Nope, and not an Apple anything in the house.

Just use Sound Converter. It'll fix it in a flash.

I'll remember that, thanks. Or... I'll just re-rip. Or see if an old HDD kicking around has the originals. I mainly just wanted to know if someone knew how this could happen in Linux.

I've circumvented the issues with an old phone and a audio patch cable. Besides which, I can put a far larger SD card in an old phone, than the car stereo will reliably accept. It's this cheap little Jenson mechless unit and only takes up to 8GB anyway. Ehh, an old Windows Phone does just fine with Groove Music and plays the format, so I use it now.

Still, it's aggravating. I did not do this to my files. I have no idea when it happened, or how it happened. I use Clementine and VLC to listen to stuff, and occasionally Qmmp. Windows isn't hacked to access my Linux partitions. I just have no clue where or when mp3s disappeared and m4as appeared. I guess I'll just have to put it down to Fae folk or imps or gremlins or something.

[figueroa]

Categorically, nothing will do this without you giving permission/access, even if you didn't do it on purpose. You seem to know that. So, maybe they were never MP3 files. Or, as you wrote, "I must have inadvertently done something.

Can you prove to yourself that they were originally MP3 files, i.e. chasing down backups or other copies? Sort the files by date and see if they have anything in common that way. Maybe they are not just ripped files, but maybe include downloads? I'll be interested in a conclusion to this if you find one.

[baldyeti]

Perhaps the filename extension (.mp3) was incorrect and your car's audio player show the recognised type (m4a) ? Have you tried checking your files' metadata with something like mediainfo ?

[MadMax]

What about the timestamp? Do the "changed" files have a newer timestamp than the others? Maybe you can trace the change back to a certain event? Like opening them with a program that converts them or something? I had an issue with nomacs silently editing (rotated) pictures (but not changing the file type), but I have not encountered a similar thing with audio or video files. Converting mp3 to m4a also would need some cpu power and probably not go unnoticed.

Like other stated, maybe they were m4a all along and the extension was just mp3?
You can also check the actual filetype via hex editor or with hexdump -C. mp3 files begin with "ID3" while m4a should begin with "ftypM4A".

[baldyeti]

You can also simply use the "file" command for basic identification:

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$ file 2022-08-04-20:37:41.mp3
2022-08-04-20:37:41.mp3: MPEG ADTS, layer III, v1, 256 kbps, 44.1 kHz, JntStereo
$ file 2022-08-04-20:35:58.m4a
2022-08-04-20:35:58.m4a: ISO Media, MP4 v2 [ISO 14496-14]

[Stevo]

m4a uses aac encoding instead of mpeg layer 3 (mp3), so it's not just a renaming--the computer has to do some heavy work to transcode those.

Unless it really did use magic, in which case you should research if it can get around the heavy computation required for cryptocurrency mining, and become very rich very quick.