Trying to convert my old Flac collection into a lossy format.

[Man]

Hi,

This is my very first post here hence I'm not sure if I'm allowed to ask this or not but... I'm trying to convert my old lossless collection into a lossy format to save space on my phone's memory card. I normally wouldn't have done this but I don't have good earphones anymore + my hearing isn't as good as it used to be as there's permeant ringing (tinnitus) in my left ear thanks to a trauma so... I'm sure you can understand my little predicament!

 

In any case, I've converted some samples via Audacity and the results are rather strange. It seems like its 220-260Kbps "variable" mode is not only making slightly lighter MP3s (3x less compared to master quality) but also preserving more details than the 320Kbps "insane" preset + it seems like AAC is discarding a lot of data without any significant reduction in file size?

 

Which compression should I chose? I'm leaning towards the variable MP3 as 320K's slightly extra detail in the 15-20KHz range is pretty much unnoticeable to me and the AAC compression simply doesn't make any sense even though its slightly closer to the master file in 10-15kHz range than MP3s, as far as I can tell at least: 

 

Master file (FLAC) @ 32.4MB:

 

320Kbps MP3 (Insane) @ 11.2MB:

 

~224Kbps MP3 (Variable) @ 9.6MB: 

 

320Kbps AAC @ 10.9MB: 

[Roswell]

That looks like a bad encode with AAC. AAC @ 256Kbit VBR is going to be much better (and smaller in size) than MP3 @ 320Kbit. 

 

A comparison should look something like this:

 

[Kilrah]

Looks like an encoder bug...

[Man]

@Roswell It is just me or is your 278Kbps AAC encoding actually ~90% identical to 1Mbps lossless? That's some serious digital voodoo! I was originally leaning towards AACs myself as I've heard nothing but great things about the compression but the end result was extremely underwhelming via Audacity so I started experimenting with MP3s instead.

 

There's definitely an AAC encoder bug or something in Audacity, as confirmed by @Kilrah. Anyhow, can you tell me about the software you used to convert that ALAC to AAC?

[Man]

Update:

 

Just tried LameXP's AAC encoder (comes with a ton of tweaks, surprisingly, given its age) and the result is MUCH superior than Audacity's "insane" 320Kbps MP3 preset and nearly indistinguishable (~90%) with the master file as you can see below.

 

At a glance; MP3 cuts off to at about 19-20kHz, which I think is its inherit limitation, but AAC goes all the way up to 22kHz like FLACs with minimal data loss and I'm more than happy with the result.

 

As a side note; I've had the pleasure of listening to some premium cassette decks back in the days and I genuinely think that a 320K AAC file can trade blows with premium metal tapes, as long as it's properly encoded. 

 

In any case, consider this thread as solved, unless you're aware of a better AAC encoding software in which case do let me know!

 

Thanks.