Low Bitrate When Exporting FLACs to AACs

Let me begin by stating I am extremely new to all of this digital recording, and the exporting of files. I have been gifted about 3TB worth of FLACs that I was to use to DJ. I did not know how FLACs differed from MP3s, but when I saw the size of the files and the bitrates I began to understand. I then determined I wanted to keep the FLACs, but also create smaller files around the 320 kbps range. I installed the ffmpeg-mac-2.2.2pkg and began exporting, but afterward all of the files have a bitrate around 192kbps. I am choosing the highest setting for sound quality (500), and I still only get 192kbps. What am I doing wrong?

I’m not a Mac user so I can’t help with the nitty-gritty details…

A FLAC (made from a CD*) is usually around 700kbps so your 320kbps files will be about half the size. At 500kbps you wouldn’t be saving much space at all. Is it worth it?

And I suspect you’re making AAC files, not MP3. AAC is supposed to be “better” than MP3. That is it may give you better quality and/or smaller files. But in many cases, the MP3 and AAC will both sound identical to the lossless original (in a blind ABX test).

FFmpeg can make MP3s but usually we use LAME for MP3s. And, the maximum MP3 bitrate is 320kbps so you can’t go to 500kbps.

The 192kbps AAC limit is (was?) a “known bug” and I believe the work-around is to convert to AAC with iTunes (or some other tool). But, I don’t think iTunes can read FLAC, so you might have to convert to WAV first if you want to use iTunes.

Or, 192kbps is probably good enough. You can A/B them (some of them) with your FLACS and if you think you’re hearing a difference (it’s easy to fool yourself) you might want to try a [u]blind ABX test[/u].

And even if you can hear a difference with careful listening the differences should be small at 192kbps, and probably impossible to hear in a DJ situation". And there is no “A” to compare with, and if you have an awesome sounding DJ/PA system it should sound awesome.

Speaking of different formats, Apple’s version of lossless compression is ALAC (similar to FLAC).


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  • More than 16-bits, or a sample rate higher than 44.1kHz, or more channels will give you a higher bitrate and a bigger FLAC.