I’m trying to convert a WAV file (decoded from FLAC) to MP3 CBR @ 320 and so far, ffmpeg has been doing all I need. However, I can see a very consistent difference between LAME CLI, ffmpeg and Audacity with LAME when comparing with a few tools:
Tools
- LAME 3.100 CLI
- ffmpeg 4.2 (Lavf 58.29.100/LAME 3.100) CLI
- Audacity 2.3.2 (LAME 3.100)
RESULTS
MediaInfo
- LAME: Constant/320/Encoder Settings: -m s -V 4 -q 3 -lowpass 20.5
- ffmpeg: Variable/320/
- Audacity: Constant/320/Encoder Settings: -m s -V 4 -q 3 -lowpass 20.5
Spectral Analysis
- LAME: Almost nothing between shelf and cutoff
- ffmpeg: Almost nothing between shelf and cutoff
- Audacity: Considerably more happening between shelf and cutoff
Fakin’ the Funk*
- LAME: 256kbps
- ffmpeg: 192kbps
- Audacity: 320kbps
*I know that this tool is not a really good indicative and is probably misreading info, but it seems to a least notice the visible difference the Audacity file has in it’s spectrogram
Commands/settings used for the encodes:
LAME: lame -b 320 -q 3 -m s .wav .mp3
ffmpeg: ffmpeg -i “.wav” -c:a libmp3lame -b:a 320k -compression_level 2 -cutoff 20500 -joint_stereo 0 “.mp3” -y
Audacity: Import .wav file > Export as MP3 > Insane preset, Stereo, Default Variable Speed
What I’d like to understand is why all of this results are coming different, if they are all, in theory, LAME and why Audacity produces such a different spectrogram that I can easily point out between the 3, but can’t tell what are the other 2. Whatever settings it’s using with LAME, I want to replicate that.
Thanks