c - How to decode mp3 to pcm by ffmpeg - Stack Overflow
FFmpeg - Wikipedia
How to Convert WebM to MP3 with FFmpeg Easily
How to Fix Audacity AAC Import and Export Failure Issue?
AAC to MP3 Android: How to Convert AAC to MP3 on Android
Audacity tutorial: Converting to mp3 or AAC and other formats, example: Matthew Smith - epic orchestral synth music for film and game effects; Buanzo's LAME mp3 library