How to encode an existing audio track to aac #
#!/bin/sh
mkfifo temp.wav
screen -d -m mplayer "$1" -vc null -vo null -ao pcm:fast:waveheader:file=temp.wav
./neroAacEnc -ignorelength -q 0.30 -if temp.wav -of "$1.aac"
rm temp.wav
I use screen but you can also use & or two terminals.
Sometimes mplayer is too worried about seeks and don’t work so you can use ffmpeg instead :
#!/bin/sh
mkfifo temp.wav
screen -d -m ffmpeg -i "$1" -y -acodec pcm_s16le -f wav -ar 48000 temp.wav
./neroAacEnc -ignorelength -q 0.30 -if temp.wav -of "$1.aac"
rm temp.wav
Beware the -y is very important to allow ffmpeg to overwrite the fifo file.