How do I produce great quality AAC files under Xenial Xerus?
I would like to produce high quality AAC files from a small library of wav files under Xenial Xerus 16.04 LTS.
I am keen to be able to select between AAC-LC, HE-AAC and HE-AAC v2 for the output files. I am not all that fussed if either a commandline or gui tool does a better job...
Under Xenial Xerus the best choice is to use fdkaac:
sudo apt-get install fdkaac
Then the following syntax should be helpful, all examples are for Constant Bitrate Mode (CBR) although I have included a section at the bottom concerning Variable Bitrate Mode (VBR):
1. AAC-LC
For a single file try this:
fdkaac --bitrate 128k --moov-before-mdat --afterburner 1 -o output.m4a input.wav
and for a directory of wav files try the following:
mkdir aac && \
for j in *.wav
do
fdkaac --bitrate 128k --moov-before-mdat --afterburner 1 -o aac/"${j%.wav}.m4a" "$j"
done
Tested and working well on my system.
2. HE-AAC
For a single file try this:
fdkaac -p 5 --bitrate 64k --moov-before-mdat --afterburner 1 -o output.m4a input.wav
and for a directory of wav files try the following:
mkdir aac && \
for j in *.wav
do
fdkaac -p 5 --bitrate 64k --moov-before-mdat --afterburner 1 -o aac/"${j%.wav}.m4a" "$j"
done
Tested and working well on my system.
3. AAC-HEv2
For a single file try this:
fdkaac -p 29 --bitrate 32k --moov-before-mdat --afterburner 1 -o output.m4a input.wav
and for a directory of wav files try the following:
mkdir aac && \
for j in *.wav
do
fdkaac -p 29 --bitrate 32k --moov-before-mdat --afterburner 1 -o aac/"${j%.wav}.m4a" "$j"
done
Tested and working well on my system.
4. VBR Note:
If you wish to use Variable Bitrate (VBR) mode instead of Constant Bitrate (CBR) simply omit the --bitrate
setting and use --bitrate-mode
instead. bitrate-mode
takes a setting from 1 to 5 with a higher value producing a higher bitrate.
Further Reading:
- Hydrogen Audio: Fraunhofer FDK AAC
- abcde: Encoding with fdkaac
- GitHub: fdkaac