I'm trying encoding some of my audio files into low bitrate (24kpbs) streams.
Suprisingly, encoding one audio file (wmav2 format) containing conversation produces an almost silent audio file with noises. I've tried neroaacenc, winamppro on Windows and ffmpeg with libaacplus, ffmpeg with libfdk_aac, Max and XLD on Mac.
Command line I used is as follows:
ffmpeg -i <input_file> -vn -sn -c:a libfdk_aac -profile:a aac_he_v2 -ar:a 44100 -ac:a 2 -b:a 24k -f adts <output_file>
ffmpeg -i <input_file> -vn -sn -c:a libaacplus -ar:a 44100 -ac:a 2 -b:a 24k -f adts <output_file>
Please check out the <input_file> in attachment