What is the right command to convert an mp3 file to the required codec version (MPEG version 2) and bit rate (48 kbps) for Amazon Alexa SSML?

Question

I am trying to convert an mp3 file to the format expected by the audio tag in the Amazon Alexa SSML markup language as described here: https://developer.amazon.com/public/soluti

Answer 1

Here's what I had to do to get it working:

ffmpeg -i input.mp3 -b:a 48k -ar 16000 output.mp3

Here's the output when I play it with mpg123:

$ mpg123 output.mp3 
High Performance MPEG 1.0/2.0/2.5 Audio Player for Layers 1, 2 and 3
        version 1.22.4; written and copyright by Michael Hipp and others
        free software (LGPL) without any warranty but with best wishes

Playing MPEG stream 1 of 1: output.mp3 ...

MPEG 2.0 layer III, VBR, 16000 Hz joint-stereo

[0:02] Decoding of output.mp3 finished.