What command should I use to convert a
mp3 file to
wav whose bitrate is variable. Or better how would I know whether that source audio is
fixed bitrate or
You can get some info about the bitrate of your input files by using the
When you use lossy output codecs (such as MPEG-1 Layer III or AAC), ffmpeg chooses a default bitrate for the output stream, or a variable bitrate. It depends on the encoder itself.
For lossless codecs, you cannot set a bitrate, since each sample will take a predefined number of bits.
If you want a smaller file size for the PCM-encoded WAV file, set a sample format with less bit depth (see
Here's an example of doing both: