Need help - error converting to MP3 with LAME


We recently upgraded to Asterisk

We need the calls recorded with Monitor command in MP3 format. The wav files generated by asterisk after combining the in and out files were converted to MP3 using LAME. It used to work fine earlier. But after the recent upgrade, I get this error:

Warning: corrupt or unsupported WAVE format
Assuming raw pcm input file

I noticed the bit rate of the wav files is different (was 128kbps, now 13kbps). But not sure yet if that’s the cause of the problem or not and what to do to resolve this.

I would really appreciate if you could provide any help.