I have created a PHP code which compresses mp3 while uploaded to 32kbps bit rate I have referred this thread

How to compress or convert to low quality Mp3 file from PHP

used this code

exec("ffmpeg -i inputfile.mp3 -ab 24000 outputfile.mp3")

but the problem is I can't compress more than 32kbps .my code instruct to compress up to 24kbps but after execution, I can see the output file is 32kbps. can anyone tell what should I do so that I can compress more than 32kbps .or is there any limitation of ffmpeg ??

php ffmpeg
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