How to change mp3 bitrate ? (Delphi)

Question

how can i change the constant bitrate(CBR) of mp3 files ? (such as 64kbps - 128kbps - 192kbps)

Answer 1

You need to re-encode the mp3. Since I know of no good mp3 codec written in Delphi you'll need a wrapper around a c library such as lame.

If you have access to the original audio-data (Wave, FLAC,...) then you better encode from the lossless to the new bit-rate since chaining lossy encodes reduces the quality.

You might also need to look into the mp3 licensing terms. Some kinds of usage are free, but you need to pay for others.

Answer 2

BASS is a good library for sound handling.
It includes wrappers for Delphi.
Reencoding involves decoding the MP3 files, then encode in a different bitrate.
BASS can natively decode MP3 files and streams.
BASS has encoder-wrappers for various encodings (using external encoders) for instance using LAME for MP3 encoding (the easiest is to pick download a precompiled Lame Bundle).

BASS licensing is free for non-commercial use.
They have a great forum for support.

--jeroen