Convert mp3 from mono to stereo using Lame

Question

An application requires that the mp3 files it receives are encoded with 2 channels (stereo), but the original files have only 1 channel (mono).
We use Lame for conversion, but i fail to make it clone the mono channel and create a fake stereo.

lame.exe -m j mono.mp3 stereo.mp3

-m d or -m s doesn't seem to work either. Is it possible to do this with lame?

score 5 · Accepted Answer · answered Sep 12 '12 at 10:05

The answer to my own question is: No - it is not possible with lame

My work-around solution is to use the command-line tool sox and do the channel duplication prior to mp3-conversion:

sox mono.wav -c 2 stereo.wav

Then afterwards use lame:

lame -m j stereo.wav stereo.mp3

score 2 · Answer 2 · answered May 31 '16 at 18:51

2

You can do that with ffmpeg. Here is the command I used for mono mp3 files with 11025 Hz sampling rate and 40 kbps bitrate:

ffmpeg -i mono.mp3 -ac 2 -ab 96000 -ar 22050 stereo.mp3

answered May 31 '16 at 18:51

Dzmitry

141

abekonge · Answer 3 · 2018-04-10T06:59:18.990

1

You can use lame for this. With mono wav input, just use -m s as lame option. Using otherwise default lame options the output will be (simple) stereo.

EDIT: I was wrong! The original posters answer was correct: When the input wav is mono, you cannot get lame to make it stereo with -m s.

edited Apr 10 '18 at 06:59

answered Apr 09 '18 at 06:58

abekonge

11

score 0 · Answer 4 · answered Sep 06 '12 at 08:50

0

According to the LAME Documentation @Modes I would try "-m d". You should also consider to double your bitrate, because it is shared by two channels now, not one.

answered Sep 06 '12 at 08:50

Chake

161

Convert mp3 from mono to stereo using Lame

4 Answers4

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