<p>If you run <code>ffmpeg -layouts</code>, you will see that stereo indicates the presence of two channels, one assigned as Front Left and the other as Front Right. If you use <code>-ac 2</code> in your encode, ffmpeg will create a stereo layout output by default. FFmpeg does not display the individual channel assignments in the readout of the file.</p>

CC BY-SA 3.0
2016-12-12T19:52:32.473Z
2016-12-12T19:52:32.473Z
Gyan
<p>I have an unusual problem that I hope someone can help me solve.
I have 45 video files that I'm batch encoding as MP4.
Some of those files have their audio channel position set to Front L R and others have have it set to Front C.
However, the distribution system which these videos are sent to (and which I have no control over) does some re-processing of these videos.
All the videos that have their Channel Position set to Front C are coming back with distorted audio. </p>

<p>My question is:</p>

<p>Does anyone know how to encode a video with ffmpeg and force the audio channel positions to be Front L R?
(I have carefully studied this page (<a href="https://trac.ffmpeg.org/wiki/AudioChannelManipulation#monostereo" rel="nofollow noreferrer">https://trac.ffmpeg.org/wiki/AudioChannelManipulation#monostereo</a>) but it was not obvious what the solution might be)</p>

<p>Thank you!</p>

CC BY-SA 3.0
2016-12-12T18:54:18.533Z
The encoder will set stereo layout when you encode with `-ac 2` as shown in the wiki you linked to.
Gyan
CC BY-SA 3.0
2016-12-12T19:40:32.303Z
@Mulvya Thank you, I tried your suggestion. After encoding ffmpeg reported the following for the audio information: "Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)" It's not clear to me how to read this. Does LC mean "Left Channel"?
d13
CC BY-SA 3.0
2016-12-12T19:49:28.013Z
No. LC means Low Complexity and refers to the audio bitstream profile.
Gyan
<ffmpeg><audio><encoding>
Mono to Stereo using FFMPEG
d13
# Mono to Stereo using FFMPEG

(Asked by: username_0 on 2016-12-12)

I have an unusual problem that I hope someone can help me solve.
I have 45 video files that I'm batch encoding as MP4.
Some of those files have their audio channel position set to Front L R and others have have it set to Front C.
However, the distribution system which these videos are sent to (and which I have no control over) does some re-processing of these videos.
All the videos that have their Channel Position set to Front C are coming back with distorted audio.

My question is:

Does anyone know how to encode a video with ffmpeg and force the audio channel positions to be Front L R?
(I have carefully studied this page (<https://trac.ffmpeg.org/wiki/AudioChannelManipulation#monostereo>) but it was not obvious what the solution might be)

Thank you!

**Tags:** ffmpeg, audio, encoding

> **Comments:**
> **username_1**: The encoder will set stereo layout when you encode with `-ac 2` as shown in the wiki you linked to.  
> **username_0**: @Mulvya Thank you, I tried your suggestion. After encoding ffmpeg reported the following for the audio information: "Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)" It's not clear to me how to read this. Does LC mean "Left Channel"?  
> **username_1**: No. LC means Low Complexity and refers to the audio bitstream profile.  

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## 1 answers

### Answer by username_1 on 2016-12-12. Score: 7 | Accepted answer

If you run `ffmpeg -layouts`, you will see that stereo indicates the presence of two channels, one assigned as Front Left and the other as Front Right. If you use `-ac 2` in your encode, ffmpeg will create a stereo layout output by default. FFmpeg does not display the individual channel assignments in the readout of the file.


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