<p><code>-ac 2</code> will work for any number of input channels. The example is just one use-case.</p>

CC BY-SA 4.0
2023-12-06T03:57:37.683Z
2023-12-06T03:57:37.683Z
The Somberi
<p>I have a file with 7.1 audio, where each channel is in a separate mono stream. How can I convert all these mono streams to plain stereo?</p>
<p>(The <a href="https://trac.ffmpeg.org/wiki/AudioChannelManipulation#a5.1stereo" rel="nofollow noreferrer">documentation</a> suggests to use the <code>-ac 2</code> option, but that is meant for converting 5.1 in one stream of 6 channels, not 8 separate streams)</p>
<p>The audio I have has the streams labelled, presumably correctly, so that might help:</p>
<pre class="lang-sh prettyprint-override"><code>$ mediainfo &quot;$in&quot; | egrep '^(Audio|Channel)'
Audio #1
Channel(s)                               : 1 channel
Channel layout                           : Lt
Audio #2
Channel(s)                               : 1 channel
Channel layout                           : Rt
Audio #3
Channel(s)                               : 1 channel
Channel layout                           : L
Audio #4
Channel(s)                               : 1 channel
Channel layout                           : R
Audio #5
Channel(s)                               : 1 channel
Channel layout                           : C
Audio #6
Channel(s)                               : 1 channel
Channel layout                           : LFE
Audio #7
Channel(s)                               : 1 channel
Channel layout                           : Ls
Audio #8
Channel(s)                               : 1 channel
Channel layout                           : Rs
</code></pre>
<p><strong>Update</strong>:
In fact, the file I have is not 7.1, but Stereo + 5.1. So I already have the stereo tracks that I want, correctly labelled &quot;Lt&quot; and &quot;Rt&quot;.</p>
<p>But there is still an aspect in the question which I would like to learn: how to convert 7.1 or 5.1 separate mono streams to a single stereo stream?</p>

<ffmpeg><audio><stereo>
ffmpeg from 5.1 or 7.1 audio in separate mono streams to stereo
mivk
# ffmpeg from 5.1 or 7.1 audio in separate mono streams to stereo

(Asked by: username_0 on 2023-11-17)

I have a file with 7.1 audio, where each channel is in a separate mono stream. How can I convert all these mono streams to plain stereo?
(The documentation suggests to use the -ac 2 option, but that is meant for converting 5.1 in one stream of 6 channels, not 8 separate streams)
The audio I have has the streams labelled, presumably correctly, so that might help:
$ mediainfo "$in" | egrep '^(Audio|Channel)'
Audio #1
Channel(s)                               : 1 channel
Channel layout                           : Lt
Audio #2
Channel(s)                               : 1 channel
Channel layout                           : Rt
Audio #3
Channel(s)                               : 1 channel
Channel layout                           : L
Audio #4
Channel(s)                               : 1 channel
Channel layout                           : R
Audio #5
Channel(s)                               : 1 channel
Channel layout                           : C
Audio #6
Channel(s)                               : 1 channel
Channel layout                           : LFE
Audio #7
Channel(s)                               : 1 channel
Channel layout                           : Ls
Audio #8
Channel(s)                               : 1 channel
Channel layout                           : Rs

Update:
In fact, the file I have is not 7.1, but Stereo + 5.1. So I already have the stereo tracks that I want, correctly labelled "Lt" and "Rt".
But there is still an aspect in the question which I would like to learn: how to convert 7.1 or 5.1 separate mono streams to a single stereo stream?

**Tags:** ffmpeg, audio, stereo


---

## 1 answers

### Answer by username_1 on 2023-12-06. Score: 0

`-ac 2` will work for any number of input channels. The example is just one use-case.


---

