Answers.Body: <p>Just <code>-c</code> on its own will set the encoder for all types of streams: video, audio..etc. libopus can't encode video, obviously. You need to attach a stream specifier to limit it to audio, so</p>
  
  <pre><code>ffmpeg -i abc.mkv -map 0:v -c copy -map 0:a -c:a libopus -b:a 128k xyz.mkv
  </code></pre>
  
  <p>See the section on <a href="https://ffmpeg.org/ffmpeg.html#Stream-specifiers-1" rel="nofollow noreferrer">stream specifiers</a> and also this <a href="https://superuser.com/a/1219824/114058">answer</a> on how multiple codec settings in a command works.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-12-23T16:26:50.663Z
Answers.LastActivityDate: 2018-12-23T16:26:50.663Z
Answers.UserDisplayName: Gyan
Body: <p>I'm totally new to ffmpeg and use it on windows.
  I want to encode the audio from a mkv video to opus, using</p>
  
  <pre><code>ffmpeg -i abc.mkv -map 0:v -c copy -map 0:a -c libopus -b:a 128000 xyz.mkv
  </code></pre>
  
  <p>but I get the error:</p>
  
  <pre><code>invalid encoder type "libopus". 
  </code></pre>
  
  <p>What am I doing wrong?</p>
  
Tags: <ffmpeg>
Title: convert audio to libopus with ffmpeg
UserDisplayName: Mike8725
ThreadText: # convert audio to libopus with ffmpeg
  
  (Asked by: username_0 on 2018-12-23)
  
  I'm totally new to ffmpeg and use it on windows.
  I want to encode the audio from a mkv video to opus, using
  
  ```
  ffmpeg -i abc.mkv -map 0:v -c copy -map 0:a -c libopus -b:a 128000 xyz.mkv
  
  ```
  
  but I get the error:
  
  ```
  invalid encoder type "libopus". 
  
  ```
  
  What am I doing wrong?
  
  **Tags:** ffmpeg
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2018-12-23. Score: 1 | Accepted answer
  
  Just `-c` on its own will set the encoder for all types of streams: video, audio..etc. libopus can't encode video, obviously. You need to attach a stream specifier to limit it to audio, so
  
  ```
  ffmpeg -i abc.mkv -map 0:v -c copy -map 0:a -c:a libopus -b:a 128k xyz.mkv
  
  ```
  
  See the section on [stream specifiers](https://ffmpeg.org/ffmpeg.html#Stream-specifiers-1) and also this [answer](https://superuser.com/a/1219824/114058) on how multiple codec settings in a command works.
  
  
  ---
  
  