Answers.Body: <pre><code>ffmpeg -f concat -i playlist.txt $OTHER_OPTIONS
  </code></pre>
  <p>In playlist.txt, write this:</p>
  <pre><code>file 'B'
  file 'A'
  inpoint &lt;start_of_extra_content&gt;
  </code></pre>
  <p>Would you like to know <a href="https://ffmpeg.org/ffmpeg-formats.html#concat-1" rel="nofollow noreferrer">more</a>?</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-08-04T18:32:46.663Z
Answers.LastActivityDate: 2021-08-04T18:32:46.663Z
Answers.UserDisplayName: stribika
Answers.Body: <p>Assuming the duration of B is X (in seconds), you would use</p>
  
  <pre><code>ffmpeg -i A -i B -filter_complex "[0]volume=0:enable='lt(t,X)'[a];[a][1]amix=duration=first:dropout_transition=0,volume=2" out
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-03-18T06:49:14.540Z
Answers.LastActivityDate: 2019-03-18T06:49:14.540Z
Answers.UserDisplayName: Gyan
Body: <p>With audio files A and B:</p>
  
  <p>A : <code>|--- Some content ---|--- Extra content --- |</code></p>
  
  <p>B : <code>|--- Some content ---|</code></p>
  
  <p>Assume the end of B is where the start of the extra content in A.</p>
  
  <p>I want to append that extra content at the end of B.</p>
  
  <p>Can I achieve this with some command line programs, such as ffmpeg?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-03-18T05:40:27.743Z
Comments.Text: Do you know the duration of B? Do the files have the same format/codec properties?
Comments.UserDisplayName: Gyan
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-03-18T06:28:45.513Z
Comments.Text: I think I could get the duration of B with some methods. A and B may or maybe in different codecs.
Comments.UserDisplayName: kit
Tags: <ffmpeg><audio>
Title: Append part of the audio at the end of another audio
UserDisplayName: kit
ThreadText: # Append part of the audio at the end of another audio
  
  (Asked by: username_0 on 2019-03-16)
  
  With audio files A and B:
  
  A : `|--- Some content ---|--- Extra content --- |`
  
  B : `|--- Some content ---|`
  
  Assume the end of B is where the start of the extra content in A.
  
  I want to append that extra content at the end of B.
  
  Can I achieve this with some command line programs, such as ffmpeg?
  
  **Tags:** ffmpeg, audio
  
  > **Comments:**
  > **username_1**: Do you know the duration of B? Do the files have the same format/codec properties?  
  > **username_0**: I think I could get the duration of B with some methods. A and B may or maybe in different codecs.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2021-08-04. Score: 0
  
  ```
  ffmpeg -f concat -i playlist.txt $OTHER_OPTIONS
  
  ```
  
  In playlist.txt, write this:
  
  ```
  file 'B'
  file 'A'
  inpoint <start_of_extra_content>
  
  ```
  
  Would you like to know [more](https://ffmpeg.org/ffmpeg-formats.html#concat-1)?
  
  
  ---
  
  ### Answer by username_1 on 2019-03-18. Score: 0
  
  Assuming the duration of B is X (in seconds), you would use
  
  ```
  ffmpeg -i A -i B -filter_complex "[0]volume=0:enable='lt(t,X)'[a];[a][1]amix=duration=first:dropout_transition=0,volume=2" out
  
  ```
  
  
  ---
  
  