Answers.Body: <p>The concat demuxer expects a text file as input.</p>
  
  <pre><code>ffmpeg -f concat -safe 0 -i list.txt -c copy concat.avi
  </code></pre>
  
  <p>where list.txt is</p>
  
  <pre><code>file 'intro_prepped.avi'
  file 'intro_prepped.avi'
  </code></pre>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-06-20T03:40:41.173Z
Answers.LastActivityDate: 2017-06-20T03:40:41.173Z
Answers.UserDisplayName: Gyan
Body: <p>I am trying to concatenate two video files using ffmpeg, and am receiving and error.</p>
  
  <p>Two eliminate compatibility issues between the two videos, I am been concatenating the same video with itself, and the same error persists.</p>
  
  <pre><code>ffmpeg -f concat -safe 0 -i intro_prepped.avi intro_prepped.avi -c copy concat.avi  
  </code></pre>
  
  <p>And the error output I receive is....</p>
  
  <blockquote>
    <p>[concat @ 0x220d420] Line 1: unknown keyword 'RIFFf�?'
    intro_prepped.avi: Invalid data found when processing input</p>
  </blockquote>
  
  <p>I have tried various combinations of concat flags and have not been able to get it to work. Has anyone seen this error before?</p>
  
Tags: <ffmpeg><command-line>
Title: ffmpeg concat error
UserDisplayName: Scorb
ThreadText: # ffmpeg concat error
  
  (Asked by: username_0 on 2017-06-20)
  
  I am trying to concatenate two video files using ffmpeg, and am receiving and error.
  
  Two eliminate compatibility issues between the two videos, I am been concatenating the same video with itself, and the same error persists.
  
  ```
  ffmpeg -f concat -safe 0 -i intro_prepped.avi intro_prepped.avi -c copy concat.avi  
  
  ```
  
  And the error output I receive is....
  
  > [concat @ 0x220d420] Line 1: unknown keyword 'RIFFf�?'
  > intro\_prepped.avi: Invalid data found when processing input
  
  I have tried various combinations of concat flags and have not been able to get it to work. Has anyone seen this error before?
  
  **Tags:** ffmpeg, command-line
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2017-06-20. Score: 6 | Accepted answer
  
  The concat demuxer expects a text file as input.
  
  ```
  ffmpeg -f concat -safe 0 -i list.txt -c copy concat.avi
  
  ```
  
  where list.txt is
  
  ```
  file 'intro_prepped.avi'
  file 'intro_prepped.avi'
  
  ```
  
  
  ---
  
  