<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>

CC BY-SA 3.0
2017-06-20T03:40:41.173Z
2017-06-20T03:40:41.173Z
Gyan
<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>

<ffmpeg><command-line>
ffmpeg concat error
Scorb
# 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


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## 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'


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