<h2>How to concatenate two MP4 files using FFmpeg?</h2>
<p>Step 1. Ensure you have FFmpeg installed.</p>
<ul>
<li>If you're on Windows, you can download FFmpeg from the official website: <a href="https://ffmpeg.org/download.html">https://ffmpeg.org/download.html</a></li>
<li>If you're on macOS, you can install FFmpeg using Homebrew:
<pre>
brew install ffmpeg
</pre>
</li>
<li>If you're on Linux, you can install FFmpeg using your package manager, e.g.,
<pre>
sudo apt-get install ffmpeg
</pre>
</li>
</ul>
<p>Step 2. Prepare your MP4 files.</p>
<p>Make sure that the MP4 files you want to concatenate have the same video codec, resolution, and frame rate. If not, you can use FFmpeg to convert them to a common format using the following command:</p>
<pre>
ffmpeg -i input1.mp4 -c:v libx264 -crf 23 -c:a aac -b:a 160k output1.mp4
ffmpeg -i input2.mp4 -c:v libx264 -crf 23 -c:a aac -b:a 160k output2.mp4
</pre>
<p>Step 3. Create a text file containing the list of MP4 files.</p>
<p>Using a text editor, create a new file named "input.txt" and add the following lines to it:</p>
<pre>
file 'path/to/output1.mp4'
file 'path/to/output2.mp4'
</pre>
<p>Be sure to replace the paths with the actual paths to your MP4 files.</p>
<p>Step 4. Concatenate the MP4 files.</p>
<p>Open a command prompt or terminal window and navigate to the directory where your MP4 files and the input.txt file are located. Then, run the following command:</p>
<pre>
ffmpeg -f concat -safe 0 -i input.txt -c copy output.mp4
</pre>
<p>This will concatenate the MP4 files listed in input.txt into a single file named output.mp4.</p>
<p>Step 5. Verify that the concatenation was successful.</p>
<p>Use a video player to open the output.mp4 file and verify that it plays smoothly. If there are any problems, you can try using a different video codec or increasing the bitrate.</p>