<p>I think the simplest way to this is to use MP4Box.</p>

<pre><code>./MP4Box -add file1.mp4 -cat file2.mp4 -cat file3.mp4 output.mp4
</code></pre>

CC BY-SA 3.0
2012-12-24T23:47:16.437Z
2012-12-24T23:47:16.437Z
paulgrav
<p>I was encountering audio sync issues when trying to do this with Avidemux, but I came upon a two-step process that keeps the audio in sync:</p>

<ol>
<li>Concatenate files using <a href="https://www.bunkus.org/videotools/mkvtoolnix/downloads.html" rel="nofollow">MKVToolNix</a> (I used version 7.4.0 for Mac). This results in a Matroska video (.mkv) file.</li>
<li>Remux the .mkv file to MP4 format using <a href="http://fixounet.free.fr/avidemux/download.html" rel="nofollow">Avidemux</a> (I used verison 2.6 for Mac). I chose the MP4v2muxer option in the Output Format section. This results in an MP4 file with audio and video in sync.</li>
</ol>

CC BY-SA 3.0
2015-01-02T01:43:11.363Z
2015-01-02T01:43:11.363Z
Sasha Vodnik
<p>I would suggest using ffmpeg, and the <code>-vcopy</code> switch.  <em>Usually</em> this will work, but it depends on codec support.  </p>

<p>Various builds of it have various codecs.  If one version of it doesn't work, try downloading a copy from a different site.</p>

CC BY-SA 3.0
2012-04-13T17:11:30.560Z
2012-04-13T17:11:30.560Z
Brad
<p>i think <a href="http://www.squared5.com/" rel="nofollow">MPEG Streamclip</a> can do this.  It's free on mac and pc.</p>

CC BY-SA 3.0
2015-01-02T11:34:57.613Z
2015-01-02T11:34:57.613Z
tomh
<p><a href="http://fixounet.free.fr/avidemux/" rel="nofollow">Avidemux</a> should do the work. </p>

<ol>
<li>Load File </li>
<li>Go to File -> Append and select File </li>
<li>To the left of the video window, 
<ul>
<li>set video mode to Copy; </li>
<li>same for audio mode; </li>
<li>set format to MP4. </li>
</ul></li>
<li>Go to File -> Save -> Video.</li>
</ol>

CC BY-SA 3.0
2012-04-03T17:43:12.983Z
This does what I am looking for, but it is causing the audio to go out of sync at the join point. I am going to try and join and mix the audio from a separate channel.
Jim McKeeth
CC BY-SA 3.0
2012-04-03T05:11:07.103Z
2012-04-04T02:14:18.320Z
2012-04-04T02:14:18.320Z
Gyan
<p>I have two MP4 files that I generated with <a href="http://www.techsmith.com/camtasia.html" rel="nofollow">Camtasia Studio</a>. I need to join them together post rendering with Camtasia (it can't be done during the Camtasia rendering process). Looking for a utility or technique that will work to join these, preferably that doesn't require re-rendering all the video again.</p>

<p><strong>Update</strong>: Either Windows (preferred) or Mac. Doesn't need a GUI if it is a good command-line app.</p>

CC BY-SA 3.0
2012-04-02T23:21:11.857Z
It would help to know what platform/OS you are using.
filzilla
CC BY-SA 3.0
2012-04-03T17:44:54.887Z
@filzilla: Either Windows (preferred) or Mac.
Jim McKeeth
CC BY-SA 3.0
2012-04-12T10:50:20.257Z
See http://superuser.com/q/51047/31983
200_success
<file-formats><mac><windows><mp4>
Utility or method for joining MP4 files
Jim McKeeth
# Utility or method for joining MP4 files

(Asked by: username_0 on 2012-04-02)

I have two MP4 files that I generated with [Camtasia Studio](http://www.techsmith.com/camtasia.html). I need to join them together post rendering with Camtasia (it can't be done during the Camtasia rendering process). Looking for a utility or technique that will work to join these, preferably that doesn't require re-rendering all the video again.

**Update**: Either Windows (preferred) or Mac. Doesn't need a GUI if it is a good command-line app.

**Tags:** file-formats, mac, windows, mp4

> **Comments:**
> **username_1**: It would help to know what platform/OS you are using.  
> **username_0**: @username_1: Either Windows (preferred) or Mac.  
> **username_2**: See http://superuser.com/q/51047/31983  

---

## 5 answers

### Answer by username_3 on 2012-12-24. Score: 4

I think the simplest way to this is to use MP4Box.
./MP4Box -add file1.mp4 -cat file2.mp4 -cat file3.mp4 output.mp4


---

### Answer by username_4 on 2015-01-02. Score: 2

I was encountering audio sync issues when trying to do this with Avidemux, but I came upon a two-step process that keeps the audio in sync:

1. Concatenate files using [MKVToolNix](https://www.bunkus.org/videotools/mkvtoolnix/downloads.html) (I used version 7.4.0 for Mac). This results in a Matroska video (.mkv) file.
2. Remux the .mkv file to MP4 format using [Avidemux](http://fixounet.free.fr/avidemux/download.html) (I used verison 2.6 for Mac). I chose the MP4v2muxer option in the Output Format section. This results in an MP4 file with audio and video in sync.


---

### Answer by username_5 on 2012-04-13. Score: 1

I would suggest using ffmpeg, and the `-vcopy` switch. *Usually* this will work, but it depends on codec support.

Various builds of it have various codecs. If one version of it doesn't work, try downloading a copy from a different site.


---

### Answer by username_6 on 2015-01-02. Score: 1

i think [MPEG Streamclip](http://www.squared5.com/) can do this. It's free on mac and pc.


---

### Answer by username_7 on 2012-04-03. Score: 1

[Avidemux](http://fixounet.free.fr/avidemux/) should do the work.

1. Load File
2. Go to File -> Append and select File
3. To the left of the video window,
   * set video mode to Copy;
   * same for audio mode;
   * set format to MP4.
4. Go to File -> Save -> Video.

> **Comments:**
> **username_0**: This does what I am looking for, but it is causing the audio to go out of sync at the join point. I am going to try and join and mix the audio from a separate channel.  

---

