user6285: If I wanted to cut the first 10 seconds off of a handful of videos(12 videos), is there a program that will open all of the videos at once and let me trim the first 10 seconds off of them all at the same time and then export the changes made to those videos all at once?
Instead of having to open each individual video then trim then export and rinse and repeat 11 more times times. 

user4943: Other people have already given a very good way to do these things one video at the time. But if, for whatever reason, you definitely need to do everything at once, you can use libav to do that.
Here is the example command with 4 files:
avconv -ss 10 -i 1.webm -ss 10 -i 2.webm -ss 10 -i 3.webm -ss 10 -i 4.webm \
  -map 0:0 -map 0:1 -c:a copy -c:v copy 1.mkv \
  -map 1:0 -map 1:1 -c:a copy -c:v copy 2.mkv \
  -map 2:0 -map 2:1 -c:a copy -c:v copy 3.mkv \
  -map 3:0 -map 3:1 -c:a copy -c:v copy 4.mkv

This assumes that in your files the video and audio streams are always the first two. Since this is not always the case this command can fail if you do not check first.

user2352: I don't know of anything that allows you to specify something like trimming  a certain amount off in batch, but you can do all of the rest with Adobe Media Encoder.

Open AME and drag all of the clips that you'd like to trim into the Queue panel.



Select all of the files in the queue and click on one of the preset links:



Choose a format and preset in the screen that pops up:



When you're done, click OK
Now click on the Preset link for each video and set the in point at 10sec and click OK



Repeat the last step for each of the videos
Click the run button  and all of your videos will be processed while you sip coffee!


user1247: If all you're doing is trimming the video, you may want to consider the command line tool ffmpeg. 
The -ss flag will allow you to set the in point for your trim. You can also set an out point on with the -t flag.
For example, the following command will take "name_of_movie.mp4", trim the first 10 seconds off, copy the audio and video codecs, and output the file as "name_of_movie_trimmed.mp4"
ffmpeg -i name_of_movie.mp4 -vcodec copy -acodec copy -ss 00:00:10 name_of_movie_trimmed.mp4

This should work for any format that ffmpeg accepts, which is pretty much all of them. If you'd like to script it, here's a starting point that I use for this very purpose. Edit the extensions for the type of file you use, and for the time you want, put it in a directory with the files you want to trim, and let it get to work.
#!/bin/bash
for file in *.mp4; do
name=${file%%[.]*};
ffmpeg -i "$file" -vcodec copy -acodec copy -ss 00:00:10 "$name trimmed.mp4"
done

There's a lot you can do with ffmpeg to automate some of the more tedious parts of working with video, so have a look around!

6285: <p>If I wanted to cut the first 10 seconds off of a handful of videos(12 videos), is there a program that will open all of the videos at once and let me trim the first 10 seconds off of them all at the same time and then export the changes made to those videos all at once?
Instead of having to open each individual video then trim then export and rinse and repeat 11 more times times. </p>
 4943: <p>Other people have already given a very good way to do these things one video at the time. But if, for whatever reason, you definitely need to do everything at once, you can use libav to do that.</p>

<p>Here is the example command with 4 files:</p>

<pre><code>avconv -ss 10 -i 1.webm -ss 10 -i 2.webm -ss 10 -i 3.webm -ss 10 -i 4.webm \
  -map 0:0 -map 0:1 -c:a copy -c:v copy 1.mkv \
  -map 1:0 -map 1:1 -c:a copy -c:v copy 2.mkv \
  -map 2:0 -map 2:1 -c:a copy -c:v copy 3.mkv \
  -map 3:0 -map 3:1 -c:a copy -c:v copy 4.mkv
</code></pre>

<p>This assumes that in your files the video and audio streams are always the first two. Since this is not always the case this command can fail if you do not check first.</p>
 2352: <p>I don't know of anything that allows you to specify something like trimming  a certain amount off in batch, but you can do all of the rest with Adobe Media Encoder.</p>

<ul>
<li>Open AME and drag all of the clips that you'd like to trim into the Queue panel.</li>
</ul>

<p><img src="https://i.stack.imgur.com/zQl51.png" alt="enter image description here"></p>

<ul>
<li>Select all of the files in the queue and click on one of the preset links:</li>
</ul>

<p><img src="https://i.stack.imgur.com/3ZMUS.png" alt="enter image description here"></p>

<ul>
<li>Choose a format and preset in the screen that pops up:</li>
</ul>

<p><img src="https://i.stack.imgur.com/dhQyb.png" alt="enter image description here"></p>

<ul>
<li><p>When you're done, click <kbd>OK</kbd></p></li>
<li><p>Now click on the Preset link for each video and set the in point at 10sec and click <kbd>OK</kbd></p></li>
</ul>

<p><img src="https://i.stack.imgur.com/KMUDB.png" alt="enter image description here"></p>

<ul>
<li><p>Repeat the last step for each of the videos</p></li>
<li><p>Click the run button <img src="https://i.stack.imgur.com/fywnn.png" alt="enter image description here"> and all of your videos will be processed while you sip coffee!</p></li>
</ul>
 1247: <p>If all you're doing is trimming the video, you may want to consider the command line tool <a href="http://ffmpeg.org" rel="nofollow">ffmpeg</a>. </p>

<p>The -ss flag will allow you to set the in point for your trim. You can also set an out point on with the -t flag.</p>

<p>For example, the following command will take "name_of_movie.mp4", trim the first 10 seconds off, copy the audio and video codecs, and output the file as "name_of_movie_trimmed.mp4"</p>

<pre><code>ffmpeg -i name_of_movie.mp4 -vcodec copy -acodec copy -ss 00:00:10 name_of_movie_trimmed.mp4
</code></pre>

<p>This should work for any format that ffmpeg accepts, which is pretty much all of them. If you'd like to script it, here's a starting point that I use for this very purpose. Edit the extensions for the type of file you use, and for the time you want, put it in a directory with the files you want to trim, and let it get to work.</p>

<pre><code>#!/bin/bash
for file in *.mp4; do
name=${file%%[.]*};
ffmpeg -i "$file" -vcodec copy -acodec copy -ss 00:00:10 "$name trimmed.mp4"
done
</code></pre>

<p>There's a lot you can do with ffmpeg to automate some of the more tedious parts of working with video, so have a look around!</p>
