user1567: My camera phone takes video in 3gp format. I've inadvertently taken a video sideways and want to turn it 90 degrees for upload to services such as YouTube and Facebook. 
What software package can I use on Windows to do this, or is there another option?  I've looked at the YouTube upload interface and it doesn't have an option to turn the video.

user3476: The following will flip a video 90 degrees clockwise:
ffmpeg -i input.3gp -filter:v 'transpose=1' -c:a copy \
-c:v libx264 -crf 22 -preset veryfast output.mp4

To flip it 90 degrees anti-clockwise, use 'transpose=2'. See the documentation for more information. Note that this will require a fairly up-to-date version of ffmpeg.

user1532: You could use Windows Live Movie Maker, which is free with Windows Live Essentials.  Here is a tutorial on how to do it.
It looks like Windows Movie Maker doesn't have native support for the 3GP format, but you should be able to download a CODEC for it.
For Mac users, iMovie is the equivalent.

1567: <p>My camera phone takes video in 3gp format. I've inadvertently taken a video sideways and want to turn it 90 degrees for upload to services such as YouTube and Facebook. </p>

<p>What software package can I use on Windows to do this, or is there another option?  <strike>I've looked at the YouTube upload interface and it doesn't have an option to turn the video.</strike></p>
 3476: <p>The following will flip a video 90 degrees clockwise:</p>

<pre><code>ffmpeg -i input.3gp -filter:v 'transpose=1' -c:a copy \
-c:v libx264 -crf 22 -preset veryfast output.mp4
</code></pre>

<p>To flip it 90 degrees anti-clockwise, use 'transpose=2'. See <a href="https://ffmpeg.org/ffmpeg-filters.html#transpose" rel="nofollow">the documentation</a> for more information. Note that this will require a fairly up-to-date version of ffmpeg.</p>
 1532: <p>You could use <a href="http://windows.microsoft.com/en-GB/windows7/products/features/movie-maker" rel="nofollow">Windows Live Movie Maker</a>, which is free with Windows Live Essentials.  <a href="http://www.youtube.com/watch?v=HlqqlS8CDv4" rel="nofollow">Here</a> is a tutorial on how to do it.</p>

<p>It looks like Windows Movie Maker doesn't have native support for the 3GP format, but you should be able to download a CODEC for it.</p>

<p>For Mac users, <a href="http://www.apple.com/ilife/imovie/" rel="nofollow">iMovie</a> is the equivalent.</p>
