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+<p>
+  This chapter provides a short primer on video files, formats and 
+  codecs – because it is often cause for confusion:
+</p>
+
+<p>
+  A video file is a <dfn>container</dfn>. It usually contains one 
+  <dfn>video track</dfn> and one or more <dfn>audio tracks</dfn>. 
+  How these tracks are stored in the file is defined by the 
+  <dfn>file format</dfn>. Common formats are 
+  avi, mov, ogg, mkv, mpeg, mpeg-ts, mp4, flv, or vob.
+</p>
+<p>
+  Each of the tracks by itself is encoded using a <abbr
+  title="Coder-Decoder"><dfn>Codec</dfn></abbr>. Common video codecs 
+  are h264, mpeg2, mpeg4, theora, mjpeg, wmv3. Common audio codecs are
+  mp2, mp3, dts, aac, wav/pcm.
+</p>
+<p>
+  Not all codecs can be packed into a given format. For example the 
+  mpeg format is limited to mpeg2, mpeg4 and mp3 codecs (not entirely true). 
+  DVDs do have stringent limitations as well. The opposite would be .avi; 
+  pretty much every audio/video codec combination can be contained in an avi 
+  file-format.
+</p>
+<p>
+  To make things worse, naming conventions for video codecs and formats are 
+  often identical (especially MPEG ones) which leads to confusion.
+  All in all it is a very wide and deep field. Suffice there are different 
+  uses for different codecs and formats.
+</p>
+
+<h2>Ardour specific issues</h2>
+<p>
+  Ardour supports a wide variety of video file formats codecs. More 
+  specifically, Ardour itself actually does not support any video at all 
+  but delegates handling of video files to <a
+  href="http://ffmpeg.org/">ffmpeg</a>, which supports over 350 different 
+  video codecs and more than 250 file formats.
+</p>
+<p>
+  When importing a video into Ardour, it will be <dfn>transcoded</dfn> 
+  (changed from one format and codec to another) to avi/mjpeg for internal 
+  use (this allows reliable seeking to frames at low CPU cost &mdash; the 
+  file size will increase, but hard disks are large and fast).
+</p>
+<p>
+  The export dialog includes presets for common format and codec 
+  combinations (such as DVD, web-video,..). If in doubt use one of the 
+  presets.
+</p>
+<p>
+  As last note: every time a video is transcoded, the quality can only get 
+  worse. Hence for the final mastering/<abbr 
+  title="Multiplexing Audio and Video">muxing</abbr> process, one should 
+  always to back and use the original source of the video.
+</p>
+