<p>
- This chapter provides a short primer on video files, formats and
- codecs – because it is often cause for confusion:
+ 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
+ A video file is a <dfn>container</dfn>. It usually contains one
+ <dfn>video track</dfn>, one or more <dfn>audio tracks</dfn>, and possibly <dfn>
+ subtitle</dfn> tracks, <dfn>chapters</dfn>…
+ The way 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
+ 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
+ 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
+ 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
+ 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
+ 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
+ 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—the
+ 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—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.
+ The export dialog includes presets for common format and codec
+ combinations (such as DVD, web-video,..). If in doubt, one of the
+ presets should be used.
</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.
+ As a 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 go back and use the original source of the video.
</p>
-