Streaming Video Editing
Once your streaming video production has been shot, the next stage is video editing. Part of the streaming video
editing process involves optimizing the video to keep the video image as still as possible. Such a video is ideal
for streaming to a variety of devices from hand held Personal Digital Assistants or PDA's to computers connected to
The reason for this is that relatively motionless video images, such as talking heads, compress very well and
therefore have a wider range of delivery options. The video dimensions can be kept small for PDA's and dialup, and
made larger for broadband connections.
Therefore, the optimizing process starts at the video editing stage. Try to eliminate scenes that involve a lot
of motion or perhaps crop the image so that background movement is minimized.
Alternatively, different versions of the same video can be made. This allows you to optimize the video for
various destinations. For instance, PDA's could receive a small dimension video that is relatively static, while a
larger dimension video with more motion could be prepared for broadband access.
Key frames are full frame images that are spaced evenly throughout the video file. The frequency of key frames
is the 'key frame rate' and may be expressed as every 'x' number of seconds or frames.
A key frame rate of every 3 seconds, for example, means that these full frame images only occur once every three
seconds. The in between frames are computed by calculating how many pixels move and how they change.
A low key frame rate, such as once every 3 seconds, provides a high level of compression, and conversely a high
key frame rate, such as one key frame for every 5 frames, results in lower level of compression and larger file
sizes. Therefore key frame rate is an important consideration when optimizing your video file for streaming.
Videos with a lot of motion require a higher key frame rate, which in turn means that they are better suited for
broadband connections. If your target audience is using dialup connections, a low key frame rate is needed, which
in turn means that motion in the video must be minimized.
Many video editing programs have built in conversion functions which allow you to encode the video in a variety
of streaming formats. All formats follow similar conventions, requiring you to choose several options that will
affect the size and image quality of the streaming video.
Most encoding software has a number of templates that set the options for specific targets such as broadband
Internet connections or video email. The templates are a good starting point and any of the settings can be
overridden manually for the best results.
There are encoding options for video dimensions, audio quality, frame rate and key frame rate. There may also be
a setting for image quality, with the higher settings for a better quality image, resulting in larger files.
All of the settings will affect the size and quality of the streaming video file. There is always a trade off as
you cannot get a full screen action packed streaming video without ending up with a huge file. Conversely you
cannot reduce file size without losing image quality or reducing the dimensions of the video.