NED11: Module 11

Video on the web

Video has the ability to show powerful and attention grabbing moving images. Video integrated effectively into the project adds a sense of dynamic energy. Video that plays slowly, runs too long, or has little purpose except to function as 'eye-candy' can detract from the interactive experience. Tips:

• Show information quickly, easily and concisely in a way that text or still images might not
• If it's hard to explain in words or pictures, consider using video, i.e. rolling dough
• Add realism to your document
• Use for artistic purposes
• Show places, people, animals or events that most individuals would never have the opportunity to see
• Add celebrity and on-the-spot interviews, bringing real life experiences to the document, i.e. interviewing a well-known chef
• Use a tripod and don't move the camera too fast
• Use tight-close-ups when possible 
• Plan ahead of time and use quality material
• Pay close attention to your backgrounds
• Don't shoot exceedingly dark or light backgrounds
• Always leave space around your subject
• Choose music that isn't too wide ranging (to help with compression)
• Leave some time at the start and end of each shot
• Leave 15 seconds at the beginning and 30 seconds at the end of your video
• Choose how you will capture your video digitally (for web or CD)
• Chose 8-15 frames per second. The quality of each frame is more important than the number of frames per second
• Go no bigger than 320 x 240 pixels at 10 frames per second
• Configure the hue, saturation and brightness up front - this will save you a lot of time in editing

Downloading movies and animation can be very time consuming. You have two options - either link the video to your webpage for download and playback; or choose from a variety of streaming solutions.

Video formats:

• AVI (audio/video interleaved) was introduced by Microsoft in 1992 and plays back faster and smoother than any other format by interleaving the audio data with every video frame
• QuickTime was introduced by Apple in 1991 as a video file format and multimedia architecture to handle time-based media. It has become the industry standard for desktop video production
• MPEG is a set of multimedia standards created by the Moving Pictures Expert Group. It supports video, audio and streaming and uses an extremely high compression rate with little loss in quality

Compression techniques:

Keep your files as small as possible by reducing the frame rate and compressing the finished file. Codecs (abbreviation for compression/decompression) allows videos to be reduced to a reasonable file size. Recommended software tools include Movie Cleaner Lite, QuickEditor (Mac) or VidEdit for Windows. A codec will compress the file and then decompress it for playback. Video codecs decompress the video on the fly - allowing the client to view the file from its compressed original. 

A good audio track can go along way toward distracting people from a low frame rate. jerky sound is actually much more jarring than a discontinuous picture - so don't' skimp on the audio. A mono 8 bit sound at 22.05kHz is decent for music, and much more than adequate for voice. 

Hardware codecs are the most efficient way to compress and decompress video files, however they are expensive but delivery high quality video footage as long as viewers have the same decompression device. Software codecs are less expensive and freeware versions are readily available. But software codecs are CPU intensive and take a long time to analyse and compress files.