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. 

NED11: Module 10

Audio on the web
Background music can set an emotional tone, dialogue and narration can supplement written passages. Sound effects can also be used for interactive functions suck as button clicks.

Terminology of audio:

• AAD - Analog Record, Analog Produce and Digital Master
• ADD - Analog Record, Digital Produce and Digital Master
• DDD - Digital Record, Produce and Master (this format is the cleanest
• Bits are like digital information - zeros and ones. The more bits the more accurate the sound reproduction
• Sample Rate and Bit Depth - the higher the sample rate and bit depth recorded, the better the quality 8 bit sound uses 256 amplitude levels while 16 bit sound uses 32,768 amplitude levels
• Compression (ie MPEG) uses lossy compression that strips out sounds that are not discernible to the human ear to achieve very high compression ratios while maintaining near-original sound quality.

Audio Tips and Tricks:

• Keep everything DDD if you can
• Make sure you normalise your files. This trims off amplitudes above or below certain levels. and leaves you with a steady and stable signal
• Use a good pair of headphones or speakers while editing sounds
• Equalise your files, this ensures proper ratio of treble to bass. Be careful with bass - some smaller computer speakers can't handle it very well
• Test your audio on different systems
• Keep it simple, resist the temptation to get carried away with all the special effects
• Use the best equipment possible 

How to keep sound files small for quicker downloads:

• Keep the length of your audio clips short - the shorter, the better
• Limit the number of channels you use - mono is half the size of stereo
• Reduce your bit depth to only what you need
• Keep your sampling rate down - 22.05kHz is half the size of 44.1kHz
• Voice only files can be reduced down to 8kHz without any discernible loss in quality while music will sound acceptable at 22kHz

Googling 'sound effects' produces many websites where you can obtain sound effects, many are free. However if you decide to record sound effects yourself, some software suggestions are QuickTime, Bias Peak, Sonic Foundry Sound Forge and GoldWave Audio.

Using sound in your document:

• Let the user have the option of turning off or adjusting the sound volume
• Choose the right voice talent for any planned narration. The wrong voice. accent or inflections can seem inappropriate or even grating to the user
• Choose sound effects wisely, and only use those sounds that add meaning to your project

Online delivery strategies:

Non-streaming audio must be downloaded before playback and usually results in larger files. File formats include:

• WAV - originally developed as the standard audio format for Windows but is now supported on Macs. Most commonly used at 8kHz to 11.025kHz at 8 or 16 bit
• AIFF was developed as Mac standard but now supported on PC. Most commonly used at 8kHz to 11.127kHz at 8, 16 or 32 bit. Similar performance to WAV
• MPEG - maintains pristine sound quality at compression rates as high as 10.1. The higher the number, the more complex the coding and the more powerful a processor you will need to compress and decompress
• MIDI was originally developed as a standard way for electronic instruments to communication with each other. They are a mathematical command that describes a series of notes. MIDI files are incredibly compact and are capable of packing a minute of music into just 10K which is 1000 times smaller than one minute WAV file. Unfortunately MIDI's can only contain notes, not real sounds.

Non-streaming advantages are they don't require a special server and they are simple to create audio flew in standard formats. The disadvantages are file size which can result in unacceptably long wait times for files to download and start playing. Because the audio file is being downloaded to the user's computer - it is difficult for artists and publishers to limit distribution and protect copyright.

Streaming Audio begins playback almost immediately. There are 3 components to streaming audio - the Encoder (used to create the file format), the Player (used by the user to hear the audio) and the Server Software (used to provide optimum streaming). Other advantages are the sound quality doesn't need to be severely sacrificed and artists and publishers can control distribution and protect copyright because the file doesn't get copied to the user's computer. The disadvantages however are the high cost of server software and the sound quality and stream may be affected by low speed or inconsistent Internet connections.