User Interface Design

September 30, 2009


Week 6 lecture

User requirements stage by week 10/11

Required Documentation

Your interpretation of Dignans design brief

PACT analysis

Scenario of use

Evaluation 1

Design Approach

Type specimen exercise

Colour Palette

Style board

Design and Prototype stage – weeks 11-13

Test and Evaluate stage weeks 13-16

You do the detailed planning

Note the implementation stage is part of your web unit and you need to have a fully working site by week 15 at latest so you can evaluate it.

uidDesign

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Zoom Movie Project

September 29, 2009


Zoom into the College from outer space.

Base your ideas on the Powers of 10 movie.

Do some research and have a look at other similar examples.

Example 1

Example 2 using Google Earth

Example 3 From Quark to outer space

Use images or videos from online sources along with some video you have shot.

Your video needs to follow standard shot types ie long shot, medium close up , close up and so forth.

Check out my camera shots post

Include appropriate sound effects for each level of zoom.

How you end the movie is up to you.

Digital Audio Technology 1

September 21, 2009


Some useful concepts to help you to understand the technology behind working with digital audio.

Pulse Code Modulation

Pulse-code modulation (PCM) is a digital representation of an analog signal where the magnitude of the signal is sampled regularly at uniform intervals, then quantized to a series of symbols in a numeric (usually binary) code

Sampling

In signal processing, sampling is the reduction of a continuous signal to a discrete signal.

A common example is the conversion of a sound wave (a continuous-time signal) to a sequence of samples (a discrete-time signal).

Sample rate

When it is necessary to capture audio covering the entire 20–20,000 Hz range of human hearing, such as when recording music or many types of acoustic events, audio waveforms are typically sampled at 44.1 kHz (CD), 48 kHz (professional audio), or 96kHz. The approximately double-rate requirement is a consequence of the Nyquist theorem.

Quantization

Quantization can be thought of as mapping a signal with a continuous set of sample values to a set of discrete values.

Or,  its a way of approximating a very large range of values by a relatively small (“finite”) set of (“values which can still take on continuous range”) discrete symbols or integer values.  For example binary code in a computer.

For digital audio both of these steps (sampling and quantizing) are performed in analog-to-digital converters (ADC) with the quantization level specified in bits. This is known as resolution or bit depth of the sample.

The resolution of the converter indicates the number of discrete values it can produce over the range of analog values. The values are usually stored electronically in binary form, so the resolution is usually expressed in bits. In consequence, the number of discrete values available, or “levels”, is usually a power of two.

For example, an ADC with a resolution of 8 bits can encode an analog input to one in 256 different levels, since 28 = 256. The values can represent the ranges from 0 to 255.

Quantization introduces digital noise!  This is in addition to the noise that exists in all analog electrical circuits.

The Signal to Noise Ratio (SNR) is a ratio of the signal power to the noise power corrupting the signal.

There is a relationship between quantization noise and SNR that has direct effect on the qulity of the audio sample.