12 ITM - Core Flashcards
Differentiate cel-based and path animation.
In cel-based animation, a series of progressively different graphics are drawn on each frame individually of an animation (e.g. stop motion). Path animation, however, involves changing the location of an image along a predetermined path during a specified amount of time (e.g. bouncing ball in Adobe Flash).
Differentiate import and export in video editing
Import refers to transferring audio and video files into a project. Export is the process of converting the project into a video format. e.g. mp4 (pg45)
Describe how titles and transitions are used during postproduction
Titles are often used to introduce a video, finish off a project and provide credits. Transitions combine scenes or shots together. e.g. dissolve, cut, fade (pg45)
What makes the GIF file format distinct when it comes to its capabilities with animation?
GIFs allow the looping of animation. This involves automatically repeating the animation over and over again indefinitely, often seamlessly.
Identify an advantage and a disadvantage of wire frame modelling.
Wireframes are representations of 3D objects, created by specifying each edge of the physical object by using straight lines or curves.
3D wire frame allows users to construct and manipulate solids and solid surfaces. The 3D solid modeling technique efficiently draws higher quality representations of solids than the conventional line drawing.
Since wire-frame renderings are relatively simple and fast to calculate, they are often used in cases where a high screen frame rate is needed. For instance, when working with a particularly complex 3D model, or in real-time systems.
https://en.wikipedia.org/wiki/Wire-frame_model
How is sound synchronised?
A clapperboard clap noise that is recorded at the start of each scene can be used to synchronise audio during post production(pg45)
Volume
volumes are measured in decibels – a decibel is a logarithmic scale (each 10dB increase is a 10x increase in sound pressure). 20dB is about the volume of a whisper, 140dB is that of a jet airplane taking off next door. (pg44)
The volume of a perceived sound can be measured by its amplitude. Sounds with greater amplitude will produce greater changes in atmospheric pressure from high pressure to low pressure. Amplitude is almost always a comparative measurement, since at the lowest-amplitude end (silence), some air molecules are always in motion and at the highest end, the amount of compression and rarefaction though finite, is extreme
http://www.indiana.edu/~emusic/acoustics/amplitude.htm
Frequency
The frequency of a wave refers to how often the particles of the medium vibrate when a wave passes through the medium.
1 Hertz = 1 vibration/second
The sensation of a frequency is commonly referred to as the pitch of a sound. A high pitch sound corresponds to a high frequency sound wave and a low pitch sound corresponds to a low frequency sound wave.
f ∝ pitch
http://www.physicsclassroom.com/class/sound/Lesson-2/Pitch-and-Frequency
Mono/stereo/surround sound
Refers to no. of channels
Stereo or surround sound-two or more independent signals are captured through separate channels from different microphones. Therefore sound captured has more depth.
Stereo refers to 2 channels L and R
Surround is notated to show no. of channels
Mono captures entire sound signal in one channel (pg44)
Converting analogue to digital sound
Sound is a continuous wave form and needs to be converted into discrete samples by an Analog to Digital Converter (ADC). The sound is sampled and its amplitude is stored. Each sample uses a fixed number of bits (sample size) which determines the quality of the data.
http://music.tutsplus.com/articles/encyclopedia-of-home-recording-bit-depth–audio-12204
SAMPLE RATE: Measured in kHz,the intervals of digitisation, the smaller the interval, the closer the digitised sound is to the analogue
SAMPLE SIZE: Determine the no. of bits used to store the volume of sound at a particular interval. Increasing the number of bits also increases the maximum dynamic range of the audio recording, in other words the difference in volume between the loudest and softest possible sounds that can be represented.
NO OF CHANNELS: refers whether the audio is mono/stereo/surround (pg 44)
http://manual.audacityteam.org/man/digital_audio.html
Sampling
Sampling involves taking snapshots of an audio or video signal at very fast intervals, usually tens of thousands of times per second. The quality of the digital signal is determined largely by the sampling rate, or the bit rate the signal is sampled at. The higher the bit rate, the more samples are created per second, and the more realistic the resulting audio or video file will be. For example, CD-quality audio is sampled at 44.1 kHz, or 44,100 samples per second.
calculate audio size
sample rate X sample size X no. of channels X seconds = bits
Relationship to file size: File compression
Most file compress data using lossy technique to reduce file size.
Intraframe compression (video): a-frame coding refers to the fact that the various lossless and lossy compression techniques are performed relative to information that is contained only within the current frame, and not relative to any other frame in the video sequence
Interframe compression (video): This kind of prediction tries to take advantage from temporal redundancy between neighboring frames allowing to achieve higher compression rates. i.e. it looks only for changes in between frames, good for those with same background (e.g. newsreaders).
Audio File formats
WAV :uncompressed sound data, used by windows (microsoft)
AIFF:( Audio Interchange File Format) : uncompressed digital audio format. AIFF is historically used by MACS
MP3: lossy compressed to reduce file size
WMA: (Windows Media Audio) is a proprietary Microsoft format developed to improve MP3.
MIDI is going to have its own flash card kek
MIDI
MIDI was invented so that musical instruments could communicate with each other and so that one instrument can control another. When a note is played on a MIDI instrument, it generates a digital signal that can be used to trigger a note on another instrument,
MIDI also enables other instrument parameters to be controlled remotely. Synthesizers and samplers contain various tools for shaping a sound
MIDI events can be sequenced with computer software, or in specialized hardware music workstations
MIDI carries event messages that specify notation, pitch and velocity, control signals for parameters such as volume, vibrato and tempo.
BEST EXPLANATION - starts approx. 5mins 30 secs: https://www.youtube.com/watch?v=SUUxmJ84dnI kek
