Fichas
Sounds, Videos, Images and Compression
Fichas del conjunto (24)
- 1What is the definition of image resolution?No. of pixels per inch of an image
- 2What's screen resolution?Number of pixels the screen has, typically the number of pixels per row multiplied by the number of pixels per column
- 3What are pixelsAre the smallest areas that could be referred to in an image, this area often holds a colour and a corresponding binary value.
- 4Bitmaps vs Vectors?Bitmap: Group of pixels placed in specific areas with a specific binary value representing its colour
Vector Graphics: Images created using mathematics and geometric quantities, such as lines, curves etc. They are scalable and their values are stored mathematically. - 5Adv and Disadv of Bitmap graphicsAdv:
-Bitmaps are better than vectors for photo editing
-Bitmaps require less processing effort
Disadv:
-File size changes when scaling is done
-Distort when scaled - 6Adv and Disadv of Vector graphicsAdv
-Vectors require more processing efforts
-Good for logo designs
Disadv
-File size does not change when scaled
-Does not distort when scaled
-Not good for photo editing - 7What is lossless compressionA non-destructive method
Compresses file(s) without losing any data
Example: Run Length Encoding (RLE) - identifies repeated data and stores it in a bank as a single datum with a repeated count - 8What is lossy compressionCompression that removes unnecessary data to reduce file size
A destructive method
e.g. .mp3, .jpeg - 9What is a typical image size calculation?Image has height=1000, width=800 and has 16BPP. What is the file size?
Image resolution: 1000x800=800000px
since there are 800000px and each pix is 16 bit:
800000x16=12800000bits=1.6MB - 10What is a sound sample rateSample rate - measured in hertz, how many times a sound's analogue amplitude is measured (sampled) per second
- 11What is a sound sampleConverting analogue sound into digital format for computers, turning sound waves into binary values by MEASURING THE AMPLITUDE of the sound at regular time intervals
- 12What is sample resolutionAlso known as bit depth, it's the no. of bits available encode/assigned to a sample. Higher resolution=smaller error quantization, therefore less sound distortion
- 13What is the equation to work out the bit rate of a song?bit rate = sample rate*sample resolution
- 14What is interlacedMethod that splits each image into two fields, odd number fields and even number fields, therefore each frame will only display half an image. Denoted by letter "i", at some frame rate (e.g. 1080i) images will collectively form a video, commonly used for TV broadcasting
- 15What is progressive capture and replayProgressive video capture displays each image entirely on each frame, therefore the higher the frame rate, the smoother the movements and better video quality. A lot of videos found on YouTube and in cinemas are progressive.
- 16The two types of video compression?Spatial and Temporal
- 17What is spatial compression?Spatial compression is similar to image or sound compression in that it takes the repeated areas of a frame and group them together and assigning them with some code
- 18What is temporal compressionTemporal compression looks at the video as a whole and reduces unnecessary, repeated frames and therefore making the entire video smaller in file size.
- 19What is the multimedia Container format?Multimedia Container Format (MCF) was a project initially intended to self suffice a user to video features all in one file (audio, subtitle, menus, languages etc.) and so without having to rely on third party services. The project was abandoned in 2004 and is succeeded by Matroska files (.mkv) which is an open, free video container format that stores common multimedia contents.
- 20What is bit streaming?Bit streaming refers to the act of delivering data from the owner to the client over a communication line and the client receiving it and experiencing it part by part before the entire file transfer is complete. Bits arrive in the same order as they are sent
- 21What is live streamingLive streaming is similar to on-demand streaming except the event is happening as it is being streamed. This will require some sort of capture/streaming source (e.g. a camera), an encoder, a media publisher and a content providing network. Cannot be paused.
- 22Applications of live streaming and its drawbacksonline lectures, live viewing of sports, of concerts etc. Drawbacks include the need for bandwidth, CPU Power, which together result in latency.
- 23Lossless and lossy file formats for images?Lossless: .raw, .png, .bmp
Lossy: .jpeg, .gif - 24Lossless and lossy file formats for media?Lossless: .wav, .flac, .alac
Lossy: .mp3, .mp4, .ogg
Información
- Descripción
- Advanced Level (A- Level) (Information Representation) Computer Science Fichas sobre Sounds, Videos, Images and Compression, creado por TS P el 24/12/2015.
- Creado por
- TS P
- Visitas
- 23
- Valoración