Chapter 3 - Part 2 Flashcards
Analogue
Has no discrete value and varies continuously. Represented as a wave
Bit depth
No. Of bits used for each sample
Sampling rate
No. Of samples taken per second
Sample
Measure of amplitude @ a given time
How is analogue converted to digital
Analogue to digital converter will take in the sound wave and convert it to electrical signals.
Higher sample rate does what to quality?
Higher quality of sound
Units for sample rate
Hertz (Hz)
File size of single channel sound file (bits) = …
sampling rate x sample resolution x seconds
Data compression
Reducing the number of bits needed to store data
Advantage of data compression
Sending files takes less time to transfer
If on a web page, then it will take less time to load and open
Ensures that it can be received on anyones’ device
2 types of data compression
Lossy
Lossless
Lossy compression
Parts of a file are lost when compressed and can not be retrieved
Examples of lossy compression
JPEG for images
MP3, mp4 and ogg for sound
WMV and mpeg for Videos
Lossless data compression
Reduces the file size without Losing any data
Examples of lossless compression
PNG for images
Flac and alac for sound
Reasons for using lossy compression
Videos can NOT be compressed with lossless
Lossy can compress files to a smaller size than lossless
Run length encoding (RLE)
Method of LOSSLESS compression. Groups together any binary
E.g. 00001100000111111
becomes…
40 21 50 61
Huffman coding
Method of LOSSLESS compression. Reduces the number of bits required to store data
Extended ASCII uses how many bits
8
