Paper 1 - Storing sound and Compression

What are analogue signals

pieces of continually changing data

Sound is recorded by a microphone as an ..

analogue signal

what do analogue signals need to be converted into so that computers can read and store sound

digital data

what is the process of converting analogue to digital called

sampling

How can the quality of a digital sound file be improved

increasing sample rate

increasing bit depth

What factors affect the size and quality of sound files

sample rate

bit depth

duration

what is the bit depth

the number of bits available for each sample

increasing the bit depth means the digital file …

picks up quieter sounds

what is data compression

when we make the file size smaller while trying to make the file as true to the original as possible

What are the advantages of compression

files take up less storage space on a device

streaming and downloading from the internet is quicker as they take up less bandwidth

can send emails and bypass the attachment size restrictions

Lossy compression works by…

permanently removing data from the files limiting the number of bits the file needs and so reduces the file size

Lossless compression…

makes the file smaller by temporarily removing data to store the file and then restores it to its original state when it’s opened

What are the advantages of Lossy compression

Greatly reduce file size so more files can be stored

Take up less bandwidth so can be downloaded and streamed more quickly

Commonly used meaning lots of software can read lossy files

What are the disadvantages of lossy compression

Loses data so the file cant be returned back to normal

Can’t be used on text files as they need to retain all their information

worse quality than the original

what are the advantages of Lossless compression

No reduction in quality

Can be decompressed

Can be used on text and software files

What is a disadvantages of lossless compression

Only a slight reduction in file size so it will still take up quite a lot of space on your device