Media

A standard file format is a file format that is recognised by other computer programs different to the one that was used to create it. This makes it possible to transfer a file to all programs that recognise the standard format. 

Standard File Formats for Graphics:

BMP is short for bitmap. It is a file format that uses a binary code to store the color of each pixel. This format does NOT use compression so the file sizes can be very large. They have a bit depth of over 24bits (they can produce over 16million colors). 

GIF is short for graphics interchange format is a file format that uses lossless compression. GIF uses a bit depth of 8 bits (max 256 colours) 

JPEG is short for joint photography expert group. It is a file format that uses lossy compression which means that quality of the image may be impaired. JPEG has a bit depth of 24bits (16milliin colours)

PNG (portable network graphics) is a file format for graphics that supports over 16million colours. it can provide lossless compression.

SVG (Scalable Vector Graphics) defines vector-based graphics in XML format. it is an image format for two-dimensional graphics with support for interactivity and animation.

The quality of graphics, video and sound files is determine by factors such as resolution, color depth and sampling rate. A computer has a limited storage capacity in main memory and backing storage. Compression techniques are used to reduce the size of large multi media files.

lossless compression= results in no reduction in quality

lossy compression= reduces the quality of the file

Need for compression

1. Compressed files require less storage space than uncompresse files on storage devices such as hard drives

2. Compressed files can be transmitted faster over the internet or a computer network as there is a smaller number of bits to be transfered.

There are several factors that affect the quality of graphics, sound and video files. However improving the quality has the disadvantage of increasing the file sizw since more bits need to be used to store the extra details.

Resolution is a measure of the size of the pixels in an image. High resolution graphics have a large number of pixels and low resolution graphics have a small number of pixels. High resolution graphics have better quality but larger file sizes than low resolution graphics.

colour depth is the number of bits that are used for the colour code of each pixel. The higher the number of bits, the more colours can be represented. Increasing the colour depth will give better quality colour graphics but will increase the size of the file.

Sampling rate the number of times that the sound is stampled per minute (digital sound is created by taking a stample of the sound many times every second).  A higher stample rate will result in a better-quality digitalised sound but will increase file size. 

Frame rate , the quality of video data is determined by the number of frames that are capture per second. Each frame has settings for resolution and color depth. The file size increases for higher frame rates, resolution and colour depth.