Module 1. Multimedia Concepts

Please check the right complete answers below.
Those are very long answers, but you will get a complete picture if you were confused about some of them.


1. A bitmap is a graphic file whose information is stored as a grid of pixels.
The term bitmap comes from the computer programming terminology, meaning just a map of bits, a spatially mapped array of bits.
The picture is built up from these dots. The smaller and closer the dots are together, the better the quality of the image but the bigger the file needed to store the data. If the image is magnified it becomes grainy as the resolution of the eye enables it to pick out individual pixels.
Bitmaps are also referred to as raster graphics.
Some common file formats for bitmaps are .bmp, .jpeg ,.tiff, .gif, .png, .psd.

2. Resolution is the interpreter between the physical world of inches and the digital world of pixels.
When you scan an image, the scanner translates inches into pixels using resolution. When you print an image, the printer translates pixels into inches using resolution.
The resolution of a screen is 72 dpi, which means dots (or pixels) per inch. This means that there really isn’t any point of trying to look at things in a higher resolution than the screen has because it will just display in the same way as it would if you were looking at it in the lower resolution.
Printing resolution, however, must be quite a bit higher because it takes more information to print an image than it does to view it on the monitor. A typical desktop printer needs between 150 and 300 dpi in order to print the image correctly.

3. Flash files tend to be small because it saves the graphic information in a vector format.
Vector graphics files store the lines, shapes and their properties that make up an image as mathematical formulae.
A vector graphics program uses the mathematical formulae to construct the screen-image by building the best quality image possible, given the screen resolution, from the mathematical data.
The mathematical formulae determine where the dots that make up the image should be placed for the best results when displaying the image. Since these formulae can produce an image scalable to any size and detail the quality of the image is only determined by the resolution of the display and the file size of vector data generating the image stays the same.
Printing the image to paper will usually give a sharper, higher resolution output than printing it to the screen but can use exactly the same vector data file. And the file is much smaller in size.

4. DV resolution is 720 X 480 pixels, but full screen digital video is 640 X 480 pixels.
The term "full-screen digital" video is mostly used by web developers, since for a long time, short bandwidth forced video over the web to be smaller than that size.
This format works with square pixels (the files don't have to be output into a broadcast video device.
640X 480 is the resolution of a 13" monitor. This was considered the standard size monitor for working screens in the 90s.
A typical format for video over the web was traditionally 160 X 120 or 320 X 240, also called "half-screen video". Notice that the AREA of "half video"(320X240) is actually a fourth of "full-video"(640X480).
We use those standards because a video file (also based on pixels), works best when you remove half the pixels in the horizontal direction and half the pixels in the vertical one (throwing every other pixel away).

Digital video has a quirk that many of its formats employ “non-square” pixels.
This means its pixels are supposed to be stretched or squashed by a specific amount when played back on a television or a video monitor.
In contrast, computer monitors have square pixels. As a result, much digital video looks odd when viewed on a computer.
Therefore, it is essential to understand these pixel aspect ratio (PAR) issues when creating graphics.

The DV specification defines both the codec and the tape format.
Its smaller tape form factor Mini DV has since become a standard for home and semi-professional video production.
The DV codec works with a resolution of 720X480 pixels, and it uses non squared pixels (with a 0.9 aspect ratio). The reason to this was to match analog TVs, that also worked with rectangular pixels.
NTSC video works at a frame rate of 29.9 frames per second and it works with 480 lines of resolution, this is why both formats work with 480 pixels of vertical resolution.
The 720 pixels across might be due to the rectangular proportion of the pixels, it might also have been an strategy to pair up with PAL (the European Video standard) that always worked with 720 pixels of resolution across.

DV is not a wide screen format. It still works with a 4:3 aspect ratio. HDV on the contrary, is a wide screen format that uses a 16:9 aspect ratio. HDV is High definition video.
Its standard resolutions are 1280X720 pixels and 1920X1080 pixels. They are usually called by their vertical resolution. You might have heard of 720p or 1080p screens, when buying flat-TV-screens.

5. An mp3 is a very size-efficient sound file format.
Since 1998 the MP3 standard has become more and more important, and an enormous success. MP3 is a system to give a huge compression of digital sound files. The compression is lossy (i.e. musical details are cut away). Yet MP3 delivers a sound quality (almost) as good as uncompressed CDs, due to the very intelligent psycho-acoustic algorithm reducing the file size.
The MP3 format is very versatile; it can be hosted on any storage media and can be transferred on demand over the Internet.
These files can be played using a player like iTunes, Winamp, MusicMatch or Windows Media Player. The MP3 files can also be decoded and used for CD-recording.