Videos, images, files, they all take up an enormous amount of space. This is especially the case with video footage, which can consume gigabytes of memory in minutes. So it is important that the video is compressed before it is distributed onto the web or even sent via email. There are two kinds of compression: lossy and lossless.
Lossy compression often renders files smaller than their original state. Sometimes this translates to lower quality files, due to the large amount of data that has been lost. However, the plus side to this is that the file is considerable smaller, making it convenient to download, send or upload. While a lot of visual quality can be lost, the lossy compression can provide good quality images, which are difficult to distinguish against the higher quality compressions. An example of this is with the MPEG-2 format, which is a DVD compression that produces files 15 to 30 times smaller, but we still tend to see DVD as having a high-quality picture.
Lossless compression is exactly what it says on the tin, whereby no information is lost. This produces the highest-quality pictures, as well as the biggest file sizes. This has its uses and its drawbacks. Lossless compression is useful if the video editor wanted to transfer the files from one computer to another, by using lossless, they will not lose any picture quality. However, a drawback of lossless compression is its inconvenience. Because of the huge file sizes it is not ideal to send, download or upload lossless content because it will often exceed the limit available or take an extremely long time.
Difference between a file format and a video format-
The details of a file are held and stored inside the file format. Essentially the file format is a box that carries the information and determines how the data within the file is organised.
Examples of multimedia file formats:
JPEG, TIFF, MPEG, GIFF, AVI, MOV
The video format is the flavour of compression that is used on the video. Where the file format is concerned about being the container of the data, the video format is the element that goes inside the container. As such, the video format decides the type of player that will be able to understand and play the video file, as well as the quality of the video.
There is no one format that works on everything. Before compressing a video, it is important to know the platform it is going to play on. For instance, if a video has plans to be shown on a Blu-ray DVD disk, then the appropriate format would be H.264-Blu-ray, as this is a modern video format that is specific to Blu-ray platforms. However, if the intentions of the video were to be played on YouTube, it would be ideal to choose the H.264 file format with the YouTube video compression, as this will suit the needs of a YouTube video. Like wise, there are compression formats that are email specific, which are convenient if the video needs to be sent via email or messaging.
Things to consider when choosing a file format and codec:
Quality and bit depth
Rendering speed (encoding)
File size (zipped)
File size (unzipped)
Each of these contributes towards the rendering and downloading speeds of a video and how it will be played. For instance, a zipped file will generate a much smaller file size to that of an unzipped file. This makes it convenient when transferring files across the web. However, not all programs have sipped file compatibility, making the unzipped file the appropriate choice. Plus, factors such as how good does the video have to be, establish what the quality can be.