Mod2

PART II:
A file format is the structure in which information is stored (encoded) in a computer file. When dealing with video, a large amount of data is required to depict a video signal accurately, this information is often compressed and written into a container file. This section outlines digital video file formats: what they are, the differences between them, and how best to use them. There are many different formats for saving video, which can be confusing. Some formats are optimal for capture of video, and some are best used for editing workflow. Video files are significantly more complex that still image files. Not only is there a lot more different kinds of information inside them, but the structure of a video file is much more “mix-and-match”. You can tell a lot about most still image files by the file extension, but that does not hold for video. The file type (such as .MOV) is just a container, and could be filled with really low quality web video, or it might have ultra-high-quality 3-D video and five channels of theater-quality audio. In some ways, this is similar to the large number of raw file formats for still photography. You may have two files with the file extension CR2, but that does not mean they are equivalent. The “guts” of each of the files may have different resolutions, for instance, and a piece of software that can open one of these may not be capable of opening the other one. Container extensions include MOV, AVI, FLV, MP4, and MXF. Inside every video file container is the video and audio data. This data is created by a piece of software called a codec, short for compressor/decompressed (or compress/decompress). You can think of codecs as little helper applications that the program or the operating system uses to make or play the video file. Without the proper codec, a video file can’t be played by a computer. Video codecs are often proprietary and may involve additional licensing fees. Video editing software (and your operating system)...