MPEG-1 Video File Format
According to the Wikipedia page on the subject, the "MPEG-1 Video exploits perceptual compression methods to significantly reduce the data rate required by a video stream. It reduces or completely discards information in certain frequencies and areas of the picture that the human eye has limited ability to fully perceive. It also utilizes effective methods to exploit temporal (over time) and spatial (across a picture) redundancy common in video, to achieve better data compression than would be possible otherwise."
MPEG-1 files use progressive encoding, which requires viewers to download a video file in its entirety before being able to view any of its content.
MPEG-1 files also use temporal compression, which reduces the amount of data stored within a sequence of frames by employing key frame technology. Rather than storing every pixel in each frame, temporal compression stores a key frame, the only the information which is changing between key frames. Quality of the footage can be significantly lower than progressive encoding formats as a result of temporal compression being used. Temporal compression also has the drawback of not allowing future editing of the file.
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