Why is the size of video very less than the size of its individual frames?

Hello everyone!! I have a small video. Its size on disk is 635 Kb. It is in .avi format. It has 3004 frames in it. All the frames are almost similar. When I save individual frame, each frame is 935bytes. So, the size of video should be atleast

3004*935 bytes = 2.6Mb. But why the video is only 635 Kb??

One more thing is, I have all these 3004 images in a variable of datatype cell in matlab. The size of that variable is around 6.5 Mb, but the sum of all the sizes of individual images is only 2.5 Mb. Why is it so?? Someone, please help..!!

Thanks in advamce..!!

Answer 1

[Jan]

You observe that the AVI files are compressed. Neighboring frames in a movie look very similar and the required size for storing the data can be reduced, when this similarity is exploited.

Please explain, how you measure the size of the variable and the size of the frames. Perhaps you save the frames as JPG images, which are compressed also. So currently the question does not contain enough information for a detailed answer.

[Viswas Guptha]

I measured the size of variable using 'whos' and the size of frame, yeah! by saving it in JPG..