A quick and dirty explanation (through C code) of why we need video compression techniques

VideoFrameSizes.c

/*
 * Project Name:            VideoFrameSizes
 * Solution Name:           MandelbrotCalc
 * Original creation date:  24/03/2011
 * Edit date:               19/01/2013
 * Programmer name:         Jamie Taylor (aka "GaProgMan")
 * File name:               VideoFrameSizes.c
 *
 * Purpose of the project:
 *   To underpin the reasons why video compression exist
 * by showing how much memory is required to store a video
 * with the following attributes:
 *  Resolution (pixels): 640*480
 *  Colour depth:        24-bit
 *  Frame rate (fps):    25
 *
 *
 *    GNU Copyright information
 *    Copyright 2011 Jamie Taylor <jamie@taylorj.org.uk>
 *
 *    This program is free software; you can redistribute
 *        it and/or modify it under the terms of the GNU General
 *        Public License as published by the Free Software
 *        Foundation; either version 2 of the License, or (at
 *	your option) any later version.
 *
 *	This program is distributed in the hope that it will
 *	be useful, but WITHOUT ANY WARRANTY; without even the
 *	implied warranty of MERCHANTABILITY or FITNESS FOR A
 *	PARTICULAR PURPOSE.  See the GNU General Public
 *	License for more details.
 *
 *	You should have received a copy of the GNU General
 *	Public License along with this program; if not, write
 *	to the Free Software Foundation, Inc., 51 Franklin
 *	Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

#include <stdio.h>

int main(int argc, char** argv) {
  float _width, _height, _pixelsPerFrame, _colourDepth, _bitsPerFrame,
       _frameRate, _bitRate, _length, _videoSize = 0;
  
  /* These values have been chosen as test values
  * because they produce answers that are easy to
  * predict. Also, they represent a compressed AVI
  * rip of a Pal DvD source.
  * 25 frames a second, 24 bit colour, 640 * 480,
  * and 1 hour in length
  */
  _width = 640;	   _height = 480;  _colourDepth = 24;
  _frameRate = 25; _length = 3600;
  
  // pixels per frame
  
  /* Commented these lines out as I'm testing the internal
  * logic with known values, first
  * printf("Enter the width for the video in pixels: ");
  * scanf("%f", &_width);
  * printf("Enter the height for the video in pixels: ");
  * scanf("%f", &_height);
  */
  _pixelsPerFrame = _width * _height;
  printf("A video with %f pixels wide by %f high, ", _width, _height);
  printf("has %f pixels per frame\n", _pixelsPerFrame);
  
  //bits per frame
  
  /* Commented these lines out as I'm testing the internal
  * logic with known values, first
  * printf("Enter the colour depth for the video in bits: ");
  * scanf("%f", &_colourDepth);
  */
  _bitsPerFrame = _pixelsPerFrame * _colourDepth;
  _bitsPerFrame = (_bitsPerFrame/1024)/1024;
  printf("A video with %f pixels per frame has ", _pixelsPerFrame);
  printf("%f bits per frame\n", _bitsPerFrame);

  //bit rate
  
  /* Commented these lines out as I'm testing the internal
  * logic with known values, first
  * printf("Enter the frame rate in frames per second");
  * scanf("%f", &_frameRate);
  */
  _bitRate = _bitsPerFrame * _frameRate;
  _bitRate = (_bitRate/1024)/1024;
  printf("A video with %f frames per second has ", _frameRate);
  printf("a bit rate of %f bits per second\n", _bitRate);
  
  //video size
  
  /* Commented these lines out as I'm testing the internal
  * logic with known values, first
  * printf("Enter the length for the video in seconds: ");
  * scanf("%f", &_length);
  */
  _videoSize = _bitRate * _length;
  _videoSize = (_videoSize/1024)/1024;
  printf("The video size is %f (in MBITS per second), ", _videoSize);
  printf("which is %f in bytes per second", _videoSize/8);
  return 0;
}