What is in a JPEG / JPG file?
Ever open a jpg file with an editor like notepad and wonder what all the characters are? How
does jpeg represent a picture without using so much space?
First of all, how big should a picture file be? or a video for that matter?
say your screen has 1000 rows of dots (pixels), and each row 1000 dots, so a picture consists of 1 million dots.
Each dot is some mixture of red, green, and blue, and may have a 'transparency' set as well.
so, use 1 byte to say how much red, 1 byte to say how much green, 1 byte each for blue and transparency, and you
end up with 4 bytes per dot, and a million dots so about
4 million bytes (characters) for one picture.
30 pictures for one second of video == 120 megabytes for 1 second of video
60 seconds in a minute == 120,000,000 * 60 = about 7.2 gigabytes for one minute of video
150 minutes in a movie == 7.2 gig * 150 = something like:
1 terabyte (1000 gigabytes) for one video
If they were all that big, we wouldn't have our i-devices, or much of any of our current digital world 'cause it
would take too long to send all those bytes to your gadget. jpeg is what shrinks it all and makes it possible.
does jpeg represent a picture without using so much space?
First of all, how big should a picture file be? or a video for that matter?
say your screen has 1000 rows of dots (pixels), and each row 1000 dots, so a picture consists of 1 million dots.
Each dot is some mixture of red, green, and blue, and may have a 'transparency' set as well.
so, use 1 byte to say how much red, 1 byte to say how much green, 1 byte each for blue and transparency, and you
end up with 4 bytes per dot, and a million dots so about
4 million bytes (characters) for one picture.
30 pictures for one second of video == 120 megabytes for 1 second of video
60 seconds in a minute == 120,000,000 * 60 = about 7.2 gigabytes for one minute of video
150 minutes in a movie == 7.2 gig * 150 = something like:
1 terabyte (1000 gigabytes) for one video
If they were all that big, we wouldn't have our i-devices, or much of any of our current digital world 'cause it
would take too long to send all those bytes to your gadget. jpeg is what shrinks it all and makes it possible.