2. Lecture 8: Video Intro to IT COSC1078 Introduction to Information Technology Lecture 8 Video James Harland james.harland@rmit.edu.au

3. Lecture 8: VideoIntro to IT Introduction to IT 1-3 Introduction, Images, Audio 4 Video 5 Computer Fundamentals Assignment 1, WebLearn Test 1 Tuesday March 30 th, Wednesday March 31 st (no classes Thursday 1 st April, Tuesday 6 th April, Wednesday 7 th April) 6 Computer Fundamentals Tuesday April 13 th, Wednesday April 14th 7 Computer Fundamentals 8 Operating Systems WebLearn Test 1 9 Operating Systems Assignment 2 10 Internet 11 Internet Security WebLearn Test 3 12 Future of ITAssignment 3, Peer and Self Assessment

4. Lecture 8: VideoIntro to IT Overview  Questions?  WebLearn Test 1  Assignment 1  Video  Questions?

5. Lecture 8: VideoIntro to IT Web Test 1  Now Week 5, not week 4 (so not this week)  Quizzes (practice tests) up later this week  Content will be on weeks 2-4 Images Audio Video

6. Lecture 8: VideoIntro to IT Assignment 1  Due date is 9.00am on Monday 12 th April (1 st day of Week 6)  Forget whatever this bloke said yesterday  Can submit now if you wish …  Sensible to submit something soon

7. Lecture 8: VideoIntro to IT Introduction Who is this bloke?

8. Lecture 8: VideoIntro to IT Overview 01010100001010101010100110100010101001101001010010 100011100010101010100101111001001010…

9. Lecture 8: VideoIntro to IT Time codes and all that … Time for videos HH:MM:SS:FF HH hours MM minutes SS seconds FF frames Often 30 frames per second (nice and neat!) NTSC colour uses 29.97 frames per second (!!) This means there are two timecode systems ….

10. Lecture 8: VideoIntro to IT Non-drop-frame timecode HH:MM:SS:FF Behaves as expected FramesMinutes (30 fps) Non-drop-frame timecode 17990.999400:00:59:29 1800100:01:00:00 179819.98900:09:59:11 179829.99000:09:59:12 180001000:10:00:00

11. Lecture 8: VideoIntro to IT Drop-frame timecode HH;MM;SS;FF Seems bizarre! Skips time codes 00;01;00;00 00;01;00;01 00;02;00;00 00;02;00;01 00;03;00;00 00;03;00;01 …. 00;09;00;00 00;09;00;01 Skips 18 codes per 10 minutes 00;00;59;29 00;01;00;02 … 00;01;59;29 00;02;00;02 … 00;09;59;29 00;10;00;00

12. Lecture 8: VideoIntro to IT Drop-frame timecode FramesMinutes (29.97fps) Minutes (30 fps) Drop-frame timecode Non-drop- frame timecode 17991.00040.999400;00;59;2900:00:59:29 18001.001100;01;00;0200:01:00:00 179819.9999.98900:09:59:2900:09:59:11 17982109.99000;10;00;0000:09:59:12 1800010.0101000;10;00;1800:10:00:00

13. Lecture 8: VideoIntro to IT Video file size Video files can be big! How much space is need for 1 second of HDTV? 1440 x 1080 pixels 24-bit colour 30 fps Stereo (2 audio channels) Audio sampling 48 kHz and 16-bit depth

14. Lecture 8: VideoIntro to IT Video file size Audio: 48,000 samples/s x 1s x 16 bits/sample x 2 = 1,536,000 bits = 192,000 byes ≈ 188 KB Video: 1440 x 1080 pixels/frame x 24 bits/pixel = 37,324,800 bits/frame 37,324,800 bits/frame x 30 fps x 1s = 1,119,744,000 bits = 139,968,000 bytes = 133 MB (!!) This takes 133MB per second! Need to compress

15. Lecture 8: VideoIntro to IT Colour Sampling Eye more sensitive to brightness than colour YUV model: Y luminance U,V chrominance 3 samples per pixel, so 12 samples per 4 pixels NameYUVSizeSaving 4:4:44Y, 4U, 4V120% 4:2:24Y, 2U, 2V833% 4:2:04Y, 2 (U or V)650% YUV YYYY YYYY UV UU

16. Lecture 8: VideoIntro to IT File size and Data rate Overall file size is one thing 133MB x 60 minutes/second x 60 minutes/hour x x 2 hours = 957,600 MB ≈ 935 GB (!!) Still need to be able to extract data at 133MB per second, even for only 1 second … 48x CD is about 7MB per second..

17. Lecture 8: VideoIntro to IT Compressing Video Files  Lower frame size  Lower frame rate  Lower picture quality (ie data rate)  Lower colour depth (not often done …)  Lower audio quality (not much effect)  Compression methods (lossy vs lossless) compressor/decompressor or codec

18. Lecture 8: VideoIntro to IT Assignment 1  Use GIMP (or a similar tool) to perform some manipulations on an image  Address two issues in relation to this  Lab classes 2 and 3 based around GIMP  Main emphasis is on process, not result!  Is in the Learning Hub  SUBMIT VIA WEBLEARN JUST DO IT!

19. Lecture 8: VideoIntro to IT Assignment 1

20. Lecture 8: VideoIntro to IT Conclusion  Web Test next week (week 5)  Do online quizzes later this week  Keep reading! (book particularly)  Notes for Video in Learning Hub