High Definition Video: Acquisition to Broadcast

2. High Definition Video: Acquisition to Broadcast

3. Overview • Defining the term “High Definition” • Pixel, frame and video formats • Image acquisition • Storage media • Compression • Post production • Transmission and the digital switchover • Reception and “HD Ready” • Home entertainment HD

4. What is HD? • Anything providing more resolution than current standard definition (SD) video. • It is a generic term for “better” • It doesn’t specify how much better.

5. Standard definition • For the UK, a system known as PAL • Broadcast systems comprising 625 lines • 25 frames per second • After signalling and data removed, a frame resolution of 768x576 pixels • Frame aspect of 4:3 (768:576 simplified to it’s lowest common factor)

6. Standard definition SD, 4:3 3 576 4 768

7. Standard definition • 768x576 assumes a square pixel • Pixels don’t have to be square and in SD video, they usually aren’t! • 4:3 PAL uses a pixel aspect of 1.066666:1 • Your TV “stretches” the frame horizontally • Anything that increases the size of a pixel reduces resolution

8. Standard definition Standard definition 3 4

9. Widescreen • A further extension of this kludge • Very un-square pixels • 16:9 broadcasts take the 720x576 frame and stretch it even more horizontally

10. Standard definition Widescreen standard definition 3 9 16 4

11. Standard definition • Uses anamorphic pixels • 4:3 – 1.0666:1 • 16:9 – 1.4222:1 • Results in resolution being lost due to the stretching process

12. High Definition • Two common formats • 720p • 1080i • SD frame: 720 x 576 • 720p frame: 1280 x 720 (2.2 x SD) • 1080i frame: 1920 x 1080 (5 x SD)

13. High Definition 1920x1080i, 16:9 1280x720p, 16:9 SD 720x576, 4:3

14. High Definition(or “what all the fuss is about”) • 1080i provides almost five times the resolution of Standard Definition • Unencumbered by legacy technology • Native 16:9 aspect ratio • True 720p and 1080i are square pixel formats – no resolution-killing scaling when displayed

15. Image Acquisition • Professional: anything with mechanical manual focus • “Prosumer” – Servo-operated focus / fixed lenses that provide similar functionality to pro cameras • Consumer - point-and-shoot cameras that do all of the hard work for you!

16. Professional cameras Unlimited budget ARRI 320D • Can shoot film resolutions • CCD is the same size as a 35mm frame • Needs a huge amount of peripherals • Camera alone starts at £200,000 • Lenses £20,000 upwards

17. Professional cameras

18. Professional cameras Top-end HDC-1500L444 • Native 1080p • Variable frame rates (1 to 60fps) • Still needs lots of peripherals • Camera alone starts at £80,000

19. Professional cameras Mainstream HD HDW-F900R • Native 1080i • Integral HDCAM recorder • More realistic price: £40,000

20. Professional cameras Optical storage PDW-F350 • Native 1080i • Integral ProDisc recorder • £10,000

21. Professional cameras Budget professional JVC GY-HD251E • Native 1080i • Integral 720p HDV recorder • Still uses “proper” lenses • £5000

22. “Prosumer” cameras Canon XHA1 • Native 1080i • Integral 1080i HDV recorder • Internal focus lens • £2200

23. “Prosumer” cameras Sony HVR-V1E • Native 1080i • Integral 1080i HDV recorder • Internal focus lens • £1500

24. Consumer cameras Sony HDR-HC7E • Native 1080i • Integral 1080i HDV recorder • Internal focus lens • £800

25. Consumer cameras Canon HV20 • Native 1080i • Integral 1080i HDV recorder • Internal focus lens • £650

26. Consumer cameras Sanyo DMX-HD1000 • Native 1080i • Uses standard SD flash storage • 4.2 megapixel stills • £450

27. Consumer cameras

28. Image Acquisition • For home use, size and convenience are generally more important than features • “More expensive” doesn’t necessarily mean “better” or “more suited” • The manual functions on pro cameras just get in the way when you’re simply trying to shoot something

29. Lens Image sensor Processing electronics Storage Image Acquisition

30. Image Acquisition

31. Video storage • Tape • Optical disc • Hard drives • Flash memory

32. Video Tape Recorders

33. Video Tape Recorders

34. Video Tape Recorders

35. Video Tape Recorders

36. Principal HD tape formats

37. Tape: pros • Relatively cheap • Universally accepted for interchange • Long shelf life when stored correctly • Long recording durations

38. Tape: cons • Linear by nature • Limited record / playback cycles • No warning during recording of drop-out • Easily damaged if handled carelessly • Easily damaged by deck malfunction • Easily damaged by incorrect storage • Decks can be very expensive to maintain

39. Tape: cons Deck malfunction Incorrect storage

40. Tape: cons • Linear by nature • Limited record / playback cycles • No warning during recording of drop-out • Easily damaged if handled carelessly • Easily damaged by deck malfunction • Easily damaged by incorrect storage • Decks can be very expensive to maintain

41. Tape: cons

42. Video storage: Tape Q:Who won the VHS vs. Beta format war? A: Sony’s Beta! • Betacam SP • Betacam SX • MPEG IMX • Digital Betacam • HDCAM • HDCAM SR

43. Video storage: Tape

44. Video storage: optical disc

45. Optical disc: pros • Robust • High number of read/write cycles • Non-linear: near instant access • Easy ingest to editing systems • Improved workflow • Supports multiple formats (SD & HD)

46. Optical disc: cons • Read/write cycles not as high as expected • Harsh conditions can upset recording • Limited shelf-life – data degrades with time

47. Video storage: hard discs

48. Hard drives: pros • Fast – capable of recording uncompressed • Non-linear – instant access • Capacity – multi-terrabyte • Unlimited read/write cycles • Immediate ingest

49. Hard drives: cons • Not portable • Camera-to-drive interfaces can be costly • Failures often catastrophic • Not practical for long-term storage • Can be noisy

50. Video storage: hard discs