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Video Media

Video Media. Department of Computer Education KMUTNB. Video Media. Video features in a range of Multimedia application. Entertainment Broadcast television and VCR/DVD recordings Interpersonal Video telephony and videoconferencing Interactive Windows containing short video clips.

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Video Media

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  1. Video Media Department of Computer Education KMUTNB

  2. Video Media Video features in a range of Multimedia application • Entertainment • Broadcast television and VCR/DVD recordings • Interpersonal • Video telephony and videoconferencing • Interactive • Windows containing short video clips Multimedia

  3. Video Media Broadcast Television • 525 Lines • NTSC American standard • 60 Fields / second • 30 Frames / second • 625 Lines • PAL European standard/CCIR/SECAM • 50 Fields / second • 25 Frames / second Multimedia

  4. Video Media 1 2 3 4 5 6 720 pixel 720 Sample 1 2 3 4 5 6 Voltage Time Scanning illustrated Multimedia

  5. Video Media Type of Scanning • Progressive = every scan line done in turn. • Interlaced = every other scan line done. • Creates two fields: odd field and even field. • NTSC: 262.5 lines per field at 60 fields per sec. • PAL: 312.5 lines per field at 50 fields per sec. • Fields are separated in time. Multimedia

  6. Video Media 1 TV Frame = 2 Field interlaced scan 1 Computer Frame Progressive scan Computer & TV Multimedia

  7. Video Media Computer & TV Computer ……. ….. 1 Frame Multimedia 1 2 3 4 5 6 7 .. ….. 625 Television ……. ….. ……. 1 Frame 1 3 5 7 .. ….. 625 2 4 6 8 …… 624 312.5 Odd Field 312.5 Even Field

  8. Video Media Video capture with both field Television Computer 1 Computer 2 1 2 3 4 5 6 7 .. ….. 1 2 3 4 5 6 7 .. ….. 312.5 Odd Field Multimedia ……. ….. 1 3 5 7 .. ….. 625 2 4 6 8 …… ……. ….. ……. ….. ……. 312.5 Even Field 625 624 624

  9. Video Media Video capture with one field Television Computer 1 MPEG 1 ( VCD) 312.5 Odd Field Multimedia 1 2 3 4 5 6 7 .. ..312 ……. ….. …. 1 3 5 7 .. ….. 625 2 4 6 8 …… Discard ……. From Interlaced to Progressive system discard resolution in half 312.5 Even Field 624

  10. Video Media Scanning Sequence in TV Multimedia Interlaced scanning principles

  11. Video Media Scanning Sequence in TV Multimedia 525-line systems : 262.5 each field, 240 visible 625-line systems : 312.5 each field, 288 visible

  12. Safe Frame To TV From Camera View Finder To Digital File

  13. Video Media Broadcast Television • Video resolution and quality Multimedia

  14. Video Media 3 Main Properties of a Color • Hue:The actual color of the source, each color has a different frequency/wavelength and eye determines the color from this. • Saturation:The strength of vividness of the color, a pastel color has a lower level of saturation than a color such as red. • Brightness :The amount of energy that stimulates the eye and varies on a gray scale from black (lowest) Through to white(highest) Multimedia

  15. Video Media Luminance & Chrominance • Luminance :is used to refer to the brightness of a source, and the hue and saturation • Chrominance:is used to refer to the color characteristics. Multimedia

  16. Video Media Luminance Component Signal Chrominance TV Color Signals Traditional monochrome TV White --> Black Multimedia Magnitude of the 3 electrical signals that energize the R,G,B Phosphors 0.299R + 0.587G + 0.114B

  17. Video Media Composite Video Signals Ys = 0.299 Rs + 0.587 Gs + 0.114 Bs Cr = Rs - Ys Cb = Bs - Ys Ys is amplitude of luminance signal Rs, Gs, Bs is magnitude of 3 color component signals Multimedia

  18. Video Media Cr Rs - + R G B Ys monochrome + - Gs Cb - + Bs Composite Video Signal Composite Video Signals Multimedia

  19. Video Media Chrominance components From Ys, Cr, Cb PAL : Y = 0.299 R + 0.587 G + 0.114 B U = 0.493 (B - Y) V = 0.877 (R - Y) NTSC : Y = 0.299 R + 0.587 G + 0.114 B I = 0.74 (R-Y) - 0.27(B-Y) Q = 0.48 (R-Y) + 0.41(B-Y) Multimedia

  20. Video Media Signal bandwidth Multimedia Baseband spectrum of color television signals in NTSC system NTSC : Y = 4.2 MHz I = 2 MHz Q = 1 MHz

  21. Video Media Signal bandwidth Multimedia Baseband spectrum of color television signals in PAL system PAL : Y = 5.5 MHz U = 3 MHz V = 3 MHz

  22. Multimedia Summary Digital Video Frames • Almost always progressive • 3 planes of pixel values (Y, U, and V) • Pixel depth • Geometry of each plane: width x height • Chrominance is generally subsampled. Multimedia

  23. Video Media Digital video • The visual perception of the eye have less sensitive for color than luminance • This means that 2 chrominance signals can tolerate a reduced resolution relative to that used for the luminance signal • Saving in terms of resulting bit rate and transmission bandwidth Multimedia

  24. Video Media Digital video standard • International Telecommunications Union Radiocommunications Branch (ITU-R) • Formerly known as the Consultative Committee for International Radiocommunications (CCIR) Recommendation CCIR-601 Multimedia

  25. Video Media CCIR-601 • Standard established for digitizing NTSC and PAL signals Digital Analog CCIR-601 Multimedia Component Counterpart Recommendation Height Lines NTSC: 480 PAL: 576 Width Continuous Sample at 13.5 MHz voltage changes Results in 702 pixels along scan line. Recommended 720 Pixel depth Voltage range. Gamma- corrected 8-bit sample. Chrominance Bandwidth 4:2:2, 4:2:0, 4:1:1 subsampling differences

  26. Video Media Video Color Storing The visual perception of the eye have less sensitive for color than luminance Cb Cb Multimedia Cr Cr Y Y 1,1 2,1 3,1 4,1 1,1 2,1 3,1 4,1 1,2 2,2 3,2 4,2 1,2 2,2 3,2 4,2 1,3 2,3 3,3 4,3 1,3 2,3 3,3 4,3 1,4 2,4 3,4 4,4 1,4 2,4 3,4 4,4 From Source Storing method

  27. Video Media Video Color Playback Cr,Cb Cr,Cb Cb Cb 3,1 3,1 1,1 1,1 Multimedia Cr Cr 1,1 1,1 3,1 3,1 3,2 Y Y 3,2 1,1 2,1 3,1 4,1 1,1 2,1 3,1 4,1 3,3 3,3 1,2 2,2 3,2 4,2 1,2 2,2 3,2 4,2 3,4 3,4 1,3 2,3 3,3 4,3 1,3 2,3 3,3 4,3 1,4 2,4 3,4 4,4 1,4 2,4 3,4 4,4 Playback process

  28. Video Media Video Digitization Formats • 4:2:2 means 2:1 horizontal downsampling, no vertical downsampling. (Think 4 Y samples for every 2 Cb and 2 Cr samples in a scanline.) • 4:1:1 ought to mean 4:1 horizontal downsampling, no vertical.(Think 4 Y samples for every 1 Cb and 1 Cr samples in a scanline.)It is often misused to mean the same as 4:2:0 . • 4:2:0 means 2:1 horizontal and 2:1 vertical downsampling.(Think 4 Y samples for every Cb and Cr samples in a scanline.) Multimedia

  29. Video Media 4:2:2 • Use in television Studio • For every 4 luminance samples, take 2 chrominance samples from odd lines and 2 from even lines. • Chrom. planes just as tall, half as wide. • JPEG does this. Multimedia

  30. Video Media 4:2:2 Multimedia Sample positions with 4:2:2 digitization format

  31. Video Media 4:2:2 Every 4 pixel Cb Cb Cr Cr Y Y Multimedia Keep 2 odd 1,1 2,1 3,1 4,1 1,1 2,1 3,1 4,1 Keep 2 even 1,2 2,2 3,2 4,2 1,2 2,2 3,2 4,2 1,3 2,3 3,3 4,3 1,3 2,3 3,3 4,3 1,4 2,4 3,4 4,4 1,4 2,4 3,4 4,4 From Source Storing method Storage size Y+Cr+Cb Storage size Y+0.5Cr+0.5Cb Sample positions with 4:2:2 digitization format

  32. Video Media 4:2:0 • Used in Digital Video broadcast application • 2 chrominance samples for every 4 luminance samples, odd lines only. • Chrominance halved in both directions. • MPEG generally does this. Multimedia

  33. Video Media 4:2:0 Multimedia Sample positions with 4:2:0 digitization format

  34. Video Media 4:2:0 Every 4 pixel Cb Cb Cr Cr Y Y Multimedia Keep 2 odd 1,1 2,1 3,1 4,1 1,1 2,1 3,1 4,1 Keep 0 even 1,2 2,2 3,2 4,2 1,2 2,2 3,2 4,2 1,3 2,3 3,3 4,3 1,3 2,3 3,3 4,3 1,4 2,4 3,4 4,4 1,4 2,4 3,4 4,4 From Source Storing method Storage size Y+Cr+Cb Storage size Y+0.25Cr+0.25Cb Sample positions with 4:2:0 digitization format

  35. Video Media 4:2:0 Cb Cb Cr Cr Multimedia Play Y Y 1,1 2,1 1,1 2,1 1,2 2,2 1,2 2,2 4:2:0 playback process

  36. Video Media 4:2:0 • To avoid flicker effect with the chrominance signal • the receiver uses the same chrominance value from the sampled lines for the misslines • Large-screen flicker effects are often reduced by • storing the incoming digitized signals of each field in a memory buffer • Double the normal rate 100/120 Hz then used with the stored set of signals used for the 2 field Multimedia

  37. Video Media HDTV • High-Definition Television • Older 4/3 aspect ratio 1440 x 1152 pixels • newer 16/9 aspect ratio 1920 x 1152 pixels • 1080 visible lines per frame • 4:2:2 digitization for studio application • Frame rate 50/60 Hz • 4:2:0 digitization for broadcast application • Frame rate 25/30 Hz Multimedia

  38. Video Media SIF • Source Intermediate Format • Used in Video Cassette Recorders (VCR) • Used Half spatial resolution in both horizontal and vertical in 4:2:0 format • Frame rate 30 Hz for 525 line, 25 Hz for 625 line • Progressive (non interlaced) scanning • The receiver estimated by interpolating between each pair of value missing line Multimedia

  39. Video Media SIF and CIF Multimedia Sample positions for SIF and CIF

  40. Video Media SIF and CIF Cb Cb Cr Cr 2,2 Y Y Multimedia 2,2 1,1 2,1 3,1 4,1 1,1 3,1 1,2 2,2 3,2 4,2 1,3 2,3 3,3 4,3 1,3 3,3 1,4 2,4 3,4 4,4 From Source Storing method Storage size Y+Cr+Cb Storage size 0.25Y+0.0625Cr+0.0625Cb Sample positions with 4:2:0 digitization format

  41. Video Media Cb All 2,2 Cb Cr All 2,2 Cr 2,2 Y Y 2,2 1,1 1,1 3,1 3,1 1,1 3,1 1,1 1,1 3,1 3,1 1,3 1,3 3,3 3,3 1,3 3,3 1,3 1,3 3,3 3,3 Playback Storing method SIF and CIF Multimedia Sample positions with 4:2:0 digitization format

  42. Video Media Cb Cr 2,2 Y Y 2,2 1,1 3,1 1,1 3,1 1,3 3,3 1,3 3,3 Capture to Computer From Video Tape or Home use Quality Signal When Capture from Video Tape Multimedia Video Tape Video Clip 360x288 360x288 Sample positions with 4:2:0 digitization format

  43. Video Media CIF • Common Intermediate Format • Defined for use in Videoconferencing applications • Typical bit rate used is a single 64 kbps ISDN channel • Can multiple channel for high bit rate 4CIF: Y= 720 x 576 Cb = Cr = 360 x 288 16CIF: Y= 1440 x 1152 Cb = Cr = 720 x 576 Multimedia

  44. Video Media CIF 360x288 64 kbps CIF 64 kbps 64 kbps CIF 64 kbps Multimedia 360x288 720x576 256 kbps CIF CIF CIF CIF 256 kbps CIF CIF CIF CIF 720x576 In Videoconference Application

  45. Video Media Common Digital Video Sizes • CCIR-601 720x480 4:2:2, 4:2:0 • SIF 360x240 4:2:0 • CIF 360x288 4:2:0 • 4:3 HDTV 1440x1152 4:2:2, 4:2:0 • 9:16 HDTV 1920x1152 4:2:2, 4:2:0 • 4CIF, 16CIF, QCIF Multimedia

  46. Video Media PC video digitization formats Multimedia

  47. Video Media Multimedia Communication Standards • H.320 Video Teleconferencing Standard • Visual Telephone System over N-ISDN • H.324 • low bit rate multimedia communication terminal for PSTN and Mobile Radio • H.321, H.310 • high resolution broadband audiovisual communication systems via B-ISDN • H.322, H.323 • narrowband visual telephone services on LAN Multimedia

  48. Video Media Referrence • Multimedia communication Application, Networks, protocols and standards; fred halsall. Chapter 2 Multimedia information representation page 96-113; ISBN 0201398184 • http://www.sce.carleton.ca/courses/96502 • http://www.crs4.it/~luigi/MPEG/ccir601.html • http://www.broadcastengineering.com/archives/0198/199801be15.html • http://www.cs.unc.edu/~kmp/classes/sp01/comp249 Multimedia

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