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1、A Guide to Standard and High-DefinitionDigital Video MeasurementsD i g i t a l V i d e o M e a s u r e m e n t The Beginning 1Traditional television 1The “New” Digital Television 2Numbers describing an analog world 2Component digital video 2Moving Forward from Analog to Digital 3The RGB component si
2、gnal 3Gamma correction 4Gamma correction is more than correction for CRT response 5Conversion of RGB into luma and color difference 5The Digital Video Interface 7601 sampling 9The parallel digital interface 11The serial digital interface (SDI) 12High-definition video builds on standard definition pr
3、inciples 14Timing and Synchronization 17Analog video timing 17Horizontal timing 18Vertical timing 20Analog high-definition component video parameters 24Digital Studio Scanning Formats 25Segmented frame production formats 25Digital Studio Synchronization and Timing 27Telecine synchronization 30Digita
4、l Audio 31Embedded audio in component digital video 32Extended embedded audio 33Systemizing AES/EBU audio 34Video Measurements 35Monitoring and measuring tools 35Monitoring digital and analog signals 36Assessment of video signal degradation 36Video amplitude 36Signal amplitude 37Frequency response 3
5、9Contents A Guide to Standard and High-Definition Digital Video Measurements A Guide to Standard and High-Definition Digital Video Measurements PrimeriiGroup delay 39Non-linear effects 40Differential gain 41Differential phase 41Timing between video sources 41Intrachannel timing of component signals
6、41Waveform method 41Timing using the Tektronix Lightning display 42Bowtie method 43Operating a Digital Television System 45RGB and color-difference waveforms 45Component gain balance 45The vector display 45The Lightning display 47The Diamond display 48The Arrowhead display 49Digital System Testing 5
7、1Stress testing 51Cable length stress testing 51SDI check field 51CRC error testing 52Jitter testing 52Eye pattern testing 53Conclusion 54Appendix A Color and Colorimetry 55White 56Red, green, and blue components 56Gamut, legal, valid 59Format conversion tables 61Appendix B Television Clock Relation
8、ships 63Appendix C Standard Definition Analog Composite Video Parameters 65Appendix D Reference Standards and Practices for Television 67Appendix E Bibliography 69Appendix F Glossary 71Acknowledgements 79About the authors 79Disclaimer Guide to Standard and High-Definition Digital Video MeasurementsP
9、rimerA Guide to Standard and High-Definition Digital Video Measurements P is tempting to think of digital television as something very scientific andeven complex. But when we view the end result, we find something veryfamiliar; something television engineers have sought since the very begin-ning an
10、experience that just keeps getting better and better qualityvideo and audio conveying the artists performance to the viewing audi-ence. The only thing new in digital television is the way the message getsfrom here to there.Does it really matter how the message travels? The artist and the viewer(and
11、in many countries, the advertiser) probably dont care what path thesignal takes. They can benefit from digital televisions improved perform-ance without knowing the details. Ah, but the science. thats where thefun comes in. Those of us involved in the technical side of television docare; and we do b
12、enefit from the significant advances in television scienceover the past 60+ years and in particular the advances brought about bydigital television over the past 20 years.Program video, digital audio, and associated ancillary data signals togethermake up the digital television signal. In the analog
13、world of television, videoand audio can exist in totally separate paths from source to the home tele-vision receiver. Digital signals may be organized with much more freedom,with video, audio, and other signals working together as a stream of data.All we need to know is how the data is organized to
14、pick out what wewant.Traditional televisionWe can call analog video and analog audio the elements of traditional tele-vision. But it is important to realize we are still trying to accomplish the tra-ditional goals and maybe more. Digital television builds on analog, andour understanding of digital t
15、elevision builds on what we already knowabout analog television. Light into the camera lens and sound into themicrophone, are still analog. Light from the display and sound to your earsare still analog phenomena.We already know that analog video is a “sampling” of light values. Valuesof brightness r
16、epresented by a voltage. And additional information providesthe color of the samples. The samples are synchronized through the trans-mission system to reproduce an image of the original scene on our display.Analog video travels as a “serial” stream of voltage values containing all ofthe “data” necessary to make a picture when the receiver knows what todo with the information. So you can see that by just substituting a fewwords, and by just doing a few things differently to take advantage of what
