1 / 38

Over-the-Air (OTA) Bit Management

Over-the-Air (OTA) Bit Management. David Felland Milwaukee Public Television. Acquisition and Distribution. New impacts on broadcast transport stream Better coding efficiency in new HD encoders Claims of 10-15% improvement

topper
Download Presentation

Over-the-Air (OTA) Bit Management

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Over-the-Air (OTA) Bit Management • David Felland • Milwaukee Public Television

  2. Acquisition and Distribution New impacts on broadcast transport stream Better coding efficiency in new HD encoders Claims of 10-15% improvement Potential for two 720p HD services in one transport stream – or other services More SD services from which to choose Mobile DTV Fixed and Mobile DTV Data Services

  3. Public television has used its spectrum to serve diverse audiences with more variety in content (“multicasting”) Pluses: greater range of services; potential higher value to individual communities Minuses: locked into audience expectations; stations are forced to balance video quality with service quantity Tradeoffs affect Quality:

  4. Bit Management Some options for broadcasters Reduced horizontal resolution (1440 vs 1920) Noise reduction of both HD and SD Modern statistical multiplexing 720p vs. 1080i X X ☺ ☺

  5. What are stations doing? Surveyed the ETAC 1-3 OTA services Different services plans among all members Focus on HD + national / local SD services

  6. ETAC Members’ OTA Italics = Stat Mux Pool

  7. ETAC Members’ OTA (x4) (x2) (x2) Italics = Stat Mux Pool

  8. ETAC Members’ OTA Italics = Stat Mux Pool

  9. ETAC Members’ OTA (x2) Italics = Stat Mux Pool

  10. ETAC Members’ OTA Italics = Stat Mux Pool

  11. Mobile DTV Bandwidth UsageHow much OTA spectrum is needed? Mobile / Handheld service requirements Multiple modes – e.g., “Half-rate”, “Quarter-rate”, or a variety of “Mixed Modes” Many broadcasters will use Quarter or Mixed Quarter  ~17% payload (83% FEC) Mixed (e.g., ½, ¼, ¼, ¼)  ~ 26% (74% FEC) Half  ~34% payload (66% FEC)

  12. Bandwidth Usage (bits)How much OTA spectrum is needed? Mixed Mode examples (26%): One 500 kbps stream  ~1.92 Mbps Video@400kbps; Audio@64kbps; Data@30kbps Two 500 kbps streams  ~3.85 Mbps Quarter Rate examples (17%): One 500 kbps stream  ~2.94 Mbps Video@400kbps; Audio@64kbps; Data@30kbps Two 500 kbps streams  ~5.88 Mbps

  13. Some Mobile PTV Services Simulcast of Local HD or SD Services Simulcast of National HD or SD Services Stand alone Local Mobile Services National or Local Kids Service “Radio” Services Audio Only – 16 – 48 kbps “Audio with Pictures” – same as Video/Audio

  14. DTV Spectrum Usage:ETAC Member #1 128 kbps • Data/Ancillary • PSIP 150 kbps ~3 Mbps • SD program 19.4 Mb/s DTV Transport Stream ~15 Mbps Stat Mux Pool • HD program

  15. DTV Spectrum Usage:ETAC Member #2 1Mbps+128 kbps • Data/Ancillary • PSIP 250 kbps ~2.5 Mbps • SD program 19.4 Mb/s DTV Transport Stream ~2.5 Mbps • SD program ~12 Mbps Stat Mux Pool • HD program

  16. ETAC Member #1:One Mobile Service (Mixed) ~2 Mbps • Mobile program 128 kbps • Data/Ancillary • PSIP 150 kbps ~2.5 Mbps • SD program 19.4 Mb/s DTV Transport Stream ~13.5 Mbps Stat Mux Pool • HD program

  17. ETAC Member #2:One Mobile Service (Mixed) ~2 Mbps • Mobile program 1Mbps+128 kbps • Data/Ancillary • PSIP 250 kbps 19.4 Mb/s DTV Transport Stream ~2 Mbps • SD program ~2 Mbps • SD program ~11 Mbps Stat Mux Pool • HD program

  18. DTV Spectrum Usage:ETAC Member #14 1Mbps • Data/Ancillary • PSIP 150 kbps ~3 Mbps • SD program 19.4 Mb/s DTV Transport Stream ~3 Mbps • SD program Stat Mux Pool ~10 Mbps • HD program

  19. ETAC Member #14:Multiple Mobile Services (Mixed) ~2 Mbps • Mobile program ~2 Mbps • Mobile program • Radio Services (100k) 1Mbps • Data/Ancillary 19.4 Mb/s DTV Transport Stream • PSIP 250 kbps • SD program ~1.8 Mbps • SD program ~1.8 Mbps Stat Mux Pool ~9.5 Mbps • HD program

  20. Other Stations:Possible Mobile Services (Mixed) ~2 Mbps • Mobile program ~2 Mbps • Mobile program ~2 Mbps • Mobile program • PSIP 250 kbps 19.4 Mb/s DTV Transport Stream • Weather ~2 Mbps ~11 Mbps Stat Mux Pool • HD program

  21. Other Stations:Possible Mobile Services (1/4 rate) ~3 Mbps • Mobile program ~3 Mbps • Mobile program • PSIP 250 kbps 19.4 Mb/s DTV Transport Stream • Weather ~2 Mbps ~11 Mbps Stat Mux Pool • HD program

  22. Other Stations:Possible Mobile Services (Mixed) • Mobile program ~2 Mbps • Mobile program ~2 Mbps • Mobile program ~2 Mbps • Mobile program ~2 Mbps 19.4 Mb/s DTV Transport Stream • Mobile program ~2 Mbps • Mobile program ~2 Mbps • Mobile program ~2 Mbps • PSIP 100 kbps ~4.5 Mbps • SD program

  23. Sorry but No Free Lunch! MPEG very cleverly hides picture errors BUT Errors hidden at one stage can appear downstream Don’t use an extra codec cycle simply because you can Use suitable workflow techniques Don’t over compress master recordings Plot your program performance to the end user Test and understand how to use MPEG tools properly

  24. How does my show look? Examples of original video compared to: 720 progressive at different station presentation rates 1080 interlace at different station presentation rates Producer tech choices drive the viewer experience Downstream network workflow and distribution Local station bandwidth constraints and practices Quality pictures at home require Best Practices upstream

  25. Some Best Practices Use progressive acquisition cameras Use higher frame rates Avoid interlace – Digital TV handles it inefficiently Streamline post production workflow Successive coders will reduce picture quality Assume your show will look worse downstream Prove that the tools you use “do minimal harm”

  26. Observations and Suggestions: Many stations are moving to 720p replacing spatial resolution with improved temporal resolution Significantly reducing picture blocking artifacts Reducing horizontal resolution With an increase in demand for more services public television can improve performance by Dropping interlace and moving to progressive pictures Replacing older HD encoders with the next generation Changing PBS satellite distribution to progressive

  27. Video Examples

  28. Questions?

More Related