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Audio For PBS BROADCAST

Proper audio-video synchronization is crucial for broadcast quality. This workshop from WGBH Public Television highlights common lip sync errors and their solutions across various scenarios. From audio drifting in different broadcasts to alignment issues at multiple points, we explore how to maintain a cohesive viewing experience. Key production tips include testing equipment, aligning sync at every step, and adhering to loudness standards like ATSC A85. Understanding these elements can significantly enhance broadcast quality and viewer satisfaction.

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Audio For PBS BROADCAST

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  1. Audio For PBS BROADCAST

  2. Lip Sync

  3. Errors Can Hide Below Threshold WGBH Public Television Quality Workshop • Scenario #1 • Show: -1 frame, looks OK • Station: -1 frame, looks OK • Broadcast Show: -2 frames, looks bad • Solution: All sync must becorrect (not just look it)

  4. Errors Can Cancel WGBH Public Television Quality Workshop • Scenario #2 • Show: -3 frames • Station: +3 frames • Broadcast Show: 0 frames, looks good • But two wrongs don’t make a right! • Good shows will look bad on this station! • Solution: All sync must becorrect

  5. Errors Can Drift WGBH Public Television Quality Workshop • Scenario #3 • Broadcast Now: Good • Broadcast Later: Bad • Solution: Be Careful! Change Channels! • Millions of commercial and consumer MPEG decoders drift!

  6. Error Perception Can Drift WGBH Public Television Quality Workshop • Scenario #4 • Sync Now: looks good • Same Sync Later: looks bad • Solution: Patience • Need tight shots of people talking • Some people talk out of sync! • Stare at sync long enough, you will start seeing things!

  7. Production Tips WGBH Public Television Quality Workshop • Delay audio with every video delay • Framesyncs • Switcher effects • LCD & Plasma Displays! • Don’t trust your ears • TEST!

  8. Station Tips WGBH Public Television Quality Workshop • Align sync at every point • Framesyncs & processors • MPEG & ATSC encoder settings • Surprises • Don’t trust your ears • TEST!

  9. Test Tools WGBH Public Television Quality Workshop • Edit Suites and QC Stations • syncheck.com • TV Stations • ID with 1 frame dot and beep, then non-linear editor • Normal programming with Miranda or Evertz solutions

  10. Consumer Tips WGBH Public Television Quality Workshop • LCD & Plasma TV's • Internal decoder should be OK • Separate decoder & audio systems require offset! • MPEG decoders • Try changing channels

  11. TV Loudness

  12. Industry Progress • Early Confusion • Subsequent Conflict & Loudness Wars • Recent Consensus: ATSC A85! • www.atsc.org/cms/standards/a_85-2009.pdf WGBH Public Television Quality Workshop

  13. Production Tips WGBH Public Television Quality Workshop • Buy an LKFS meter (BS.1770) • Your mix engineers will like it! • No money? • Dialog peaks at -10 dBFS works pretty well • Produce content to -24 LKFS • Average over entire show, ± 2 dB • Dramatic moments can still be ±10 dB!

  14. Station Tips WGBH Public Television Quality Workshop Set plant for unity gain Set encoder dialnorm to -24 Get an LKFS meter (BS.1770) Measure day-long compliance with -24 LKFS Apply processing if needed Compare local stations and share

  15. Tolerance

  16. 5.1 Surround

  17. 5.1 Surround • PBS Submission Requirement • Effective March 2011! • Up-mix OR actual 5.1 production • Requires Dolby E • Caution • Calibrate your LFE monitoring per ATSC A85 • Insure downmix is compatible • Most stations cannot afford to broadcast 5.1 WGBH Public Television Quality Workshop

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