Media Traffic Generator (Discussion)

23d1ad8982616babb4d5b60470eea8a4?s=47 Varun Singh
November 03, 2013

Media Traffic Generator (Discussion)

RMCAT WG Discsussion
03 November, Vancouver


Varun Singh

November 03, 2013


  1. Media Traffic Generator IETF 88, Vancouver 3rd November 2013 Varun

    Singh, Colin Perkins
  2. Agenda •  Note well applies! •  Note-takers? •  Traffic model/generators

    –  Variability in video –  Responsiveness to new target rates •  Congestion control design related 2 of 7
  3. RMCAT CC Evaluation •  No Traffic Generator –  Application generates

    rates estimated by the congestion controller. •  Media Traffic Generator –  Application generates rates as close to the estimated rate. –  Can we make an abstract model of a modern codec? •  Real sequences –  Applications generates rates based on type of video sequence (codec) and estimated rate by the congestion controller. 3 of 7
  4. Modeling: Variability •  Variation in media bit rate for a

    given target bit rate? –  Effects of I-Frame? •  How to model motion? –  capturing high motion leads to higher than target bit rate, but by how much? •  Any limits on media rates? –  Minimum video rate? –  Maximum video rate? 4 of 7
  5. Modeling: Responsiveness How quickly can the codec generate a • 

    lower bit rate? –  From the next frame? –  At the end of a GoP (I-Frame)? –  if not immediately, what bitrates (and duration) will it generate before meeting the target bitrate. •  higher bit rate? 5 of 7
  6. Who is in Control? •  Application control vs Congestion control

    –  Video and audio frame rate –  Video resolution •  What is relationship between NACK/ACKs for reliability and congestion control? •  What is the relationship of FEC for reliability and rate probing? –  Probing by reducing/adding redundancy (FEC) –  is something like this done? Does this makes sense at all? 6 of 7
  7. Congestion Cues •  Path Chirp: probe for bandwidth by sending

    additional data packets in a certain pattern. –  would something link this help? •  Delay and loss: What about other congestion cues? –  e.g., Decoding rate/goodput, application decode error rate, ECN, PCN, … 7 of 7