Huahui Wu, Mark Claypool, and Robert Kinicki,
The repeated pattern of I, P and B frames in an MPEG stream is known as the Group of Pictures (GOP). Current GOP choices are made using intuition and informal guidelines without the support of theoretical or practical evidence. This paper studies the impact of the choice of GOP by evaluating the effects of GOP on both static MPEG videos and MPEG videos streaming over a lossy network. The static analysis involves encoding raw video images into MPEG files with various GOP patterns to compare and contrast static properties such as the frame size, file size and quality. The streaming analysis varies the GOP length and pattern to study the impact of GOP on a model of the streaming bitrate and playable frame rate. The results consistently suggest two guidelines: 1) the number of B frames between two reference frames should be close to 2, except when limited to less than 2 by time constraints; 2) the number of P frames should be 5 or fewer as there is little performance gain in setting the number of P frames in the GOP larger than 5.
Huahui Wu, Mark Claypool and Robert Kinicki. Adjusting Forward Error Correction with Temporal Scaling for TCP-Friendly Streaming MPEG, ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP), Volume 1, Number 4, November 2005. Online at: http://www.cs.wpi.edu/~claypool/papers/adaptive-fec-tomccap/
Huahui Wu, Mark Claypool, and Robert Kinicki. Adjusting Forward Error Correction with Quality Scaling for Streaming MPEG, In Proceedings of the 15th ACM International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV), Stevenson, Washington, USA, June 2005. Online at: http://www.cs.wpi.edu/~claypool/papers/adaptive-fec-qual/
Huahui Wu, Mark Claypool, and Robert Kinicki. A Model for MPEG with Forward Error Correction and TCP-Friendly Bandwidth, In Proceedings of Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV), Monterey, California, USA, June 2003. Online at: http://www.cs.wpi.edu/~claypool/papers/adapt-mpeg-fec/
This material is based upon work supported by the National Science Foundation under Grant Number CNS-0423362. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).