ITU-T Recommendations

Amendment 2 to Recommendation ITU-T P.1201 (2012) introduces Appendix III.
Appendix III to ITU-T P.1201 describes a method allowing ITU-T P.1201 to be used for quality predictions of TCP-based, non-adaptive streaming typically referred to as progressive download (PD). The appendix can be used standalone, since it reproduces the required portions of model algorithms from ITU-T P.1201.1 and ITU-T P.1201.2.
Here, the following changes or additions have been applied to the ITU-T P.1201 scope:
– Longer duration source sequences of between 30 s and 60 s compared to 10 s to 16 s long source sequences as in the case of the ITU-T P.1201.1, ITU-T P.1201.2, ITU-T P.1202.1 and ITU-T P.1202.2 models;
– TCP-based transport instead of UDP-based transport;
– Inclusion of longer stalling events as they may occur in case of playout-buffer underrun;
– Inclusion of initial buffering, before the actual playout starts.
It is noted that the model has been developed based on a relatively small subjective test dataset, as compared to the large database used for the ITU-T P.1201.x series model training and validation procedure.
What is not addressed by this model:
– Adaptive streaming;
– Sequences longer than 60 s;
– User-interaction with the player (stop, play, rewind, fast forward, jump to specific part of sequence, etc.).
The goal of this appendix is to provide the market with an initial model capable of estimating quality related with PD-type streaming applications but with a limited scope.
The appendix is targeted to be usable standalone, and therefore the required parts from ITUT P.1201 and the model descriptions in ITU-T P.1201.1 and ITU-T P.1201.2 are provided here for the implementers' convenience.