JVET-AO0123 AHG18: Standalone network simulation application on top of ULL software [K. Malyshev, I. Gribushin, V. Khamidullin, M. Sychev, S. Ikonin, E. Alshina (Huawei)]

This document proposes the software modifications on top of AHG18 simulation software allowing to use network simulation as standalone application separated from encoding and decoding process. The standalone application, similarly to JVET-AK0057, parses Annex B format bitstream, and provides a flexibility for testing of various video coding solutions under desired network scenario using pre-encoded uncorrupted bitstreams, and is applicable for broadcasting scenario with no feedback. The proposed modifications keep the network model behaviour same as described in CTC document JVET-AN2039 and implemented in JVET-AO0047, providing the capability of configuring network transmission priorities using configuration file additionally. Option to link network model with encoding application is also possible, which makes possible to test unicast scenario using VTM based software.

Feedback to encoder is implemented in a way that the jitter buffer could inform the encoder about the successful transmission (would require modification of current encoder app).

In current implementation, the network app interprets NAL units as packets, and also gets the priority information from the NAL unit headers (NAL unit type, layer ID to be prioritized can be specified by confif file).

It was commented that for the purpose of using FEC (or other types of redundancy), one option might be to employ unspecified NAL units.

The implementation of feedback mechanism such that those could easily be used by any encoder app seems to require further study. For this, a first step would be to implement the feedback mechanism in the encoder app of JVET-AO0047 such that it can be used with the separated network app.