The command output displays media stream information for the conference. The VP9850, working in Integrated Access Unit (IAU) mode, acts as a conference participant that receives multiple video streams, decodes them, creates a single composite video (continuous presence), and re-encodes it as a new stream sent back to the conference.

In the provided log, the streams from Site (16), Site (17), and Site (18) are the inputs to the IAU. The IAU itself is participating as another site, in this case, Site (19). The stream generated by the IAU will therefore have a source ID (srcId) of 19. The log shows only one video stream with srcId: 19, which has the stream number (strmLabel) 2710124429803.

A. This is the original video stream from Site (16), which is an input to the IAU, not its composite output.

B. This is the original video stream from Site (17), which is an input to the IAU, not its composite output.

C. This is the original video stream from Site (18), which is an input to the IAU, not its composite output.

1. Huawei CloudMCU Product Documentation - Command Reference. The documentation for the conf get strmInfo command specifies that the srcId field indicates the site ID of the media stream's source. This confirms that the stream with strmLabel 2710124429803 originates from the participant with site ID 19.

2. Huawei VP98 Series Universal Transcoding MCU Administrator Guide

Section: "IAU Mode". This guide details that when a VP98 series MCU operates in IAU mode

it joins a conference as a gateway participant. It receives multiple video streams

composes them into a single continuous presence layout

and sends this composite video stream back to the main conference. This supports the conclusion that the IAU (Site 19) generates a new

single stream from the multiple inputs.

3. Huawei HCIP-Video Conference V4.0 Training Material

Module: "MCU Advanced Features". The courseware explains the interaction between an SFU (like CloudMCU) and an IAU. It clarifies that the IAU is treated as a standard endpoint by the SFU

and the composite stream it generates is identified by the IAU's own site ID in the conference's stream table.