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Version: 6.1

Application guidance for subgroup API

This page provides guidelines for using the subgroup API. When implementing an application that uses the subgroup API, keep in mind the following:

  1. Only subgroup members can send media (audio, video, and screen share) to the subgroup.
    • Participants who have not subscribed to the subgroup cannot send media to the subgroup.
  2. Only subgroup members can receive media (audio, video, and screen share) from the subgroup.
    • Participants who have not subscribed to the subgroup cannot receive media from the subgroup.
  3. Subgroup name size must be less than 16 bytes including the NULL character.
  4. Subgroup names must be unique.
    • LINE Planet Cloud uses subgroup names to distinguish each subgroup.
    • If participants use the same subgroup name as an argument when calling the SubscribeSubgroup() method, they are subscribed to the same subgroup.
  5. Subscribing to a subgroup fails if any of the subgroup attributes are different.
    • Subgroup attributes are set through the SubscribeSubgroup() method, which accepts parameters for "peerUpdate", "videoUpdate", and "dataSession".
    • Subgroup members belonging to the same subgroup must use the same values for the parameters above.
    • If a participant tries to subscribe with different subgroup attribute values, the subscription fails with PLNK_SUBGRP_SUBS_FAIL_REASON_WRONG_ATTR of ESubgroupSubscribeFailReason.
    • Do not use combination of attributes where "peerUpdate" is NONE and "dataSession" is true. This subgroup attribute combination is not supported, and causes the subscription to fail with PLNK_SUBGRP_SUBS_FAIL_REASON_WRONG_ATTR of ESubgroupSubscribeFailReason.
  6. Subgroup media is independent of each other.
    • Applications can send audio and video to different subgroups at the same time.
  7. The number of subgroups is limited.
    • Creating subgroups consumes a lot of resources in LINE Planet Cloud.
    • The maximum number of subgroups per group call is 30.
    • If the maximum number of subgroups has already been reached, subsequent subscriptions fail with PLNK_SUBGRP_SUBS_FAIL_REASON_OVER_MAX_SUBGRP_CNT of ESubgroupSubscribeFailReason.
  8. You can determine the subgroup from which the media is coming as follows.
    • Audio: PlanetKit provides the currently active speaker's audio volume level along with the user ID and subgroup name.
    • Video: Peer::GetCurrentVideoSubgroupName() returns the subgroup name.
    • Screen share: Peer::GetCurrentScreenShareSubgroupName() returns the subgroup name.
  9. Before unsubscribing from a subgroup, transmission of all media (audio, video, and screen share) to the subgroup must be stopped.

You can find more information in Subgroup basic concepts.