Page History

@startuml

autonumber

box "Container" #LightGreen
participant Cobalt
participant Starboard
participant GStreamer_client
participant rialtoClient
end box

box "Platform" #LightBlue
participant rialtoServer
participant GStreamer_server
end box

== Initialisation - register for callbacks ==

opt Video source attached
rialtoServer       ->  GStreamer_server:     g_signal_connect(video_decoder, getVideoUnderflowSignalName_soc(), video_underflow_cb, user_data);
GStreamer_server   --> rialtoServer:         video_handler_id
end

opt Audio source attached
rialtoServer       ->  GStreamer_server:     g_signal_connect(audio_decoder, getAudioUnderflowSignalName_soc(), audio_underflow_cb, user_data);
GStreamer_server   --> rialtoServer:         audio_handler_id
end


== Termination - unregister for callbacks ==

opt Video source removed
rialtoServer       ->  GStreamer_server:     g_signal_handler_disconnect(video_decoder, video_handler_id);
GStreamer_server   --> rialtoServer:
end

opt Audio source removed
rialtoServer       -> GStreamer_server:     g_signal_handler_disconnect(audio_decoder, audio_handler_id);
GStreamer_server   --> rialtoServer:
end


== Underflow ==

opt Data starvation in server AV pipeline
GStreamer_server   -/  rialtoServer:         video_underflow_cb() or audio_underflow_cb()
note across
underflow_enabled: Underflow is enabled when we're in playing state and source is attached.
underflow_cancelled: Underflow may be cancelled when haveData is called between notification from GStreamer and Underflow task handling.
end note
opt underflow_enabled && !underflow_cancelled
rialtoServer       -/  rialtoClient:         notifyBufferUnderflow(source_id)
rialtoClient       -/  GStreamer_client:     notifyBufferUnderflow(source_id)
GStreamer_client   -/  Starboard:            emit video_underflow_cb() or audio_underflow_cb()

note over Starboard, GStreamer_client
Starboard does not have any support for underflow
so the event can be ignored for this integration.
end note

end

note across
There will be one re more pending need data requests at this point which if serviced will allow playback to resume
end note

end

@enduml