...

The shared memory buffer shall be split into two regions for each playback session, one for a video stream, and the other for audio (only one concurrent audio track supported, for audio track selection previous audio must be removed first). Each region must be big enough to accommodate the largest possible frame of audio/video data plus associated decryption parameters and metadata. At the end there is also a separate section for webaudio regions (common for all playback sessions). The buffer shall initially be sized to 8Mb per playback session to allow some overhead + 10kB * number of webaudio regions. There can be 0 or more Web Audio regions per Rialto Client.

For apps that can support more than one concurrent playback the shared memory buffer shall be sized accordingly and partitioned into different logical areas for each playback session. The partitions need not necessarily be equally sized, for example if an app supports one UHD and one HD playback the 'HD' partition may be smaller. There can be 0 or more Web Audio regions per Rialto Client.

draw.io Diagram

border	true
diagramName	Shared memory partitioning for multiple playbacks
simpleViewer	false
width	links	auto
tbstyle	top
lbox	true
diagramWidth	1261
revision	2

...

draw.io Diagram

width

border	true
diagramName	Shared memory buffer layout for AV stream
simpleViewer	false
links	auto
tbstyle	top
lbox	true
diagramWidth	791
revision	1

...

draw.io Diagram

border	true
diagramName	Metadata format v1
simpleViewer	false
width	links	auto
tbstyle	top
lbox	true
diagramWidth	431
revision	1

...

draw.io Diagram

border	true

diagramName	Shared memory buffer layout v2
simpleViewer	false
width
links	auto
tbstyle	top
lbox	true
diagramWidth	1462
revision	13

V2 metadata uses protobuf to serialise the frames' properties to the shared memory buffer. This use of protobuf aligns with the IPC protocol but also allows support for optional fields and for fields to be added and removed without causing backward/forward compatibility issues. It also supports variable length fields so the MKS ID, IV & sub-sample information can all be directly encoded in the metadata, avoiding the complexities of interleaving them with the media frames and referencing them with offsets/lengths as used in the V1 metadata format.

enum SegmentAlignment {

  ALIGNMENT_UNDEFINED = 0;
  ALIGNMENT_NAL       = 1;
  ALIGNMENT_AU        = 2;
}

enum CipherMode {

  CIPHER_MODE_UNDEFINED = 0;
  CIPHER_MODE_CENC      = 1;  /* AES-CTR scheme */
  CIPHER_MODE_CBC1      = 2;  /* AES-CBC scheme */
  CIPHER_MODE_CENS      = 3;  /* AES-CTR subsample pattern encryption scheme */
  CIPHER_MODE_CBCS      = 4;  /* AES-CBC subsample pattern encryption scheme */
}


message MediaSegmentMetadata {

     required optional uint32                 length               = 1;             /* Number of bytes in sample */

     required optional sint64                 time_position        = 2;             /* Position in stream in nanoseconds */

     required optional sint64                 sample_duration      = 3;             /* Frame/sample duration in nanoseconds */

     required optional uint32                 stream_id            = 4;             /* stream id (unique ID for ES, as defined in attachSource()) */

    optional uint32                 sample_rate          = 5;             /* Samples per second for audio segments */

    optional uint32                 channels_num         = 6;             /* Number of channels for audio segments */

    optional uint32                 width                = 7;             /* Frame width in pixels for video segments */

    optional uint32                 height               = 8;             /* Frame height in pixels for video segments */

    optional SegmentAlignment       segment_alignment    = 9;             /* Segment alignment can be specified for H264/H265, will use NAL if not set */

    optional bytes                  extra_data           = 10;            /* Buffer containing extradata */

    optional bytes                  media_key_session_id = 11;            /* Buffer containing key session ID to use for decryption */

    optional bytes                  key_id               = 12;            /* Buffer containing Key ID to use for decryption */

    optional bytes                  init_vector          = 13;            /* Buffer containing the initialization vector for decryption */

    optional uint32                 init_with_last_15    = 14;            /* initWithLast15 value for decryption */

    optional repeated SubsamplePair sub_sample_info      = 15;            /* If present, use gather/scatter decryption based on this list of clear/encrypted byte lengths. */

                                                                          /* If not present and content is encrypted then entire media segment needs decryption (unless    */

                                                                          /* cipher_mode indicates pattern encryption in which case crypt/skip byte block value specify    */

                                                                          /* the encryption pattern)                                                                       */

    optional bytes                  codec_data           = 16;            /* Buffer containing updated codec data for video segments */

    optional CipherMode             cipher_mode          = 17;            /* Block cipher mode of operation when common encryption used */

    optional uint32                 crypt_byte_block     = 18;            /* Crypt byte block value for CBCS cipher mode pattern */

    optional uint32                 skip_byte_block      = 19;            /* Skip byte block value for CBCS cipher mode pattern */
    optional Fraction               frame_rate           = 20;            /* Fractional frame rate of the video segments */

message SubsamplePair

{

     optional required uint32_t               num_clear_bytes      = 1;             /* How many of next bytes in sequence are clear */

    optional  required uint32_t               num_encrypted_bytes  = 2;             /* How many of next bytes in sequence are encrypted */

}

...

PlantUML Macro

format	SVG
title	Render Frame

@startuml

autonumber

box "Container" #LightGreen
participant Netflix
participant DPI
participant rialtoClient
end box

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

Netflix            ->  DPI:              renderFrame()
DPI                ->  rialtoClient:     renderFrame()
rialtoClient       ->  rialtoServer:     renderFrame()
opt Frame renderable
rialtoServer       ->  GStreamer_server: Trigger rendering of frame

optrialtoServer Frame rendered successfully

note across: It is a Netflix requirement to call updatePlaybackPosition() after renderFrame()--> rialtoClient:     status=true
else renderFrame() called in bad state
rialtoServer       --> rialtoClient:     notifyPosition(position)status=false
end

rialtoClient       --> DPI:              notifyPosition(position)status
DPI                --> Netflix:          updatePlaybackPosition(pts)

rialtoServer       --> rialtoClient:     status=true
else
rialtoServer       --> rialtoClient:     status=false
end

else renderFrame() called in bad state
rialtoServer       --> rialtoClient:     status=false
end

rialtoClient
@enduml

Media data pipeline

Note that the data pipelines for different data sources (e.g. audio & video) should operate entirely independently. Rialto should

attempt to keep the shm buffer as full as possible by requesting a refill for that source whenever the source's memory buffer is empty
attempt to push all available frames for a source to GStreamer, i.e. push until Gstreamer indicates that it can accept no more data

Cobalt to Gstreamer

PlantUML Macro

format	SVG
title	Cobalt pushing media frames

@startuml

autonumber

box "Container" #LightGreen
participant Cobalt
participant Starboard
participant GStreamer_client_appsrc
participant decrypter_element
participant ocdmProxy
end box


Cobalt       -                 ->  DPI:Starboard:                    SbPlayerWriteSample2(player, sample[])
note right: Currently  status
DPIsample array size must be 1
Starboard                     -->  Netflix:Starboard:                    status

@enduml

Media data pipeline

Note that the data pipelines for different data sources (e.g. audio & video) should operate entirely independently. Rialto should

attempt to keep the shm buffer as full as possible by requesting a refill for that source whenever the source's memory buffer is empty
attempt to push all available frames for a source to GStreamer, i.e. push until Gstreamer indicates that it can accept no more data

Cobalt to Gstreamer

PlantUML Macro

format	SVG
title	Cobalt pushing media frames

@startuml

autonumber

box "Container" #LightGreen
participant Cobalt
participant Starboard
participant GStreamer_client_appsrc
participant decrypter_element
participant ocdmProxy
end box


CobaltCreate GstBuffer and add media data from sample to it

opt Sample encrypted
Starboard                     ->  GStreamer_client_appsrc:      gst_buffer_add_protection_meta(gst_buffer, decrytion_params)
end


Starboard         ->  Starboard:          ->  GStreamer_client_appsrc:        SbPlayerWriteSample2(player, sample[])
note right: Currently sample array size must be 1
Starboardgst_app_src_push_buffer(app_src, gst_buffer)
GStreamer_client_appsrc       --> decrypter_element:            data flows through client  pipeline
decrypter_element    ->  Starboard:       ->  decrypter_element:             Create GstBuffer and add media data from sample to it

opt Sample encrypted
Starboardgst_buffer_get_protection_meta(buffer)

opt Implementation before CBCS support added
decrypter_element             ->  ocdmProxy:            ->  GStreamer_client_appsrc:      gstopencdm_buffergstreamer_addsession_protectiondecrypt_metaex(gstkey_session, buffer, sub_samples, iv, kid, decrytion_params)
end


Starboardinit_with_last_15, caps)
ocdmProxy                     ->  GStreamer_client_appsrc:ocdmProxy:              gst_app_src_push_buffer(app_src, gst_buffer)
GStreamer_client_appsrc     Create gst --> decrypter_element:            data flows through client pipeline
decrypter_element             ->  decrypter_element:            gst_buffer_get_protection_meta(buffer)

opt Implementation beforestruct containing encryption data decrytion_params
else Implementation after CBCS support added
decrypter_element             ->  ocdmProxy:                    opencdm_gstreamer_session_decrypt_exbuffer(key_session, buffer, sub_samples, iv, kid, init_with_last_15, caps)
end

ocdmProxy                     ->  ocdmProxy decrypter_element:                    Create gst struct containing encryption data decrytion_params
else Implementation after CBCS support added
decrypter_element             ->  ocdmProxy:                    opencdm_gstreamer_session_decrypt_buffer(key_session, buffer, caps)
end

ocdmProxy       gst_buffer_add_protection_meta(buffer, metadata)
note left
Decryption is deferred until the data is sent to Rialto so
attach the required decryption parameters to the media frame
which are then ready to be passed to Rialto when it requests
more data.
end note

@enduml

Netflix to Rialto Client

PlantUML Macro

format	SVG
title	Netflix to Rialto Client

@startuml

autonumber

box "Container" #LightGreen
participant Netflix
participant DPI
participant rialtoClient
end box

rialtoClient      -/  DPI:      ->  decrypter_element:       notifyNeedMediaData(pipeline_session, sourceId,    gst_buffer_add_protection_meta(buffer, metadata)
note left
Decryption is deferred until the data is sent to Rialto so
attach the required decryption parameters to the media frame
which are then ready to be passed to Rialto when it requests
more data.
end note

@enduml

Netflix to Rialto Client

PlantUML Macro

format	SVG
title	Netflix to Rialto Client

@startuml

autonumber

box "Container" #LightGreen
participant Netflix
participant DPI
participant rialtoClient
end box

rialtoClientframe_count, need_data_request_id, shm_info)
DPI               --> rialtoClient:

opt Cached segment stored from previous need data request
DPI        -/  DPI:     ->  rialtoClient:       notifyNeedMediaData(pipeline_session, sourceId, frame_count, addSegment(need_data_request_id, shmcached_media_infosegment)
DPIrialtoClient      --> DPI:        --> rialtoClient:

opt Cached segment stored from previous need data request
DPI               ->  rialtoClient:     addSegment(need_data_request_id, cached_media_segment)
rialtoClient      --> DPI:              status
note right: status!=OK should never happen here
end

loop While (frames_written < frame_count) && (addSegment() returns OK) && (get_next_media_sample_status == OK)

DPI               -/  Netflix:          getNextMediaSample(es_player, sample_writer)
Netflix           ->  DPI:              initSample(sample_writer, sample_attributes)
DPI               ->  DPI:              Cache sample_attributes
DPI               --> Netflix:          status
Netflix           ->  DPI:              write(sample_writer, data)
DPI               ->  DPI:              Create MediaSegment object from data and cached\nsample_attributes (including any decryption attributes)
DPI               ->  rialtoClient:     addSegment(need_data_request_id, media_segment)

opt Encrypted content && key session ID present in map (see Select Key ID)
rialtoClient      ->  rialtoClient:     Set key_id in media_segment to value\nfound in map for this key session ID
note left: MKS ID should only be found in map for Netflix content
end

rialtoClient      --> DPI:              status

opt status==NO_SPACE
DPI  ->  DPI:                           Cache segment for next need data request
note right
This will require allocating temporary
buffer to store the media data but this
should happen very rarely in practise.

*TODO:* Consider adding canAddSegment()
Rialto API so that initSample() could
return NO_AVAILABLE_BUFFERS to cancel
this request and avoid the need for 
the temporary media data cache.
end note
end

DPI               --> Netflix:          write_status
Netflix           --> DPI:              get_next_media_sample_status
end

opt get_next_media_sample_status == OK
DPI               ->  DPI:              have_data_status = OK
else get_next_media_sample_status == NO_AVAILABLE_SAMPLES
DPI               ->  DPI:              have_data_status = NO_AVAILABLE_SAMPLES
else get_next_media_sample_status == END_OF_STREAM
DPI               ->  DPI:              have_data_status = EOS
else
DPI               ->  DPI:              have_data_status = ERROR
end

DPI               ->  rialtoClient:     haveData(pipeline_session, have_data_status, need_data_request_id)


opt Data accepted

opt Frames pushed for all attached sources && buffered not sent
rialtoClient      -/  DPI:              notifyNetworkState(NETWORK_STATE_BUFFERED)
end

rialtoClient      --> DPI:              OK
else Errror
rialtoClient      --> DPI: ERROR
rialtoClient      -/  DPI:              notifyPlaybackState(PLAYBACK_STATE_FAILURE)
end

opt First video frame at start of playback or after seek ready for rendering
opt notifyFrameReady not currently implemented
rialtoClient      -/  DPI:              notifyFrameReady(time_position)
else
rialtoClient      -/  DPI:              notifyPlaybackState(PLAYBACK_STATE_PAUSED)
end
DPI               -/  Netflix:          readyToRenderFrame(pts=time_position)
end

@enduml

...

PlantUML Macro

format	SVG
title	Server only mode

@startuml

autonumber

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

rialtoServer      -/  client:           notifyNeedMediaData(pipeline_session, sourceId, frameCount, maxBytes, needDataRequestId, shmInfo)
client            ->  client:           Ignore shmInfo
client            --> rialtoServer:

loop While (framesFetched < frameCount) && (addSegment() returns OK)
client            ->  client:           Get next frame & any decryption metadata
client            ->  rialtoServer:     addSegment(needDataRequestId, segment)

opt needDataRequestId is valid && enough space to write segment and its metadata to shm region && client not trying to send too many frames
rialtoServer      ->  rialtoServer:     Copy segment & metadata to shm buffer based on shmInfo for this request ID
rialtoServer      --> client:           OK
else Not enough space in shm region || client trying to send too many frames
rialtoServer      --> client:           NO_SPACE
else needDataRequestId not found
rialtoServer      --> client:           OK
note right: Silently ignore calls with invalid request ID as this is possible due to race conditions
end



end

note over client
Set status following same rules as in client/server mode
end note
client            ->  rialtoServer:     haveData(pipeline_session, status, needDataRequestId)
note across: From this point processing follows the same flow as shown in the client-server diagram.

@enduml

Note
The code for populating the shm buffer from the parameters to addSegment() will be common on the client & server side so this should be stored in a common location to be used by both implementations.

See also Rialto Client MSE Player Session Streaming State Machine for some additional clarity on how the Rialto client should manage the flow of data in particular regard to seek operations.

Rialto Server to Gstreamer server

This algorithm should be run for all attached sources. A haveData() call in the above sequence can restart the algorithm when it previously stopped due to data exhaustion.

 as in client/server mode
end note
client            ->  rialtoServer:     haveData(pipeline_session, status, needDataRequestId)
note across: From this point processing follows the same flow as shown in the client-server diagram.

@enduml

Note
The code for populating the shm buffer from the parameters to addSegment() will be common on the client & server side so this should be stored in a common location to be used by both implementations.

See also Rialto Client MSE Player Session Streaming State Machine for some additional clarity on how the Rialto client should manage the flow of data in particular regard to seek operations.

Rialto Server to Gstreamer server

This algorithm should be run for all attached sources. A haveData() call in the above sequence can restart the algorithm when it previously stopped due to data exhaustion.

PlantUML Macro

format	SVG
title	Pushing data to Gstreamer server pipeline

@startuml

autonumber

box "Platform" #LightGreen
participant rialtoClient
end box

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

note across
Gstreamer app source uses 2 signals, need-data and enough-data,
to notify its client whether it needs more data. Rialto server
should only push data when the appsrc indicates that it is in
the need-data state.
end note


loop While appsrc needs data && appsrc data available in shm buffer

rialtoServer       ->  rialtoServer:      Extract frame's metadata from shm
opt Frame encrypted

rialtoServer	   ->  GStreamer_server:  gst_buffer_add_protection_meta(buffer, meta)

end

rialtoServer       ->  GStreamer_server:  Set width/height caps
opt new codec_data in frame
rialtoServer       ->  GStreamer_server:  Set codec_data caps
end

rialtoServer       ->  GStreamer_server:  gst_app_src_push_buffer(src, gst_buffer)
rialtoServer       ->  rialtoServer:      'Remove' frame from shm

opt First video frame pushed at start of playback / after seek
note across: Not currently implemented

PlantUML Macro

format	SVG
title	Pushing data to Gstreamer server pipeline

@startuml

autonumber

box "Platform" #LightGreen
participant rialtoClient
end box

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

note across
Gstreamer app source uses 2 signals, need-data and enough-data,
to notify its client whether it needs more data. Rialto server
should only push data when the appsrc indicates that it is in
the need-data state.
end note


loop While appsrc needs data && appsrc data available in shm buffer

rialtoServer       ->  rialtoServer:      Extract frame's metadata from shm
opt Frame encrypted

rialtoServer	--/ rialtoClient:      notifyFrameReady(frame_timestamp)
end

opt Appsrc data exhausted from shm
opt (status == EOS) for this appsrc
rialtoServer       ->   GStreamerGStreamer_server:    gst_buffer_add_protection_meta(buffer, meta)

end
  notify EOS
else Not EOS
rialtoServer       ->  GStreamer_server:  Set width/height caps
opt new codec_data in frame
rialtoServer    --/ rialtoClient:      notifyNeedMediaData(...)
end
end

end

@enduml

Frames are decrypted in the pipeline when they are pulled for playback.

PlantUML Macro

format	SVG
title	Decrypt Frames on Gstreamer server pipeline

@startuml

autonumber

box "Platform" #LightGreen
participant rialtoClient
end box

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

GStreamer_server   ->  GStreamer_serverrialtoServer:    Set codec_data caps
end decrypt(buffer)

rialtoServer  	     ->  GStreamer GStreamer_server:  gst_appbuffer_srcget_pushprotection_meta(buffer(src, gst_buffer)
)
 
opt Protection Meta exists (Frame encrypted)
 
rialtoServer       ->  rialtoServer:      'Remove'Extract frame's from shmmetadata

opt First video frame pushed at start of playback / after seek
note across: Not currently implemented
rialtoServermedia_keys.key_system == "com.netflix.playready"
rialtoServer       ->  Ocdm:       --/ rialtoClient:      notifyFrameReady(frame_timestampopencdm_select_key_id(ocdm_session, kid)
end


opt AppsrcImplementation databefore exhaustedCBCS fromsupport shm
opt (status == EOS) for this appsrc
rialtoServeradded
rialtoServer       ->  Ocdm:              ->  GStreamer_server:      notify EOS
else Not EOSopencdm_gstreamer_session_decrypt_ex(ocdm_session, gst_buffer, subsample_info, iv, key, init_with_last_15, caps)
else Implementation after CBCS support added
rialtoServer       --/>  rialtoClientOcdm:            notifyNeedMediaData(...)
end   opencdm_gstreamer_session_decrypt_buffer(ocdm_session, gst_buffer, caps)
end

end

@enduml

Playback State

Position Reporting

The position reporting timer should be started whenever the PLAYING state is entered and stopped whenever the session moves to another playback state, i.e. stop polling during IDLE, BUFFERING, SEEKING etc.Frames are decrypted in the pipeline when they are pulled for playback.

PlantUML Macro

format	SVG
title	Decrypt Frames on Gstreamer server pipelinePosition updates

@startuml


autonumber

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

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

GStreamer_server== Regular position ->update notifications rialtoServer:      decrypt(buffer)

rialtoServer	==

rialtoServer     ->   GStreamer_serverrialtoServer:  gst_buffer_get_protection_meta(buffer)
 
opt Protection MetaPosition exists (Frame encrypted)
 timer fired
rialtoServer       ->  rialtoServerGStreamer_server: Get position from pipeline
GStreamer_server --> rialtoServer: Extract frame's metadata

opt media_keys.key_system == "com.netflix.playready"
rialtoServer   Current position
rialtoServer     ->/  OcdmrialtoClient:     notifyPosition(pipeline_session, position)
rialtoClient     -/    opencdm_select_key_id(ocdmGStreamer_client: notifyPosition(pipeline_session, kidposition)
end


opt Implementation before CBCS support added
rialtoServer       ->  Ocdm:   note over GStreamer_client: Not used by Cobalt as some conformance\ntests require very high position accuracy


== Get position ==

Cobalt           opencdm_gstreamer_session_decrypt_ex(ocdm_session, gst_buffer, subsample_info, iv, key, init_with_last_15, caps)
else Implementation after CBCS support added
rialtoServer->  Starboard:        SbPlayerGetInfo2(player)
Starboard        ->  Ocdm:              opencdm_gstreamer_session_decrypt_buffer(ocdm_session, gst_buffer, caps)
end

end

@enduml

Playback State

Position Reporting

The position reporting timer should be started whenever the PLAYING state is entered and stopped whenever the session moves to another playback state, i.e. stop polling during IDLE, BUFFERING, SEEKING etc.

PlantUML Macro

format	SVG
title	Position updates

@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

== Regular position update notifications ==

rialtoServer     ->  rialtoServer:     Position timer fired
rialtoServerGStreamer_client: Get position
GStreamer_client ->  rialtoClient:     getPosition(pipeline_session)
rialtoClient     ->  rialtoServer:     getPosition(pipeline_session)
rialtoServer     ->  GStreamer_server: Get position from pipeline
GStreamer_server --> rialtoServer:     position
rialtoServer     --> rialtoClient:     position
rialtoClient     --> GStreamer_client: position
GStreamer_client --> Starboard:        position
Starboard        ->  GStreamer_serverStarboard: Get position from pipeline
GStreamer_server --> rialtoServer:  Set   Currentplayer_info.pos = position
rialtoServerStarboard        --/>  rialtoClientCobalt:     notifyPosition(pipeline_session, position)
rialtoClient     -/ player_info

@enduml

End of stream

PlantUML Macro

format	SVG
title	End of stream

@startuml

autonumber

box "Container" #LightGreen
participant Cobalt
participant Starboard
participant GStreamer_client: notifyPosition(pipeline_session, position)
note over GStreamer_client: Not used by Cobalt as some conformance\ntests require very high position accuracy


== Get position ==

Cobalt    
participant rialtoClient
end box

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

opt End of content reached
GStreamer_server   -/  rialtoServer:         GST_MESSAGE_EOS
rialtoServer       ->/  StarboardrialtoClient:         SbPlayerGetInfo2(player)
Starboard notifyPlaybackState(pipeline_session, END_OF_STREAM)
rialtoClient       ->/  GStreamer_client: Get position    notifyPlaybackState(pipeline_session, END_OF_STREAM)
note left
This should notify all attached sinks of EOS
end note
GStreamer_client   ->/  rialtoClientStarboard:     getPosition(pipeline_session)
rialtoClient     ->  rialtoServer:GST_MESSAGE_EOS
Starboard     getPosition(pipeline_session)
rialtoServer     ->/  GStreamer_serverCobalt: Get position from pipeline
GStreamer_server --> rialtoServer:     position
rialtoServer    PlayerStatus(player, kSbPlayerStateEndOfStream)
end

@enduml

Underflow

PlantUML Macro

format	SVG
title	Underflow

@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 --> rialtoClient:     position
rialtoClient     --> GStreamer_client: position
GStreamer_client --> Starboard:        position
Starboard        ->  StarboardGStreamer_server:     g_signal_connect(video_decoder, getVideoUnderflowSignalName_soc(),  Set player_info.pos = position
Starboard        video_underflow_cb, user_data);
GStreamer_server   --> CobaltrialtoServer:           player_info

@enduml

End of stream

PlantUML Macro

format	SVG
title	End of stream

@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

opt End of content reached    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 GST_MESSAGE_EOSremoved
rialtoServer       -/>  rialtoClientGStreamer_server:         notifyPlaybackState(pipeline_session, END_OF_STREAM)
rialtoClientg_signal_handler_disconnect(video_decoder, video_handler_id);
GStreamer_server   --> rialtoServer:
end

opt Audio source removed
rialtoServer       -/ > GStreamer_clientserver:     notifyPlaybackState(pipeline_session, END_OF_STREAM)
note left
This should notify all attached sinks of EOS
end note
GStreamer_clientg_signal_handler_disconnect(audio_decoder, audio_handler_id);
GStreamer_server   --> rialtoServer:
end


== Underflow ==

opt Data starvation in server AV pipeline
GStreamer_server   -/  StarboardrialtoServer:         video_underflow_cb() or  GSTaudio_MESSAGE_EOS
Starboard          -/  Cobalt:               PlayerStatus(player, kSbPlayerStateEndOfStream)
end

@enduml

Underflow

PlantUML Macro

format	SVG
title	Underflow

@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
rialtoServerunderflow_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_serverclient:      g_signal_connect(video_decoder, getVideoUnderflowSignalName_soc(), video_underflow_cb, user_data);
GStreamer_server   --> rialtoServer:  notifyBufferUnderflow(source_id)
GStreamer_client   -/  Starboard:            emit video_underflow_cb() or videoaudio_handlerunderflow_idcb()
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);
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

Non-fatal Playback Failures

Decryption: Any encrypted frames that fail to decrypt are dropped, and an error notification is propagated to the rialto-gstreamer, at which point a decryption error is raised on the sink.

PlantUML Macro

format	SVG
title	Non-fatal Errors

@startuml

autonumber

box "Container" #LightGreen
participant Application
participant rialtoGstreamer
participant rialtoClient
end box

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

== Decryption ==
GStreamer_server   -->  rialtoServer:
end

opt Audio source removed
rialtoServer          decrypt(buffer)

rialtoServer	   ->  GStreamer_server:  MediaKeyErrorStatus::Fail
GStreamer_server   ->  GStreamer_server:     g_signal_handler_disconnect(audio_decoder, audio_handler_id);
GStreamer_server   --> rialtoServer:
end


== Underflow ==

opt Data starvation in server AV pipelineGST_BASE_TRANSFORM_FLOW_DROPPED 

note over GStreamer_server
Frame is dropped but playback is unaffected.
end note 

GStreamer_server   -/>  rialtoServer:         video_underflow_cb() or audio_underflow_cb()GST_MESSAGE_WARNING(src, GST_STREAM_ERROR_DECRYPT)

rialtoServer          -/  rialtoClient rialtoClient:         notifyBufferUnderflow(source_id notifyPlaybackError(MediaSourceType, PlaybackError::DECRYPTION)
rialtoClient       -/  GStreamer_client:     notifyBufferUnderflow(source_id)
GStreamer_client   -/  Starboard:            emit video_underflow_cb() or audio_underflow_cb()
 rialtoGstreamer:   notifyPlaybackError(MediaSourceType, PlaybackError::DECRYPTION)
 
note over Starboard, GStreamer_client
Starboard does not have any support for underflow
so the event can be ignored for this integrationrialtoGstreamer
Posting an error message on the sink make the\n
sink unable to continue playing back content.
end note

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

end  GST_MESSAGE_ERROR(sink, GST_STREAM_ERROR_DECRYPT)

@enduml

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RDK Support

Archives

Versions Compared

Old Version 22

New Version Current

Key

Media data pipeline

Cobalt to Gstreamer

Media data pipeline

Cobalt to Gstreamer

Netflix to Rialto Client

Netflix to Rialto Client

Rialto Server to Gstreamer server

Rialto Server to Gstreamer server

Playback State

Position Reporting

Playback State

Position Reporting

End of stream

Underflow

End of stream

Underflow

Non-fatal Playback Failures

RDK Resources

[*RDK Preferred*]

Code Management Facility

RDK Forums

[RDK Conferences]

RDK Support

Archives

Page History

Versions Compared

Old Version 22

New Version Current

Key

Media data pipeline

Cobalt to Gstreamer

Media data pipeline

Cobalt to Gstreamer

Netflix to Rialto Client

Netflix to Rialto Client

Rialto Server to Gstreamer server

Rialto Server to Gstreamer server

Playback State

Position Reporting

Playback State

Position Reporting

End of stream

Underflow

End of stream

Underflow

Non-fatal Playback Failures

[RDK Preferred]