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Player-NLC Remote Video Stream Path (Read/Seek)

Scope

This document covers only the path where media is streamed from a remote peer into Player-NLC using file-transfer streaming semantics (remote read, seek, stream control).

It does not cover camera-live MJPEG broadcast paths.

Entry Path: GUI -> Player-NLC Stream Mode

  1. A stream asset is launched via Player-NLC.
  2. AppletPlayerNlcBase::playAsset(...) checks assetInfo.isStream() and routes to playStream(...).

  3. AppletPlayerNlcBase::playStream(...) starts two coordinated paths:

  4. GetVirtStreamMgr().fromGuiPlayStream(...) to initialize virtual remote file state.

  5. IMediaPlayerRequests::getNlcPlayer().fromGuiPlayStream(...) to start the player module in stream mode.

Code:

Stream Session Setup

VirtStreamMgr::fromGuiPlayStream(...) prepares the stream session:

  1. Copies stream asset metadata into m_LiveStream and forces isStream=true.
  2. Stores local session id.
  3. Resolves best connection to the remote owner (assetInfo.getDestUserId()).
  4. Registers for file-transfer callbacks.
  5. Calls PluginFileShareClient::startStream(...).

PluginFileShareClient::startStream(...) converts the asset to FileInfo (stream=true) and starts transfer via FileInfoXferMgr::startDownload(...).

Code:

Remote Read Path

The player reads via virtual file APIs; the stream manager serves bytes from remote-fed caches.

1) Virtual file open

  • VirtStreamMgr::fileOpen(...) selects virtual stream handling.
  • VirtStreamMgr::virtFileOpen(...) validates requested file name against active stream asset and creates m_LiveStream.m_VFile with logical file length.

Code:

2) Virtual read

  • VirtStreamMgr::fileRead(...) dispatches to virtFileRead(...) for virtual stream files.
  • virtFileRead(...):
  • Computes readAttemptLen based on file length and current offset.
  • Calls waitForStream(fileOffs, readAttemptLen).
  • Reads bytes from m_FileTail first (if present), else from m_StreamCache.
  • Advances virtual file offset when full read succeeds.

Code:

3) How cache gets filled

  • Incoming transfer packets are delivered to VirtStreamMgr::onFileXferPktRxed(...).
  • PKT_TYPE_FILE_CHUNK_REQ is handled by onPktFileChunkReq(...) and written into m_StreamCache at packet chunk offsets.
  • Optional tail data arrives as PKT_TYPE_STREAM_CTRL_REPLY with eStreamReadTail and is written into m_FileTail.

Code:

Remote Seek Path

1) User seek from Player-NLC UI

  • Slider change triggers AppletPlayerNlcBase::slotSliderChanged(...).
  • UI sends seek request to player module with fromGuiMediaPlayerSeek(sliderPos).

Code:

2) Virtual stream seek decision

  • VirtStreamMgr::virtFileSeek(...) updates logical offset.
  • If target position is not already in cache/tail, it sends stream control seek:
  • sendStreamSeek(newPos)
  • Builds PktStreamCtrlReq with eStreamSeek, session ids, asset id, and start offset.

Code:

3) Server-side seek handling

  • Engine routes PKT_TYPE_STREAM_CTRL_REQ to FileShareServer plugin.
  • FileInfoXferMgr::onPktStreamCtrlReq(...) handles eStreamSeek:
  • Finds TX session by stream session id.
  • Seeks sender file handle to requested offset.
  • Updates transfer offset for subsequent chunk sends.
  • Sends stream control reply back.

Code:

Stop/End Teardown

When playback stops or ends in Player-NLC:

  1. AppletPlayerNlcBase::onPlaybackStopped(...) / onPlaybackEnded(...) calls GetVirtStreamMgr().onPlaybackStopped(...) / onPlaybackEnded(...) when streaming.
  2. VirtStreamMgr::onStreamStop() notifies engine and clears m_LiveStream state/caches.

Code:

Packet Types In This Path

  • PKT_TYPE_FILE_GET_REPLY: establishes stream session mapping (client stores server session id).
  • PKT_TYPE_FILE_CHUNK_REQ: carries streamed file chunks into client stream cache.
  • PKT_TYPE_STREAM_CTRL_REQ (eStreamSeek): client requests remote seek.
  • PKT_TYPE_STREAM_CTRL_REPLY (eStreamReadTail and seek reply): server response/control data.

Code: