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Viblast Documentation

Configuration Parameters

Configuration parameters can be passed on to Viblast Player in HTML or in JavaScript.

In HTML, each of them has to be prefixed by "data-viblast-", for instance <video data-viblast-chunks-per-hls-entry="4" ...></video>

In JavaScript, they have to be written in camel case, e.g.

   chunksPerHlsEntry: 4,

Here is a list of all the configuration parameters that can be set on Viblast Player.


  • stream (string) : URL of the cdn stream that will be delivered using Viblast
  • cdn-stream (string) : a synonym for cdn-stream
  • key (string) : License Key
  • log (string) : one of error, warning, info, verbose.
  • remuxer-log (string): one of error, warning, info, verbose
  • forceHEAAC (switch on/off) : Force usage of HE-AAC. Same as he-aac.
  • he-aac (switch on/off) : Force usage of HE-AAC. Same as forceHEAAC.
  • abr (switch on/off) : Enables/Disables auto adaptive bitrate support
  • initial-abr-index (integer) : The index of the sub-playlist to be used as the initial playlist when a variant playlist is provided
  • abr-consider-dimensions (switch on/off) : Take into consideration the current player width and height when choosing the best stream alternative

Under The Hood Parameters

Please note that the name or meaning of any of these parameters may change in future versions

  • low-buffer-level (double) : If the buffer level (in seconds) drop below this level, Viblast will start requesting additional chunks
  • playlist-starting-offset (double) : Start playing from this offset. Example: if set to 0.2 then playback will start 20% inside the CDN playlist.
  • chunks-per-hls-entry (integer) : The number of fragments to fragment a CDN entry into.
  • base-url (string) : This url will be used for loading additional resources required by Viblast. Here you can find more info.
  • append-timestamps (switch on/off) : Append or not timestamp='timestamp' to every request. Helps with browser caches when the same names are reused for different chunks.
  • max-requested-chunks-from-cdn (integer) : The maximum number of open chunk request from the CDN
  • buffer-while-paused (switch on/off) : If on, Viblast will continue downloading chunks while the player is paused until its buffer is full
  • playlist-timeout (integer) : Playlist download timeout
  • vod-buffer-size (integer) : the number of chunks (HLS segments or DASH segments) to buffer in video-on-demand streaming
  • audio (switch on/off) : indicates presence/lack of audio. If there is no audio in the stream and you've failed to set this parameter as false, the playback won't start.
  • video (switch on/off) : indicates presence/lack of video. If there is no video in the stream and you've failed to set this parameter as false, the playback won't start.
  • long-pause-timeout (double) : Discard old content if player has been paused for that long
  • av-gap-correction (switch on/off) : Enables/Disables correction for gaps in video/audio in HLS remuxer

PDN (Peer-assisted Delivery Network)

PDN extends your streaming infrastructure with peer-assisted video delivery. See here for more information.

  • enable-pdn (switch on/off) : Enables/Disables PDN optimization
  • webrtc-log (string) : one of error, warning, info, verbose.
  • window-size (integer) : The number of chunks to keep in the current window.
  • share-segment-size (switch on/off) : Share segment sizes. Speeds up range requests.
  • peer-in (integer) : Sets maximal number of incoming connections per peer
  • peer-out (integer) : Sets maximal number of outgoing connections per peer
  • active-chunk-requests-per-peer (integer) : Set the maximal number of active chunk request per peer
  • connect-to-swarm (switch on/off) : Toggles whether this peer should connect to other peers or not
  • piece-size (integer) : The size of the piece. This value is used to split a chunk input multiple pieces so that it can be sent using webrtc datachannel
  • use-checksums (switch on/off) : do checksumming as a protection mechanism against bad peers and connections
  • comm-station (string) : Default Comm station url
  • deblacklist-peers-timeout (integer) : timeout before we get peers from the blacklist
  • enable-realtime-logger (switch on/off) : Enables/Disables realtime logging
  • realtime-logger-server (string) : Server URL for realtime logging