New post
0

Slip Sync on long movie across 4 screens - Enhanced Sync

Avatar
William Kemp
None
Follow

So... 

We have 4 screens running a 1-hour long movie. This is using the enhanced sync feature. The movies appear to stay perfectly frame synced for the first 15/20 mins and then very quickly become out of sync.

You can see some of the videos attempting to speed up/ stop trying to get back in sync but after a few minutes, they are back out of sync again. After 45 minutes a couple of the movies actually stop.

As soon as the master file ends and starts again all videos perfectly jump back into sync and again stay synced for 15mins until the issue appears again.

The exact same thing happens in Birghtwall mode.

A lot of the basics already checked and tested.

Any advice would be great.

 

Date Votes

6 comments

  • 0
    Avatar
    Allen H. Porter

    Somewhere there is a statement by Brightsign about the sync drifting over time.  My guess is that you use enhanced sync and your master player only sends out the sync at the start of the hour?  I have never tried videos as long as this.  My guess is that you would need to break the video up into smaller segments and have a sync command sent at the start of each.  There may be other ways of doing this that I have not tried.

  • 0
    Avatar
    William Kemp

    Thanks for this. 

    Was trying to work out if this was possible without having the clip stop/ frame of black screen in between each. 

  • 0
    Avatar
    Brandon

    @Allen - the drift-over-time applies when not using Enhanced Synchronization (or BrightWall which requires it), the traditional "fire and forget" sync method.
    When using Enhanced Sync, the players playback clocks are synchronized and they use that to monitor the playback position in the videos.

    Thus, @William, if the media is in any way out of spec, or if its encoded timestamps are inconsistent or have issues, that can trip up Enhanced Sync.
    Also, storage errors will generally "stall" the system, so that can be an issue, as well as media that is in-spec but exceeds the storage's throughput capability.

    See this article for video compatibility, and also keep in mind that even though you specify a particular bitrate to an encoder, it does not mean the actual bitrate stays at/under that specification.  Some encoders spike the bitrate well beyond the specified "constant" and that will definitely cause problems.

    Adobe Media Encoder is one of them, and we have recommended encoding parameters which should apply to other encoders as well here:
    http://support.brightsign.biz/hc/en-us/articles/218067117-How-do-I-use-Adobe-Media-Encoder-to-create-compatible-video-files-

  • 0
    Avatar
    Allen H. Porter

    Good info Brandon.  Thanks very much.  I am obviously rusty with video walls.

  • 0
    Avatar
    William Kemp

    Brandon this is very helpful.

     

    The content isnt coming from us so its hard to tell how "correctly its being built". They are Re Rendering it for us at the moment with the correct setting and standards used. 

     

    Could you explain more about the storge error? There is a moment the system does look like it has Stalled. 


  • 0
    Avatar
    Brandon

    @William - if you submit a support ticket with a download link to your media file, we can check it.

    For H.264 (AVC) files you can also use Bitrate Viewer to check - https://www.videohelp.com/software/Bitrate-Viewer-2
    The bitrate shouldn't spike past 25 Mbps for H.264 content.

    For H.265 (HEVC) files, you can upload it to a 4K-capable player, then view the file properties in the Diagnostic Web Server and add &advanced=1 to the end of the URL - that should give you an additional Media File Analysis button.
    The top graph is the main concern - it shouldn't go over 80 Mbps for H.265 content.

    On the storage, when SD cards run into errors, the card will try to reallocate blocks from the spare block pool - however, it will stop responding while it does this.
    You should see something in the player's system log, accessible from the DWS at http://playerIPaddress/index.html (replace playerIPaddress with the player's LAN IP) in the Log tab.

    Bitrate spikes can stall playback too, so it still could be either or both at play.

    _________________________________________________________________________

    Friendly reminder, the community forum is intended for user-to-user discussion.  It is not regularly monitored. For troubleshooting problems and to ensure a timely answer from a BrightSign representative, please submit a support ticket.

Please sign in to leave a comment.