How accurate is synchronization?

Last Updated: September 18, 2014

Using the legacy Synchronization feature, BrightSign players stay within 1.5 frames or better when synchronized. Using the BrightWall or Enhanced Synchronization features, players stay synchronized within a few milliseconds (i.e. video and images remain frame accurate among screens). See this FAQ to determine which synchronization option is best for your implementation.

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13 Comments

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    Richard Pugh

    Is this still the case or has it improved in the last two years?

    I have a project which requests 'frame accurate sync' and would like to offer brightsign as the solution.

  • 0
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    Alex

    After 5.5 minutes, there's the potential for a 1 frame drift. 5.5 minutes is the optimal number for a video duration. Sync is ideal, if video duration is less than or equal to 5.5 minutes. We have customers sync hour long videos. In this case sync accuracy stay within 1.5 frames in a worst case scenario.

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    Harm van den Berg

    Hello,

    For a museum in Holland we made video triptych with three hd220's connected by an network so they are synchronized, but we experience a big sync problem. More than 125 frames out of sync The files were checked by our Brightsign dealer in Holland. They tried to fix the problem by writing scripts, but they did not solve it. The files are very large (29GB). Is there a solution for this?

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    Alex

    Update the firmware on the HD220 units to the latest version available at Software Downloads page.

    Check out this FAQ:

    http://support.brightsign.biz/entries/21146497-Which-factors-can-affect-a-synchronization-

    Attach your presentation files (the .bpf files) to this thread.

    Download a free program called mediainfo: http://mediainfo.sourceforge.net

    Use mediainfo to open your video files, click on View - Text, save the specs of your videos to notepad, and send 3 text files to us for review.

    The maximum supported bit rate is 25 Mbps. Bit rate spikes (higher than 25Mbps) within the stream will lead to playback problems. You can use this program to see how a video bitrate changes within the stream, and check if there are bit rate spikes higher than 25Mbps: http://www.winhoros.de/docs/bitrate-viewer/download.html

    Run your 3 videos through the bitrate viewer, and send us the print screens with the results.

    The SD card could be the problem. Please read this post:

    http://support.brightsign.biz/entries/22046640-New-FAQ-Preventing-Read-Fatigue

    Test the projects with different SD cards.

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    Harm van den Berg

    Unfortunately I cannot provide .bpf files, because the dealer did the authoring. I can give you three screenshots of Media Inspector analysis:

     

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    Alex

    The videos are out of supported specs.

    The 4.2 level is not supported. The videos must be redone at level 4.1 or lower to work properly on the HD220. Read more about levels here: http://en.wikipedia.org/wiki/H.264

    VBR audio is not supported - audio stream bit rate mode must be constant (CBR).

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    Harm van den Berg

    Redo the videos at level 4.1 is not a problem....but eh...well it takes a few days to render!  A pity the dealer did not mention these specifications. In which software program is it possible to author H.264 CBR and at the same time author AAC CBR? In Final cut pro X / Compressor I cannot author H.264 CBR; it automatically creates a H.264 VBR file. (but in fact it does automatically creates an AAC CBR file); In Premiere Pro CS6 I can author H.264 CBR but cannot not author AAC CBR (it automatically chooses AAC VBR). So for me it is impossible with these software programs to meet the supported spec.

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    Alex

    Try using the settings from this FAQ: http://support.brightsign.biz/entries/460154-How-do-I-create-MOV-videos-using-Final-Cut-and-Compressor-

    See also: http://support.brightsign.biz/entries/170391-How-do-I-convert-my-videos-to-a-compatible-Brightsign-format-

    I think Adobe Premier and TMPGEnc programs should allow you to create mp4 file with CBR audio, but I'm not 100%. You can contact manufacturer and ask.

     

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    Harm van den Berg

    Hi, I did use the template for Compressor in the link above and it creates a H264 VBR (see Media Inspector analysis) The dealer said that it is most important that the H.264 file is CBR. So...what to do?

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    Romeo

    Hi,

    I've never used Compressor, but is it not possible to modify the settings from the template file and select CBR?

    Regards,

    Romeo

     

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    Harm van den Berg

    Unfortunately no. It is possible to adjust a maximum bit rate, but it still creates a VBR. It is possible for the AAC audio to select CBR. I did check other converters (compatible with Mac) in the list mentioned in the link above, but none of them (except for Premiere Pro) authors CBR video files. Problem in Premiere is that it cannot author AAC CBR.

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    Alex

    Is it possible to remove the audio from the files, or audio is the absolute requirement? If audio should present, re-encode the videos at 4.1 profile (CBR video) and VBR audio, and re-test. You should be using the same SD cards, same brand and class. Update the firmware on the units to the latest beta version 4.7.96.

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    Konstantin Gast

    is the information about the 4.1 profile requirement still valid? we had some playback issues with our last brightwall project and from now on want to be able to give the customer specific requirements regarding the used codec.

    my current Informations are:

    Codec: H264
    Video Bit Rate: VBR max 25 Mbps
    Profile: Main(?)
    Level: max. 4.1

    Audio Bit Rate: CBR

    used Brightsign Model is: HD1022

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