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Thread: Live stream sync test for 720p and 1080p 30fps

  1. #1
    Registered User
    Join Date
    Oct 2006
    Fort Worth, Texas

    Live stream sync test for 720p and 1080p 30fps

    Hi all,

    I have been using a simple sync test/aspect ratio test for all of my live stream jobs recently. This works pretty well - at least it does for me.

    How to use:
    1 - Set up the relevant raster size video in a project
    2 - Place in DDR and set to loop
    3 - The video starts with a long tone and then goes to 1-second bursts. The flash-frames coincide with the start of the 1-second burst
    4 - On a reliable, wired computer or mobile/tablet, check the video latency compared to the audio click. Adjust the audio offset using an external audio delay box like the Datavideo AD-100M.

    Realize that the latency will vary for people depending on their connectivity speed but for Q/C purposes, I have found the above testing has helped sync issues.

    Copy and past the URL below in browser to download


    Chuck Johnson
    Big Bad Wolf Creative Group
    Tricaster 460
    Tricaster Control Panel
    Lots of toys to make it all work

  2. #2
    Registered User
    Join Date
    Apr 2008
    Hi Chuck,

    I'm a little confused about using external audio sync delay - if AV is out of sync IN the TriCaster, why not adjust using Audio Delay feature in the Audio Mixer? If Audio/Video is synced in the TriCaster, then any web stream output should also be synced. No?


    Jeff Pulera
    Streaming Broadcast Solutions - Newtek Elite

    TriCasters: Mini with AE, TC1
    Camera: Sony PMW-X70 4K
    Controllers: All variety of XKeys
    PTZ: Newtek NDIHX-PTZ1

  3. #3
    Registered User
    Join Date
    Oct 2006
    Fort Worth, Texas
    Great question Jeff,

    What I didn't explain is that I use an external encoder for my live streaming. I use the TriCaster only for switching (IMAG) and/or recording ISO and mastering.

    I rarely have sync issues internally so yes, I would use the internal delay feature for each input with the sync issue.

    I send SDI out of the TriCaster to my SDI/audio delay box and run the sync video tool through the TriCaster into my encoder, test the sync and adjust audio delay as needed.

    In regards to your second question, one thing I have noticed is that, depending on the encoder bit-rate and the available bandwidth, video may not sync due to the lack of enough bandwidth (Mb/s or Kb/s). That's a moving target in terms of sync issues and this procedure may not help.

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