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Thread: ESPixelStick - grouping, zigzag, effects, and mqtt goodies

  1. #31
    Join Date
    Dec 2018
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    Winnipeg, MB
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    Default Re: ESPixelStick - grouping, zigzag, effects, and mqtt goodies

    Quote Originally Posted by jchuchla View Post
    Not a great idea. DDP is unicast only and has no other mechanism for timing sync.
    Sent from my iPhone using Tapatalk
    What is wrong with unicast?

    Also not sure what you mean by "DDP...has no other mechanism for timing sync".
    The spec seems to indicate there are a couple of methods for synchronization between devices - the push flag and the timecode.
    http://www.3waylabs.com/ddp/

  2. #32
    Join Date
    Nov 2011
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    Default Re: ESPixelStick - grouping, zigzag, effects, and mqtt goodies

    Every Unicast packet is subject to link layer acknowledgement on the WiFi radio link. So right off the bat that doubles the number of time shares that each packet needs. And if the packet fails to arrive or be acknowledged, and that is very common in WiFi links, It will repeat until it does. Often up to 10 attempts. All the while itís delaying the rest of the packets. During this process the data becomes stale. Itís no longer in time with the music. This lag is nondeterministic and subject to network conditions so thereís no way to compensate for it on the player side.

    DDP synchronizes the frame to itself, but not to the sender. The receiver doesnít update the lights until the last packet of the frame is received. So the whole frame is in fact refreshed at once. But depending on the network delay from the first packet in the frame to the let packet, that packet with the sync byte is no longer synced to the source by the time it arrives at its destination. In order to sync the whole system youíd need something like a master clock using PTP protocol or something like that out of band from the data packets. DDP doesnít do that. Nor does sACN. But the potential delay is far less on a well tuned multicast only WiFi network so its not really an issue. The data doesnít go stale with multicast. The data thatís arriving is always fresh.


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  3. #33
    Join Date
    Jan 2016
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    Richmond, TX
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    Default Re: ESPixelStick - grouping, zigzag, effects, and mqtt goodies

    Quote Originally Posted by mrGrumpy View Post
    I just bought 10 from AilExpressÖ.they were not marked as PUYA, but they did not program (they went thru the process with error, but cannot connect or find IP with several different tools.)
    I had the JOY of replacing 10 memory chips.....I was hoping those days were over.
    Argh! PUYA! 20 of them.....

    Waiting for Arduino core for ESP8266 2.5.0-beta3!
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