# How to guarantee accurate time sync of the same video streaming on different mobile devices?

**URL:** <https://community.wowza.com/t/how-to-guarantee-accurate-time-sync-of-the-same-video-streaming-on-different-mobile-devices/54792>\
**Category:** Wowza Streaming Engine\
**Created:** [March 12, 2020, 2:05pm UTC](https://community.wowza.com/t/how-to-guarantee-accurate-time-sync-of-the-same-video-streaming-on-different-mobile-devices/54792 "2020-03-12T14:05:16Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Colab\_Test](https://avatars.discourse-cdn.com/v4/letter/c/90ced4/32.png) [@Colab\_Test](https://community.wowza.com/u/Colab_Test)\
**Post date:** [March 12, 2020, 2:05pm UTC](https://community.wowza.com/t/how-to-guarantee-accurate-time-sync-of-the-same-video-streaming-on-different-mobile-devices/54792/1 "2020-03-12T14:05:16Z")

</div>

I want to stream a video to multiple android devices. I am using Wowza streaming engine and ffmpeg on the server to stream it but not able to synchronize it. Is there any way to pre-configured the time delay across multiple devices and access/read live streaming time status by accessing video frame ID or something similar ?

For example if HLS has time latency of 2-6 seconds than I can configure the Wowza server to stream in 8 seconds, which will guarantee the time sync across multiple devices.

---

<div class="post-metadata">

**Author:** ![Rose\_Power-Wowza\_Com](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/rose_power-wowza_com/32/431_2.png) [@Rose\_Power-Wowza\_Com](https://community.wowza.com/u/Rose_Power-Wowza_Com)\
**Post date:** [March 13, 2020, 2:25pm UTC](https://community.wowza.com/t/how-to-guarantee-accurate-time-sync-of-the-same-video-streaming-on-different-mobile-devices/54792/2 "2020-03-13T14:25:09Z")

</div>

I don’t believe we can, but I am double checking.

---

<div class="post-metadata">

**Author:** ![Rose\_Power-Wowza\_Com](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/rose_power-wowza_com/32/431_2.png) [@Rose\_Power-Wowza\_Com](https://community.wowza.com/u/Rose_Power-Wowza_Com)\
**Post date:** [March 13, 2020, 2:50pm UTC](https://community.wowza.com/t/how-to-guarantee-accurate-time-sync-of-the-same-video-streaming-on-different-mobile-devices/54792/3 "2020-03-13T14:50:31Z")

</div>

There is a `EXT-X-PROGRAM-DATE-TIME` tag that can be added to the manifest which should specify the exact presentation time of a chunk so if the player supports it then it could maybe use it for alignment.  
`[https://tools.ietf.org/html/draft-pantos-http-live-streaming-13#section-3.4.5](https://tools.ietf.org/html/draft-pantos-http-live-streaming-13#section-3.4.5)`  
`[https://www.wowza.com/docs/how-to-control-display-of-program-date-and-time-headers-in-apple-hls-chunklists-for-live-streams-ext-x-program-date-time](https://www.wowza.com/docs/how-to-control-display-of-program-date-and-time-headers-in-apple-hls-chunklists-for-live-streams-ext-x-program-date-time)`

The chances of Android players supporting it are probably slim at best.

Other than that, at this time there is not a whole lot you can do with syncing up device playback until the LL-HLS spec is more widely supported and you’ll be closer to real time.