# Fragment/chunk IDs on HDS and HLS

**URL:** <https://community.wowza.com/t/fragment-chunk-ids-on-hds-and-hls/45891>\
**Category:** Wowza Streaming Engine\
**Created:** [September 3, 2015, 3:47pm UTC](https://community.wowza.com/t/fragment-chunk-ids-on-hds-and-hls/45891 "2015-09-03T15:47:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Richard\_van\_der\_Hoff](https://avatars.discourse-cdn.com/v4/letter/r/73ab20/32.png) [@Richard\_van\_der\_Hoff](https://community.wowza.com/u/Richard_van_der_Hoff)\
**Post date:** [September 3, 2015, 3:47pm UTC](https://community.wowza.com/t/fragment-chunk-ids-on-hds-and-hls/45891/1 "2015-09-03T15:47:16Z")

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Hello,

When I publish a live stream to Flash Media Server, it assigns HDS Fragment IDs and HLS chunk numbers based on the RTMP timestamps. The benefit of this is that if I am using multiple bitrates, or redundant media servers, the chunk numbers are guaranteed to stay in sync.

Is it possible to achieve the same thing with Wowza?

Thanks!

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<div class="post-metadata">

**Author:** ![Richard\_van\_der\_Hoff](https://avatars.discourse-cdn.com/v4/letter/r/73ab20/32.png) [@Richard\_van\_der\_Hoff](https://community.wowza.com/u/Richard_van_der_Hoff)\
**Post date:** [September 4, 2015, 8:27am UTC](https://community.wowza.com/t/fragment-chunk-ids-on-hds-and-hls/45891/2 "2015-09-04T08:27:42Z")

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[calculateChunkIDBasedOnTimecode](http://community.wowza.com/t/-/39536) sounded promising, but on closer inspection, does not appear to do what I need (“It will not sync chunks between servers which I think you are looking for.”).

I gather there is a hook which allows custom configuration of chunk IDs for HLS (see [List chunks on an HLS live stream](http://community.wowza.com/t/-/34084)), which might solve this problem for HLS. Is there anything similar for HDS?