# DASH Closed Captioning from an MP4 with embedded TTML

**URL:** <https://community.wowza.com/t/dash-closed-captioning-from-an-mp4-with-embedded-ttml/47354>\
**Category:** Wowza Streaming Engine\
**Created:** [September 26, 2016, 5:32pm UTC](https://community.wowza.com/t/dash-closed-captioning-from-an-mp4-with-embedded-ttml/47354 "2016-09-26T17:32:45Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Bill\_McLaughlin](https://avatars.discourse-cdn.com/v4/letter/b/c0e974/32.png) [@Bill\_McLaughlin](https://community.wowza.com/u/Bill_McLaughlin)\
**Post date:** [September 26, 2016, 5:32pm UTC](https://community.wowza.com/t/dash-closed-captioning-from-an-mp4-with-embedded-ttml/47354/1 "2016-09-26T17:32:45Z")

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I have mp4 files with embedded TTML data as a text track. When I upload these to my VOD application in Wowza Streaming Engine though, the MPD manifest for Dash is not including the text track.

Is this expected to work? If so, any pointers on what the track type has to be in the mp4 files, etc. for Wowza to find it and use it?

Thanks!

Bill

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**Author:** ![Fabian\_Blunck](https://avatars.discourse-cdn.com/v4/letter/f/71e660/32.png) [@Fabian\_Blunck](https://community.wowza.com/u/Fabian_Blunck)\
**Post date:** [October 11, 2016, 11:57pm UTC](https://community.wowza.com/t/dash-closed-captioning-from-an-mp4-with-embedded-ttml/47354/2 "2016-10-11T23:57:17Z")

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Hey Bill,

I have the same problem…

But as you can read [here](http://community.wowza.com/t/-/46935) wowza doesn’t seem to support cc yet.

Greetings,

Fabian

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**Author:** ![Andy\_Engberson](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/andy_engberson/32/392_2.png) [@Andy\_Engberson](https://community.wowza.com/u/Andy_Engberson)\
**Post date:** [November 10, 2016, 8:44pm UTC](https://community.wowza.com/t/dash-closed-captioning-from-an-mp4-with-embedded-ttml/47354/3 "2016-11-10T20:44:35Z")

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Hello,

For now when using DASH you will have to use WebVTT sidecar files.

There is a fix for this feature that is still marked as Preview in the recent [Engine update](https://www.wowza.com/docs/wowza-streaming-engine-software-updates#updaters).

_Fixed support for “sidecar” WebVTT caption files in on-demand MPEG-DASH streaming (preview feature)_

Since this is marked as a “Preview” feature it is still not recommended for production delivery, but this is the option that is currently available.

Do note that active maintenance and support is required to access the latest update installers.

Regards,

Andy\_E

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**Author:** ![Bill\_McLaughlin](https://avatars.discourse-cdn.com/v4/letter/b/c0e974/32.png) [@Bill\_McLaughlin](https://community.wowza.com/u/Bill_McLaughlin)\
**Post date:** [October 12, 2016, 9:15am UTC](https://community.wowza.com/t/dash-closed-captioning-from-an-mp4-with-embedded-ttml/47354/4 "2016-10-12T09:15:19Z")

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I have been also talking to a Wowza engineer through support ticket. The current recommendation is to use a WebVTT sidecar for closed captioning with DASH.

Unfortunately, the MP4 embedded TTML track is not supported yet, though they may add this in a future release.

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**Author:** ![Fabian\_Blunck](https://avatars.discourse-cdn.com/v4/letter/f/71e660/32.png) [@Fabian\_Blunck](https://community.wowza.com/u/Fabian_Blunck)\
**Post date:** [October 25, 2016, 1:27am UTC](https://community.wowza.com/t/dash-closed-captioning-from-an-mp4-with-embedded-ttml/47354/5 "2016-10-25T01:27:27Z")

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Hey,

how do you do it?

I still can’t get it to work 😕

I’ve added ttml, srt and vtt to my SMIL, but getting no entry in the MPD file.

Greetings,

Fabian