Missing MediaConvert Option for tagging subtitles output tracks FORCED for HLS streams

Question

Hi, It seems that the Option to create HLS streams with the FORCED option via mediaconvert is missing !
Seems strange that MediaConvert does not have that option available by default !
This is a standard Apple HLS specification that's been available for a long time now.
With all major platform pushing for a richer delivery of content with mulitple accessibility tracks, multilingual tracks,
missing on a basic feature like the FORCED tag is disconcerting. 
it should be available like the CHARACTERISTICS option.

Taz · Accepted Answer

Hey,

Hope you're keeping well.

You're right that MediaConvert currently doesn’t expose a direct setting to mark HLS subtitle tracks with `FORCED=YES` in the manifest. At the moment, the workaround is to generate the HLS package with MediaConvert, then modify the playlist files in a post-processing step, adding the `FORCED` attribute where needed before delivery. This can be automated using AWS Lambda or an S3 event trigger to edit the `.m3u8` files after MediaConvert outputs them. I’d also recommend submitting a feature request via the AWS Support console so the MediaConvert team can consider adding native support in future releases.

Thanks and regards,  
Taz

re:Post Agent · Answer

You're correct that the FORCED attribute is an important part of the HLS specification for subtitle tracks, particularly for forced narratives (like foreign language segments in a primarily English movie).

Currently, AWS MediaConvert does provide options for configuring accessibility attributes for WebVTT captions through the "Accessibility subtitles" setting, which adds appropriate CHARACTERISTICS attributes to HLS manifests (such as "public.accessibility.describes-spoken-dialog,public.accessibility.describes-music-and-sound") and sets AUTOSELECT="YES" for accessibility-focused subtitle tracks.

However, there does appear to be a gap in MediaConvert's capabilities regarding the explicit FORCED attribute for HLS subtitle tracks. While MediaConvert supports DEFAULT and AUTOSELECT attributes for subtitles, the FORCED attribute (which is indeed part of the standard Apple HLS specification) isn't directly configurable in the current MediaConvert options.

For workflows requiring the FORCED attribute, you might need to consider a post-processing approach where you modify the HLS manifest after MediaConvert processing. This isn't ideal compared to having native support in the service.

This limitation is notable given the increasing importance of accessibility features and multilingual content delivery across streaming platforms. Having comprehensive support for all HLS subtitle signaling attributes would better align with industry needs for delivering rich, accessible content.  
**Sources**  
[Back to basics: Accessibility signaling with AWS Elemental Media Services | AWS for M&E Blog](https://aws.amazon.com/blogs/media/back-to-basics-accessibility-signaling-with-aws-elemental-media-services/)  
[Search - AWS Elemental MediaConvert API Reference](https://docs.aws.amazon.com/mediaconvert/latest/apireference/search.html)

Joel · Answer

Ok, I opened a feature request. 
Let hope it will be reviewed soon...

Missing MediaConvert Option for tagging subtitles output tracks FORCED for HLS streams

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