Does Chromecast support TTML?

问题

The Chromecast developer docs say both WebVTT and TTML are Supported Media Types: https://developers.google.com/cast/supported_media_types

I see captions when using a WebVTT file in a "track" tag within a video element:

<video id="vid" src="http://myurl">
    <track kind="captions" src="http://10.16.236.23/test.vtt" srclang="en" label="English" default>
</video>

But when I try to do the same using a valid TTML file, I don't see captions:

<video id="vid" src="http://myurl">
    <track kind="captions" src="test.ttml" srclang="en" label="English" default>
</video>

When I inspect the video element in the debugger console, for the WebVTT example I can see

document.getElementById('vid').textTracks[0].cues.length;

16

but for TTML:

document.getElementById('vid').textTracks[0].cues.length;

0

I am on the right track with this or is TTML supported in a different way? Maybe my TTML syntax is not supported by Chromecast?

回答1:

Unlike webVTT, TTML is not natively supported. If you need to support that in your app, you can simply write a Javascript parser to parse the file and add the cues to your video element in javascript using methods such as addTextTrack(), etc.

回答2:

According to the Cast Player API, Chromecast now supports WebVTT, TTML1, and CEA-608 (Line 21 Captions) caption formats. Just pass in the CaptionsType enum for your caption format into the player's enableCaptions() method.

来源：https://stackoverflow.com/questions/19572313/does-chromecast-support-ttml

标签

google-cast