Legacy players, e.g. older versions of ExoPlayer, do not handle default webvtt text alignment correctly. Need to specify `align:center` explicitly cues without text alignment for backwards compatibility.
Fixes#925.
Now text-based WebVTT also uses the generic media pipeline. This
converts the WebVttTextOutputHandler to a WebVttMuxer to be more
consistent with the other muxer types.
This also allows choosing between single-segment text and multi-segment.
Before, we would generate both and use single-segment for DASH and
multi-segment for HLS; but now you can choose between either and either
are supported in both DASH and HLS.
Change-Id: I6f7edda09e01b5f40e819290d3fe6e88677018d9
Note that TTML in ISO-BMFF is not supported yet.
Also updated packager_test.py:
- Added a test using TTML passthrough.
- Computed output extension from input extension unless output_format
is specified.
Fixes#478.
Change-Id: Ia917fc4ed3c326782791ed67601fba02ea28b11d
Vishal Shah
Jacob Trimble
KongQun Yang