This only supports TTML output; meaning the user can convert WebVTT
into TTML, but not the other way around. This will be useful for
DVB-sub subtitles that would be better supported within TTML.
This only adds text-based output; a follow-up will add MP4 support.
Change-Id: I0944b7df95d7765e55f203fc5e9a644f5c455dd8
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
Jacob Trimble