According to the HLS+WebVTT spec, if there is no text in a segment
a webvtt file with no cues can be added to the manifest. By outputting
empty segments it allows the accumulated duration in the Master Playlist
to better represent the duration of the text stream.
Spec Reference: //tools.ietf.org/html/draft-pantos-http-live-streaming-23
Section 3.5. WebVTT
Bug: #205
Change-Id: I5de01200fd9fa99c57949c773e8ee926b0f6ba8a
To better align with the Chunking Handler, the Text Segmenter
now outputs the SegmentInfo at the end of the segment rather
than the start.
Change-Id: If69ab951947d00779b4b63a52c4b6662bbdc4c0d
This change creates the webvtt segmenter which will be used for
segmented text webvtt for HLS. It takes a stream of text samples
and injects segment info messages based on the segment duration.
It is possible for samples to extend between segments, if so the
sample will appear twice (once in each segment).
Change-Id: Iae0134ee61cf269948026086520b6d3f8ce3785b
Aaron Vaage