- I think \r and \n are handled the wrong way around?
- We only expect to encounter a BOM sequence at the start of a
file, but it feels fine to automatically discard it in all
cases for simplicity. A BOM sequence doesn't mean anything in
UTF-8. See https://en.wikipedia.org/wiki/Byte_order_mark. Note
that I think the advice not to remove it on that page relates
only to the case where the file is being edited + saved.
Issue #1136
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=112143407
Moved the behaviors related to Cue's to the WebvttCueParser class.
This way, the parsing methods will be more easily accessible to
other classes, such as the MP4Webvtt parser. This class also has
some methods that require state to avoid repetitive avoidable
allocations. The method visibility is subject to changes in
further CLs.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=111616824
This CL is prepares the ground for refactoring the Webvtt parser,
so as to use the common parsing algorithms in both parsers. In order
to do this, the Webvtt Parser will be refactored. As a side note, many
more test cases will be added once the new subtitle features are
implemented. Some useful test cases have also been left for a following
CL, to allow an easy code review.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=110466914
- parse webvtt cue
- remove all tags from string (supported or not)
- apply spans for b, i and u
- honor class names in tags to properly parse the cue but do not apply styles for them
* Split findNextCueHeader and validateWebVttHeader into static methods.
This is a step toward WebVTT in HLS, where we'll need to re-use these
to peek at the top of the WebVTT file (they'll be moved into a util
class).
* Made parser robust against bad cue headers + added a test.
* Removed spurious looking assertion in WebvttSubtitle.
They don't seem particularly useful; they don't technically force
strict compliance, but rather just catch a few token things in
each case. Furthermore, for playback, probably the right thing to
do is to always turn strict mode off.
- Line parameter
- Added support for value and line alignment attributes.
- Support negative numbers when line is an absolute number (not a
percentage).
- Position parameter
- Added support for value and position alignment attributes
- Added support for WebVTT comment blocks
- Percentage values now accept decimal numbers (as webvtt spec states)
- Added new WebVTT tests for testing all new implemented features
- do not denormalize styles at parsing time but only put normalized style info
into TtmlNode tree. Resolve styles on demand when Cues are requested for a
given timeUs.
- create TtmlRenderUtil to have static render functions separate
- added unit test for TtmlRenderUtil
- adjusted testing strategy for unit test to check resolved style on Spannables after rendering
- Remove unused method in DashChunkSource.
- Remove inputEncoding parameter for subtitle parsers. We're
ignoring it in all but one of the parsers, and for the one
that does use it, it'll only ever receive null, since that's
all we're passing.
- Make TextTrackRenderer advance to the next subtitle even if
the current one hasn't finished, in the case that they overlap.
This shouldn't ever really happen, but it seems best to trust
the start time of the new sample rather than the last event
time of the previous one.
- Currently all subtitles we parse contain timestamps relative to the sample
timestamp, however we add the sample timestamp in inconsistent ways (sometimes
in the Subtitle, sometimes in the SubtitleParser). This change converges on
a single approach. It also paves the way for passing absolute offsets to use
instead, and being able to apply them in a consistent way in a single place
(PlayableSubtitle). This functionality will be required for ISO 14496-30 TTML
embedded subtitles.
Issue: #689
