It turns out that, on some browsers, incomplete XML does not properly
parse. This means the parseFirstCue tests did not work on those platforms.
This modifies those tests on platforms that do not support partial XML;
when no support is detected, it instead tries to get the first cue
from a non-partial segment.
This also modifies the HLS parser to only load partial text segments if
the text parser supports it; otherwise, the hls parser will load full
captions in order to extract start times.
b/137945635
Issue #2037
Change-Id: I58112864a818baf155b365a65fba1c8a56eb9520
Previously, when the text engine tried to load the start time of
a segment, it would parse every cue in that segment, then check the
time of the first cue. This was judged to not be a significant
performance issue, as parsing cues is a fast operation. However, it
did have an unintended side-effect: in some situations, this method
was being passed partial segments; notably, the HLS parser would load
the first 2048kb of the stream's texts to extract timing data.
If the caption parsers tried to actually parse an incomplete caption,
they would error.
This gives the text parsers "parseFirstCue" methods, and uses those
methods when it only needs the first cue anyway.
Fixes#2037
Change-Id: I2a1fb2f1a96d98967f0c6e6a5c277914a28b42ad
This is an automated change to convert use of "function" functions
to arrow functions. This doesn't change all uses of bind() that
could be converted. This also doesn't remove all "function" functions.
Change-Id: I40ac7d086bcef947a1be083359c8fd1d4499a9c3
This is part of a change to convert all usages of 'var' with either
'let' or 'const'. This takes a conservative approach for 'const' where
it will only be used for aliases and storing the "original" values in
tests.
Change-Id: I6a329d28e13a81c9f7136737518c6bb8fa18402e
This speeds up HLS stream startup significantly for servers that
permit this kind of request, and falls back to full segments for
servers that do not.
Closes#1106
Change-Id: I96bc7f0df0fb84b75f3a3fe43476ba0ba5fc2264
This converts from using ArrayBuffer in the text parsers to using
Uint8Array. This avoids doing extra buffer copies when using
ArrayBuffer.slice().
Closes#1022
Change-Id: I34a789ec4eb76c95169ba81f27a8433ef25f27f0
Beforehand, if we were parsing a ttml subtitles stored in an mp4, we did
not account for the possibility that there would be multiple mdat boxes,
each with its own ttml data. In such a case, we would only use the
payload from the final mdat.
I don't know if having multiple mdat like that is really in the spec, but
at least one user has had this problem, and it's a straightforward change
to make that doesn't really slow down the text parser at all (since we
parse every mdat anyway).
Closes#1028
Change-Id: Id782695548cb92f7aa7278843695b670d8c15ff0
Previously, our HLS implementation only supported WebVTT, because
that seemed to be the only supported format in HLS.
Now, we add support for other formats by extending the MIME and codec
guessing system to text streams. We also add a parser registration
for HLS's new "stpp.TTML.im1t" codec string.
Closes#986
Change-Id: I0a58ca4650675ff0546e36edf4114290f7931239
This change creates a lib/text directory and moves all files
with text-related logic to it. It also lays the ground for
separating text parsing and display logic. (That change will
introduce even more files with text-related logic which will
crowd lib/media directory).
Issue #796.
Change-Id: I65ac134020a0126ff02a8f2067beb73870232e65
Theodore Abshire
Jacob Trimble
Joey Parrish
Sandra Lokshina