- EditLists in input files are parsed and applied to sample timestamps.
- An EditList will be inserted in the ISO-BMFF output if
- There is an offset between the initial presentation timestamp (pts)
and decoding timestamp (dts). Chrome, as of M67, still uses dts in
buffered range API [1], which creates various problems when buffered
range by pts does not align with buffered range by dts. There is
another bug in Chrome that applies EditList to pts only [2]. This
means that we can insert an EditList to align pts range and dts range.
- MediaSamples have negative timestamps (e.g. for Audio Priming).
You may notice the below change on some contents:
- Some media duration is reduced by one or two frames. This is because
EditList in the input file was ignored in the previous code, so video
streams start with a zero dts and a non-zero pts; the smaller of dts
and pts was used as the starting timestamp (related to the earlier
workaround for Chrome's dts bug), so the calculated duration was
actually a bit larger than the actual duration. Now with EditList
applied, the initial pts is reduced to zero, so the media duration is
also reduced to reflect the actual and correct media duration.
It may also result in negative timestamps in TS/HLS Packed Audio, which
will be addressed in a follow up CL.
Fixes#112.
Partially address b/110782437.
[1] https://crbug.com/718641, fixed but behind MseBufferByPts.
[2] https://crbug.com/354518. Chrome is planning to enable the fix for
[1] before addressing this bug, so we are safe.
Change-Id: I59317740ad3807ca66fa74b3a18fdf7f32c96aeb
According to DASH spec (23009-1:2014):
Consider a hypothetical constant bitrate channel of
bandwidth with the value of this attribute in bits per second
(bps). Then, if the Representation is continuously delivered
at this bitrate, starting at any SAP that is indicated either by
@startwithsap or by any Segment Index box, a client can
be assured of having enough data for continuous playout
providing playout begins after @minbuffertime *
@bandwidth bits have been received (i.e. at time
@minbuffertime after the first bit is received).
For dependent Representations this value specifies the
bandwidth according to the above definition for the
aggregation of this Representation and all complementary
Representations.
This suggests that max bitrate should be used instead of average
bitrate.
Also cleaned up BandwidthEstimator code.
Fixes#376.
Change-Id: Ibf5896394c5c6bb820849771a2129c59202d2273
Instead, the actual earliest presentation time is used except for
the first segment if there is an offset between presentation time
(pts) and decoding time (dts).
Chrome (as of v66) reports dts instead of pts in buffered ranges in
MSE API. To avoid breaking Chrome, the earliest_presentation_time
of the first segment is set to its dts as Chrome does not like negative
values for
adjusted dts = dts + Period@start (0 for the first period)
- presentationTimeOffset (earliest_presentation_time).
Fixes#303.
Change-Id: I5ca80e05d5570961400499436f2bcc01f06e69e0
Chrome internally uses time accurate to microseconds, which is
implemented per MSE spec (https://www.w3.org/TR/media-source/).
Generate Period@duration with better precision to avoid possible
buffered range gaps in Chrome (possibly other browsers too), which
may lead to other problems like playback stall.
b/74238961
Fixes#368.
Change-Id: I357a0f62b67f75c7ca044bb99ea4e3c8bbb6fecd
Instead of using the test file's index in a list to create the output
name, use the original filename and the descriptor.
This caused some problems with file name collisions when some tests
were using the same name. That was fixed by changing the names. This
will go away once they are transitioned to use DiffDir like the other
tests.
Change-Id: I0a4c480406705ca63fcea61c86c67d4a5f739295
Prefer timestamps from Video AdaptationSets if available - this avoids
possible video playback jitters due to gaps.
presentationTimeOffset is not applied to the first period as it may in
negative dts which Chrome does not like: https://crbug.com/398141.
It is safe to apply to subsequent periods as the actual offset applied
takes Period@start into consideration:
offset = Period@start - presentationTimeOffset
The result timestamp with offset applied is close to Period@start, so
it is unlikely to result in a negative dts value.
Closes b/73899306.
Change-Id: If8361f5469610093b3aac6675754536ad7e83c4c
KongQun Yang
Aaron Vaage