It is not always possible to align segment duration to target duration
exactly. For example, for AAC with sampling rate of 44100, there are
always 1024 audio frames per sample, so the sample duration is
1024/44100. For a target duration of 2 seconds, the closest segment
duration would be 1.984 or 2.00533.
This feature allows MPD generator to treat these segments as having
the same duration, thus allows MPD generator to generate less
SegmentTimeline entries and potentially no SegmentTimeline entries
(replaced with SegmentTemplate@duration instead if
--segment_template_constant_duration flag is enabled).
Under flag --allow_approximate_segment_timeline. Disabled by default.
Fixes#330.
Change-Id: I5044eaa348ebbf45bf792a2af53fc95a115ae21b
Removed the logic in MuxerListener to estimate bandwidth from file
size and duration, since it is not compliant to the spec.
MpdBuilder will estimate bandwidth from segment size and duration
if bandwidth is not specified in MediaInfo.
Here is the statement from 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.
Fixes#376.
Change-Id: I0fddce39e709d0cded0a4c9ae59adbbcc97ec5ea
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
This flag was introduced to workaround a rounding error in Chrome
(probably in other browsers too).
Also although this flag avoids the first frame of a Period to be
dropped due to rounding error but it could cause the last frame of a
Period to be dropped.
Now that we use a high precision Period@duration, we do not expect to
see rounding errors any more. The player would be a better place for
the workaround even if it is still needed.
Related issue: #368.
Change-Id: I3bd517ecc6d548ff62e0c13394edb49d4bc68e8f
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
This change has the hls master playlist add the text codec string
to the list of codecs in a variant.
Bug: 72942756
Change-Id: Ib25bb2064a291d10d7b1d261a4307991df62220c
Also added Period::GetAdaptationSets and
AdaptationSet::GetRepresentations.
Instead of implementing GetDurationSeconds in all MpdBuilder classes
(MpdBuilder/Period/Adaptation/Representation) like what we used to do
with GetEarliestTimestamp, the two new functions allows MpdBuilder to
iterate through the Representations to get durations.
Also updates GetEarliestTimestamp functions to use the same iteration
method.
Change-Id: I682b70c07c248c0f6511ec3d9019086f986ee10e
Move AdaptationSet related functions to the new Period class, which
maps to <Period> element and provides methods to add AdaptationSets.
Change-Id: I0fee290769fbe9a6355cc1b8c86baec8fbc4b4fd
KongQun Yang
Aaron Vaage