A realtime clock is used in many places, such as deciding which
fragment to select at start up and deciding how long to sleep
before a fragment becomes available. For example dashdemux needs
sample the client's estimate of UTC when selecting where to start
in a live DASH stream.
The problem with dashdemux calculating the client's idea of UTC is
that it makes it difficult to create unit tests, because the passage
of time is a factor in the test.
This commit changes dashdemux and adaptivedemux to use the
GstSystemClock, so that a unit test can replace the system clock when
it needs to be able to control the clock.
This commit makes no change to the behaviour under normal usage, as
GstSystemClock is based upon the system time.
https://bugzilla.gnome.org/show_bug.cgi?id=762147
The code in the gst_dash_demux_parse_http_xsdate() was trying to
handle the case where the string is not null terminated by resizing
the buffer and appending a zero byte. This does not work if the buffer
is exactly the length of the string because the gst_buffer_resize()
function does not re-allocate the buffer, it just changes its size.
If a buffer is passed to gst_dash_demux_parse_http_xsdate() that is
exactly the length of the string, the function fails with an assert
failure in gst_buffer_resize().
https://bugzilla.gnome.org/show_bug.cgi?id=762148
The function actually returns the segment availability start time (as defined by the standard).
That is at the end of the segment, but it is called availability start time.
Availability end time is something else (the time when the segment is no longer
available on the server). The function name was misleading.
https://bugzilla.gnome.org/show_bug.cgi?id=757655
Adaptive demuxers need to start downloading from specific positions
(fragments) for every stream, this means that all streams can snap-seek
to a different position when requested. Snap seeking in this case will
be done in 2 steps:
1) do the snap seeking on the pad that received the seek event and
get the final position
2) use this position to do a regular seek on the other streams to
make sure they all start from the same position
More arguments were added to the stream_seek function, allowing better control
of how seeking is done. Knowing the flags and the playback direction allows
subclasses to handle snap-seeking.
And also adds a new return parameter to inform of the final
selected seeking position that is used to align the other streams.
https://bugzilla.gnome.org/show_bug.cgi?id=759158
For a live mpd, if availabilityStartTime is missing, adaptive demux asserts
with: Unexpected critical/warning: gst_date_time_to_g_date_time: assertion
'datetime != NULL' failed.
This patch improves the error message to:
Unexpected critical/warning: gst_mpd_client_seek_to_time: assertion
'client->mpd_node->availabilityStartTime != NULL' failed
https://bugzilla.gnome.org/show_bug.cgi?id=757602
Handling the ghostpad and its internal pad was causing more issues
than helping because of their coupled activation/deactivation
actions.
As we have to install custom chain,event and query functions it is
better to use a floating sink pad internally in the demuxer and just
use those pad functions to push through a standard pad in the demuxer
https://bugzilla.gnome.org/show_bug.cgi?id=757951
gst_mpdparser_parse_utctiming_node does not validate the parsed values completely. The following scenarios are incorrectly accepted:
- elements with no schemeIdUri property should be rejected
- elements with unrecognized UTCTiming scheme should be rejected
- elements with empty values should be rejected
The last one triggers a division by 0 in gst_dash_demux_poll_clock_drift:
clock_drift->selected_url = clock_drift->selected_url % g_strv_length (urls);
because it urls is a valid pointer to an empty array.
https://bugzilla.gnome.org/show_bug.cgi?id=759547
Dashdemux has set the width and height information from MPD manifest.
Some embedded devices which are not insufficient H/W resources need more information such as framerate
to assign H/W resources. So I suggested that dashdemux also needs to set the framerate information from MDP manifest.
https://bugzilla.gnome.org/show_bug.cgi?id=758515
The stream->cur_seg_template is set to the lowest available segment
template (representation or adaptation or period, in this order).
Because the template elements are inherited, the lowest template will
have all the elements the parents had, so there is no need to check the
parent for an element that is not found in the child (eg initialisation
or index).
https://bugzilla.gnome.org/show_bug.cgi?id=752714
The standard does not seem to make any particular explicit not
implicit reference to the signedness of durations, and the code
does not rely on such, nor on the negativity of the -1 value
that's used as a placeholder when a duration property is not
present in the XML.
https://bugzilla.gnome.org/show_bug.cgi?id=750847
According to the standard:
"SegmentBase, SegmentTemplate and SegmentList shall inherit
attributes and elements from the same element on a higher level.
If the same attribute or element is present on both levels,
the one on the lower level shall take precedence over the one
on the higher level."
gst_mpdparser_parse_segment_list_node will now discard any inherited
segment URLs if the parsed element defines some too.
https://bugzilla.gnome.org/show_bug.cgi?id=751832
If MPD@suggestedPresentationDelay is not present in the manifest,
dashdemux selects the fragment closest to the most recently generated
fragment. This causes a playback issue because this choice does not allow
the DASH client to build up any buffer of downloaded fragments without
pausing playback. This is because by definition new fragments appear on
the server in real-time (e.g. if segment duration is 4 seconds, a new
fragment will appear on the server every 4 seconds). If the starting
playback position was n*segmentDuration seconds behind "now", the DASH
client could download up to 'n' fragments faster than realtime before it
reached the point where it needed to wait for fragments to appear on the
server.
The MPD@suggestedPresentationDelay attribute allows a content publisher
to provide a suggested starting position that is behind the current
"live" position.
If the MPD@suggestedPresentationDelay attribute is not present, provide
a suitable default value as a property of the dashdemux element. To
allow the default presentation delay to be specified either using
fragments or seconds, the property is a string that contains a number
and a unit (e.g. "10 seconds", "4 fragments", "2500ms").
Corrected the parsing of a segment template string.
Added unit tests to test the segment template parsing.
All reported problems are now correctly handled.
https://bugzilla.gnome.org/show_bug.cgi?id=751735
When building the media segment list using a SegmentList node, the
gst_mpd_client_setup_representation function will iterate through the
list of S nodes and will expect to find a matching SegmentUrl node. If
one does not exist, the code made an illegal memory access.
https://bugzilla.gnome.org/show_bug.cgi?id=752496
These are used to apply restrictions on what the MPD file may
use, so no profile means no restrictions.
Besides, nothing actually uses the profiles (yet) anyway.
https://bugzilla.gnome.org/show_bug.cgi?id=750869
