[Bug 705679] New: dashdemux: faulty buffer timestamps when using SegmentTemplate element

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=705679
  GStreamer | gst-plugins-bad | git

           Summary: dashdemux: faulty buffer timestamps when using
                    SegmentTemplate element
    Classification: Platform
           Product: GStreamer
           Version: git
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: gst-plugins-bad
        AssignedTo: gstreamer-bugs at lists.freedesktop.org
        ReportedBy: floobleflam at gmail.com
         QAContact: gstreamer-bugs at lists.freedesktop.org
     GNOME version: ---


Created an attachment (id=251187)
 View: https://bugzilla.gnome.org/attachment.cgi?id=251187
 Review: https://bugzilla.gnome.org/review?bug=705679&attachment=251187

Patch to remove incorrect timestamp scaling

When using a SegmentTemplate element, the timestamps of the buffers output by
dashdemux are incorrect, causing problems downstream.

The reason is that GstMediaSegment start times are calculated (in
gst_mpdparser_get_chunk_by_index) by multiplying segment index by segment
duration and then scaling the result according the `timebase' attribute from
the MPD. However, the segment duration is already a GstClockTime (i.e., it has
already been scaled according to the timebase from the MPD and converted to a
nanosecond value), so multiplying it by the segment index will give the correct
timestamp without the need for any further scaling; and, hence, scaling it
using timebase will result in an incorrect timestamp.

Patch to fix this issue is attached.

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