[gstreamer-bugs] [Bug 575972] New: [GnlComposition] Switch to using regular segment seeks instead of GST_SEEK_FLAG_SEGMENT

[GStreamer (bugzilla.gnome.org)]

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  GStreamer | gnonlin | Ver: git
           Summary: [GnlComposition] Switch to using regular segment seeks
                    instead of GST_SEEK_FLAG_SEGMENT
           Product: GStreamer
           Version: git
          Platform: Other
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: gnonlin
        AssignedTo: gstreamer-bugs at lists.sourceforge.net
        ReportedBy: bilboed at gmail.com
         QAContact: bilboed at gmail.com
     GNOME version: Unspecified
   GNOME milestone: Unspecified


Currently in GnlComposition, we rely entirely on GST_MESSAGE_SEGMENT_DONE to
know when objects have finished processing the current segment.

The problem is that we might have queues in the give objects/sources/operations
after the element driving the pipeline (like a demuxer or a basesource
element).

This results in the composition receiving the message *before* that given
source/operation has actually pushed out all the buffers/tags/events for that
given segment. This effect is even worse with gnlfilesource (using decodebin(2)
internally) to such a point that for some short files the message will be
received before *any* buffers are outputted.

The proposal is therefore to replace the seeks that GnlComposition is sending
to the contained objects by:
* *NOT* setting the GST_SEEK_FLAG_SEGMENT flag
* putting even_probes on top-level source pads which, when they see EOS events,
discard them and informs the composition
* once all EOS have been received, call update_pipeline with the
segment->start.


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