[gstreamer-bugs] [Bug 577288] New: "Internal playbin error" when seeking to the end of files

[GStreamer (bugzilla.gnome.org)]

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  GStreamer | gst-plugins-base | Ver: 0.10.22
           Summary: "Internal playbin error" when seeking to the end of
                    files
           Product: GStreamer
           Version: 0.10.22
          Platform: Other
        OS/Version: All
            Status: UNCONFIRMED
          Severity: minor
          Priority: Normal
         Component: gst-plugins-base
        AssignedTo: gstreamer-bugs at lists.sourceforge.net
        ReportedBy: csaba.kos at gmail.com
         QAContact: gstreamer-bugs at lists.sourceforge.net
     GNOME version: Unspecified
   GNOME milestone: Unspecified


DESCRIPTION:
When using "Songbird 1.1.1" on Mac/Linux/Win32, seeking to the end of a song
using the seek bar sometimes results in an error message: "Internal playbin
error."

******** Relevant log output ********
playbin2 gstplaybin2.c:1910:no_more_pads_cb:<player> no more pads in group
0x938ae0

(<unknown>:21033): GStreamer-CRITICAL **: gst_ghost_pad_new: assertion
`!gst_pad_is_linked (target)' failed

(<unknown>:21033): GStreamer-CRITICAL **: gst_pad_link_prepare: assertion
`GST_IS_PAD (sinkpad)' failed
playbin2 gstplaybin2.c:1925:no_more_pads_cb:<player> linked type audio/x-raw-,
result: -6
playbin2 gstplaybin2.c:1929:no_more_pads_cb:<player> error: Internal playbin
error.
playbin2 gstplaybin2.c:1929:no_more_pads_cb:<player> error: Failed to link
selector to sink. Error -6
******** Relevant log output ********


POSSIBLE REASON:
I'm a beginner to gstreamer, but it seems to me that the problem might be the
following:
1. In gstplaysink.c (from gst-plugins-base 0.10.22, lines 1532-1546), an
"audiotee" element is created lazily.
2. After that, a ghost pad is created (lines 1547-1552):
 playsink->audio_pad =
            gst_ghost_pad_new ("audio_sink", playsink->audio_tee_sink);
3. At some point, the ghost pad is released in gst_play_sink_release_pad()
(lines 1592-1615).
4. Next time when a ghost pad is created in step 2 above, the
"playsink->audio_tee_sink" element is still linked to some other element,
therefore gst_ghost_pad_new() asserts and fails.

So in short, the problem seems to be that no one unlinks the audio_tee_sink
element from its peer.



SUGGESTION:
Unlink the audio_tee_sink element in gst_play_sink_release_pad(). For example,
add the following line to gstplaysink.c (line 1603):
gst_pad_unlink(playsink->audio_tee_sink->peer, playsink->audio_tee_sink);

So that it will look like;
  } else if (pad == playsink->audio_pad) {
    res = &playsink->audio_pad;
    gst_pad_unlink(playsink->audio_tee_sink->peer, playsink->audio_tee_sink);
// line 1603
  } else if (pad == playsink->text_pad) {

This solves the problem for me, and it seems that it does not introduce any
other problems.


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