[gstreamer-bugs] [Bug 614612] New: cairotextoverlay causes pipe stalls in cases where textoverlay does not

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=614612
  GStreamer | gst-plugins-good | 0.10.28

           Summary: cairotextoverlay causes pipe stalls in cases where
                    textoverlay does not
    Classification: Desktop
           Product: GStreamer
           Version: 0.10.28
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: gst-plugins-good
        AssignedTo: gstreamer-bugs at lists.sourceforge.net
        ReportedBy: divVerent at alientrap.org
         QAContact: gstreamer-bugs at lists.sourceforge.net
      GNOME target: ---
     GNOME version: ---


When encoding videos from MKV to MP4 for my Blackberry using gst-launch, I
ended up with trouble regarding subtitle rendering:
- textoverlay can word-wrap, but looks ugly (no anti aliasing)
- cairotextoverlay looks good, but cannot word wrap, and, which is the focus of
this report, stalls the pipeline whatever I try.

An example video (released online by the Chaos Computer Club Cologne, subtitles
by me) can be found at
http://rm.endoftheinternet.org/~nexuiz/gst-cairotextoverlay-hang/

The includes shell script, if called with the argument "fail", performs:

gst-launch \
   filesrc location="17.mkv" ! matroskademux name=demuxer \
   demuxer.subtitle_00 ! queue ! sub. \
   demuxer.video_00 ! queue ! decodebin ! queue ! cairotextoverlay name=sub !
queue ! xvimagesink sync=false

The pipeline will hang (i.e. playback wills top) at the first line of subtitles
(in what I ACTUALLY want to encode, I get that hang only after about 20 seconds
of input).

If cairotextoverlay is replaced by textoverlay, the pipeline does NOT stall and
playback continues up to the end.

If the filesrc is doubled, it seems to not stall - the video plays indeed back
to the end - but then gst-launch does not exit. The "last words" with added -v
-m are:

Got message #4883 from element "pipeline0" (eos): no message details
Got EOS from element "pipeline0".
Execution ended after 72374852699 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
/GstPipeline:pipeline0/GstXvImageSink:xvimagesink0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue3.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue3.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstCairoTextOverlay:sub.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstCairoTextOverlay:sub.GstPad:text_sink: caps = NULL
/GstPipeline:pipeline0/GstCairoTextOverlay:sub.GstPad:video_sink: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue0.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue0.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue2.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue2.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstMatroskaDemux:demuxer2.GstPad:subtitle_00: caps =
NULL
/GstPipeline:pipeline0/GstMatroskaDemux:demuxer2.GstPad:audio_00: caps = NULL
/GstPipeline:pipeline0/GstMatroskaDemux:demuxer2.GstPad:video_00: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:src0: caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_h264:ffdec_h2640.GstPad:src:
caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/ffdec_h264:ffdec_h2640.GstPad:sink:
caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:src:
caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0/GstTypeFindElement:typefind.GstPad:sink:
caps = NULL
/GstPipeline:pipeline0/GstDecodeBin:decodebin0.GstGhostPad:sink: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue1.GstPad:src: caps = NULL
/GstPipeline:pipeline0/GstQueue:queue1.GstPad:sink: caps = NULL
/GstPipeline:pipeline0/GstMatroskaDemux:demuxer.GstPad:subtitle_00: caps = NULL
/GstPipeline:pipeline0/GstMatroskaDemux:demuxer.GstPad:audio_00: caps = NULL
/GstPipeline:pipeline0/GstMatroskaDemux:demuxer.GstPad:video_00: caps = NULL
Setting pipeline to NULL ...
Freeing pipeline ...

gst-launch \
        filesrc location="17.mkv" ! matroskademux name=demuxer \
        filesrc location="17.mkv" ! matroskademux name=demuxer2 \
        demuxer2.subtitle_00 ! queue ! sub. \
        demuxer.video_00 ! queue ! decodebin ! queue ! cairotextoverlay
name=sub ! queue ! xvimagesink sync=false

Any idea whether this is a) a bug in cairotextoverlay, or b) in my command
line, and in case of b), how I can fix it?

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