[gstreamer-bugs] [Bug 349436] New: dvdemux outputs erroneous timestamp/duration when not receiving NEWSEGMENT event

GStreamer (bugzilla.gnome.org) bugzilla-daemon at bugzilla.gnome.org
Mon Jul 31 07:19:08 PDT 2006 

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 GStreamer | gst-plugins-good | Ver: 0.10.x

           Summary: dvdemux outputs erroneous timestamp/duration when not
                    receiving NEWSEGMENT event
           Product: GStreamer
           Version: 0.10.x
          Platform: Other
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: gst-plugins-good
        AssignedTo: gstreamer-bugs at lists.sourceforge.net
        ReportedBy: marcelm at luon.net
         QAContact: gstreamer-bugs at lists.sourceforge.net
     GNOME version: 2.13/2.14
   GNOME milestone: Unspecified


If the dvdemux event does not receive a NEWSEGMENT event prior to receiving
buffers, its output buffers have obviously wrong timestamp/duration fields.

The following pipelines were run with a modified fakesink element that prints
some information (including timestamp and duration) for each buffer it
receives. The lines starting with "chain   *******" are output from fakesink.
Also, the dvdemux element was modified to emit a debug message when it receives
a NEWSEGMENT event.

When using the following pipeline, everything is fine:

gst-launch --gst-debug=dvdemux:5 udpsrc port=8000 ! queue ! rtpdvdepay
queue-delay=0 ! dvdemux ! fakesink

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
DEBUG (0x631fa0 - 0:00:00.062688000)              dvdemux( 7118)
gstdvdemux.c(718):gst_dvdemux_handle_sink_event: NEWSEGMENT received
New clock: GstSystemClock
DEBUG (0x631fa0 - 0:00:04.101093000)              dvdemux( 7118)
gstdvdemux.c(718):gst_dvdemux_handle_sink_event: NEWSEGMENT received
INFO  (0x631fa0 - 0:00:04.101560000)              dvdemux( 7118)
gstdvdemux.c(817):gst_dvdemux_convert_sink_pair: starting conversion of start
DEBUG (0x631fa0 - 0:00:04.101587000)              dvdemux( 7118)
gstdvdemux.c(446):gst_dvdemux_sink_convert:<dvdemux0> 2 -> 3
INFO  (0x631fa0 - 0:00:04.101605000)              dvdemux( 7118)
gstdvdemux.c(448):gst_dvdemux_sink_convert:<dvdemux0> src_value:0,
src_format:2, dest_format:3
INFO  (0x631fa0 - 0:00:04.101625000)              dvdemux( 7118)
gstdvdemux.c(504):gst_dvdemux_sink_convert:<dvdemux0> Result : dest_format:3,
dest_value:0, res:1
INFO  (0x631fa0 - 0:00:04.101641000)              dvdemux( 7118)
gstdvdemux.c(823):gst_dvdemux_convert_sink_pair: Finished conversion of start:
0
INFO  (0x631fa0 - 0:00:04.101664000)              dvdemux( 7118)
gstdvdemux.c(825):gst_dvdemux_convert_sink_pair: starting conversion of stop
DEBUG (0x631fa0 - 0:00:04.101681000)              dvdemux( 7118)
gstdvdemux.c(446):gst_dvdemux_sink_convert:<dvdemux0> 2 -> 3
INFO  (0x631fa0 - 0:00:04.101697000)              dvdemux( 7118)
gstdvdemux.c(448):gst_dvdemux_sink_convert:<dvdemux0> src_value:-1,
src_format:2, dest_format:3
INFO  (0x631fa0 - 0:00:04.101714000)              dvdemux( 7118)
gstdvdemux.c(832):gst_dvdemux_convert_sink_pair: Finished conversion of stop:
-1
INFO  (0x631fa0 - 0:00:04.101731000)              dvdemux( 7118)
gstdvdemux.c(344):gst_dvdemux_src_convert:<dvdemux0:video> src_value:0,
src_format:3, dest_format:1
INFO  (0x631fa0 - 0:00:04.101748000)              dvdemux( 7118)
gstdvdemux.c(429):gst_dvdemux_src_convert:<dvdemux0:video> Result :
dest_format:1, dest_value:0, res:1
DEBUG (0x631fa0 - 0:00:04.101766000)              dvdemux( 7118)
gstdvdemux.c(1363):gst_dvdemux_demux_frame:<dvdemux0> sending segment start:
0:00:00.000000000, stop: 99:99:99.999999999, time: 0:00:00.000000000
DEBUG (0x631fa0 - 0:00:04.101873000)              dvdemux( 7118)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 0:00:00.000000000
DEBUG (0x631fa0 - 0:00:04.101908000)              dvdemux( 7118)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 0:00:00.000000000
chain   ******* < (144000 bytes, timestamp: 0:00:00.000000000, duration:
0:00:00.040000000, offset: 0, offset_end: 1, flags: 0) 0x63d130
DEBUG (0x631fa0 - 0:00:04.140799000)              dvdemux( 7118)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 0:00:00.040000000
DEBUG (0x631fa0 - 0:00:04.140850000)              dvdemux( 7118)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 0:00:00.040000000
chain   ******* < (144000 bytes, timestamp: 0:00:00.040000000, duration:
0:00:00.040000000, offset: 1, offset_end: 2, flags: 0) 0x63d2b0
DEBUG (0x631fa0 - 0:00:04.181543000)              dvdemux( 7118)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 0:00:00.080000000
DEBUG (0x631fa0 - 0:00:04.181591000)              dvdemux( 7118)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 0:00:00.080000000
chain   ******* < (144000 bytes, timestamp: 0:00:00.080000000, duration:
0:00:00.040000000, offset: 2, offset_end: 3, flags: 0) 0x63d430
DEBUG (0x631fa0 - 0:00:04.221018000)              dvdemux( 7118)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 0:00:00.120000000
DEBUG (0x631fa0 - 0:00:04.221065000)              dvdemux( 7118)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 0:00:00.120000000
chain   ******* < (144000 bytes, timestamp: 0:00:00.120000000, duration:
0:00:00.040000000, offset: 3, offset_end: 4, flags: 0) 0x63d5b0
DEBUG (0x631fa0 - 0:00:04.261802000)              dvdemux( 7118)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 0:00:00.160000000
DEBUG (0x631fa0 - 0:00:04.261850000)              dvdemux( 7118)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 0:00:00.160000000
chain   ******* < (144000 bytes, timestamp: 0:00:00.160000000, duration:
0:00:00.040000000, offset: 4, offset_end: 5, flags: 0) 0x63d4b0
...

Note that each buffer received by fakesink has a duration of 0.04 seconds, and
a monotonically increasing timestamp.

When we add the rtpdemux element (which doesn't seem to forward NEWSEGMENT
events), we get the following pipeline:

gst-launch --gst-debug=dvdemux:5 udpsrc port=8000 ! queue ! rtpdemux !
rtpdvdepay queue-delay=0 ! dvdemux ! fakesink

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
DEBUG (0x639fc0 - 0:00:02.746882000)              dvdemux( 7157)
gstdvdemux.c(718):gst_dvdemux_handle_sink_event: NEWSEGMENT received
DEBUG (0x639fc0 - 0:00:02.747391000)              dvdemux( 7157)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 103:44:20.343500000
DEBUG (0x639fc0 - 0:00:02.747438000)              dvdemux( 7157)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 103:44:20.343500000
chain   ******* < (144000 bytes, timestamp: 103:44:20.343500000, duration:
5123991:50:13.406051616, offset: 0, offset_end: 1, flags: 0) 0x641120
DEBUG (0x639fc0 - 0:00:02.786584000)              dvdemux( 7157)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 103:44:20.343500000
DEBUG (0x639fc0 - 0:00:02.786632000)              dvdemux( 7157)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 103:44:20.343500000
chain   ******* < (144000 bytes, timestamp: 103:44:20.343500000, duration:
5123991:50:13.446051616, offset: 1, offset_end: 2, flags: 0) 0x6412a0
DEBUG (0x639fc0 - 0:00:02.827162000)              dvdemux( 7157)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 103:44:20.343500000
DEBUG (0x639fc0 - 0:00:02.827214000)              dvdemux( 7157)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 103:44:20.343500000
chain   ******* < (144000 bytes, timestamp: 103:44:20.343500000, duration:
5123991:50:13.486051616, offset: 2, offset_end: 3, flags: 0) 0x641420
DEBUG (0x639fc0 - 0:00:02.866789000)              dvdemux( 7157)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 103:44:20.343500000
DEBUG (0x639fc0 - 0:00:02.866837000)              dvdemux( 7157)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 103:44:20.343500000
chain   ******* < (144000 bytes, timestamp: 103:44:20.343500000, duration:
5123991:50:13.526051616, offset: 3, offset_end: 4, flags: 0) 0x6415a0
DEBUG (0x639fc0 - 0:00:02.907381000)              dvdemux( 7157)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 103:44:20.343500000
DEBUG (0x639fc0 - 0:00:02.907424000)              dvdemux( 7157)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 103:44:20.343500000
chain   ******* < (144000 bytes, timestamp: 103:44:20.343500000, duration:
5123991:50:13.566051616, offset: 4, offset_end: 5, flags: 0) 0x6414a0
DEBUG (0x639fc0 - 0:00:02.946920000)              dvdemux( 7157)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 103:44:20.343500000
DEBUG (0x639fc0 - 0:00:02.946964000)              dvdemux( 7157)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 103:44:20.343500000
chain   ******* < (144000 bytes, timestamp: 103:44:20.343500000, duration:
5123991:50:13.606051616, offset: 5, offset_end: 6, flags: 0) 0x641320
DEBUG (0x639fc0 - 0:00:02.986617000)              dvdemux( 7157)
gstdvdemux.c(1234):gst_dvdemux_demux_audio: pushing audio 103:44:20.343500000
DEBUG (0x639fc0 - 0:00:02.986668000)              dvdemux( 7157)
gstdvdemux.c(1317):gst_dvdemux_demux_video: pushing video 103:44:20.343500000
chain   ******* < (144000 bytes, timestamp: 103:44:20.343500000, duration:
5123991:50:13.646051616, offset: 6, offset_end: 7, flags: 0) 0x6411a0

Note how each buffer received by fakesink has the same timestamp as the
previous buffer, but the duration (which is obviously wrong anyway) is
increasing.


I've looked through the source briefly. It seems that GstDVDemux->need_segment
is initialized to FALSE, and set to TRUE on receiving a NEWSEGMENT event.
Apparantly, timestamp administration is initialized properly when need_segment
is TRUE, so when need_segment never is TRUE because of a lack of a NEWSEGMENT
event, the timestamping goes wacko.

If dvdemux cannot operate without receiving a NEWSEGMENT event, it should throw
an error, rather than failing silently as it does now.


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