Bug 553755 – [mpegpsdemux] FP exception when playing tv2-1_25.mpg

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Bug 553755 - [mpegpsdemux] FP exception when playing tv2-1_25.mpg


Summary:	[mpegpsdemux] FP exception when playing tv2-1_25.mpg


Status:	RESOLVED FIXED

Product:	GStreamer
Classification:	Platform
Component:	gst-plugins-bad
Version:	git master
Hardware:	Other Linux

Importance:	Normal normal
Target Milestone:	0.10.9
Assigned To:	GStreamer Maintainers
QA Contact:	GStreamer Maintainers

URL:
Whiteboard:

Depends on:
Blocks:

Reported:	2008-09-25 09:53 UTC by Sebastian Dröge (slomo)
Modified:	2008-10-08 10:21 UTC

See Also:
GNOME target:	---
GNOME version:	---

Description Sebastian Dröge (slomo) 2008-09-25 09:53:41 UTC

Hi,
when playing tv2-1_25.mpg with mpegpsdemux one gets a FP exception. This might be caused by the stream starting at a timestamp > 0. Old mpegdemux works without problems...

Program received signal SIGFPE, Arithmetic exception.

+ Trace 207304

Thread 3067325328 (LWP 5870)

#0 __udivdi3
from /home/slomo/projects/gstreamer/head/gst-plugins-bad/gst/mpegdemux/.libs/libgstmpegdemux.so
#1 gst_flups_demux_chain
at gstmpegdemux.c line 1140
#2 gst_pad_chain_unchecked
at gstpad.c line 3877
#3 gst_pad_push
at gstpad.c line 4045
#4 gst_base_src_loop
at gstbasesrc.c line 2187
#5 gst_task_func
at gsttask.c line 192
#6 g_thread_pool_thread_proxy
at /tmp/buildd/glib2.0-2.18.1/glib/gthreadpool.c line 265
#7 g_thread_create_proxy
at /tmp/buildd/glib2.0-2.18.1/glib/gthread.c line 635
#8 start_thread
from /lib/i686/cmov/libpthread.so.0
#9 clone
from /lib/i686/cmov/libc.so.6



http://samples.mplayerhq.hu/MPEG-VOB/interlaced/tv2-1_25.mpg

Comment 1 Sebastian Dröge (slomo) 2008-09-25 09:54:23 UTC

Code in question is:

adjust = (bss * CLOCK_FREQ) / old_mux_rate;

So most probably a division by zero ;)

Comment 2 Jan Schmidt 2008-09-25 11:12:35 UTC

How old is "old mpegdemux"? afair there used to be a sanity check that the mux_rate was != 0 before doing the division

Comment 3 Sebastian Dröge (slomo) 2008-09-25 14:18:11 UTC

(In reply to comment #2)
> How old is "old mpegdemux"? afair there used to be a sanity check that the
> mux_rate was != 0 before doing the division

With "old mpegdemux" I meant the one from -ugly. There was a bug with this file too but it was fixed before last release.

Comment 4 Sebastian Dröge (slomo) 2008-10-08 10:21:07 UTC

2008-10-08  Sebastian Dröge  <sebastian.droege@collabora.co.uk>

	* gst/mpegdemux/gstmpegdemux.c: (gst_flups_demux_send_data),
	(gst_flups_demux_parse_pack_start):
	Prevent a division by zero if last mux rate was zero.

	If we're going to send a NEWSEGMENT event but the segment start
	and the current buffer timestamp differ by more than a second we
	will start the NEWSEGMENT at the buffer timestamp.

	This fixes playback of the tv2-1_25.mpg file, which has 0 as first SCR
	but the first PTS are around 1 hour and 40 minutes.

	Fixes bug #553755.