Opened 12 years ago

Closed 11 years ago

#4951 closed defect (invalid)

Mythtv 0.21-fixes segfaults when playing a DVD

Reported by: Tyson Harding <tharding@…> Owned by: Isaac Richards
Priority: minor Milestone: unknown
Component: mythtv Version: 0.21-fixes
Severity: medium Keywords:
Cc: Ticket locked: no

Description

Anytime I try to play a DVD mythtv segfaults. It isn't always at the same point in the DVD, even for the same DVD, but it does always happen when starting a new track, whether it is the initial track when the DVD is just started, or when switching to the next movie preview at the beginning of the DVD, or once the movie is selected from the main menu.

Attached is the gdb backtrace from 0.21-fixes

Attachments (2)

gdb.txt (23.1 KB) - added by Tyson Harding <tharding@…> 12 years ago.
myth.log (24.4 KB) - added by Tyson Harding <tharding@…> 12 years ago.

Download all attachments as: .zip

Change History (7)

Changed 12 years ago by Tyson Harding <tharding@…>

Attachment: gdb.txt added

comment:1 Changed 12 years ago by skamithi

looks like you are using opengl video renderer which is still experimental. Use the xv-blit renderer instead.

if you want to help the test opengl video renderer run the mythtv-vid branch and test again. see if it crashes using opengl video renderer there.

comment:2 in reply to:  1 ; Changed 12 years ago by Tyson Harding <tharding@…>

Replying to skamithi:

looks like you are using opengl video renderer which is still experimental. Use the xv-blit renderer instead.

My system seems to be "falling back" to the opengl renderer. I'm using XvMC on nVidia hardware, and in my playback profile I have xvmc-blit, but in the output logs mythtv will show that is falls back to opengl. What do I need to do to prevent that? None of my playback profiles have the opengl video renderer selected. I am attaching the myth.log from this run.

if you want to help the test opengl video renderer run the mythtv-vid branch and test again. see if it crashes using opengl video renderer there.

I would love to do this, but I am starting to get swamped with other stuff and am switching to the released version until I have more time to play, and provide useful feedback. If I can perform a quick test without upgrading my backend from the 0.21-fixes branch I am happy to give it a try.

Changed 12 years ago by Tyson Harding <tharding@…>

Attachment: myth.log added

comment:3 in reply to:  2 Changed 12 years ago by Tyson Harding <tharding@…>

Replying to Tyson Harding <tharding@cs.utah.edu>:

Replying to skamithi:

looks like you are using opengl video renderer which is still experimental. Use the xv-blit renderer instead.

My system seems to be "falling back" to the opengl renderer. I'm using XvMC on nVidia hardware, and in my playback profile I have xvmc-blit, but in the output logs mythtv will show that is falls back to opengl. What do I need to do to prevent that? None of my playback profiles have the opengl video renderer selected. I am attaching the myth.log from this run.

I figure out why it was falling back to the opengl renderer. My machine is one that can just barely play HD content, and only if I use XvMC. What I had found was that with all of the changes that had been made to the playback profiles, and using XvMC libraries, that if I used the --xvmc-lib=XvMCNVIDIA --enable-opengl-video --enable-xvmc-opengl option I could get my machine to play HD. If I only include the --xvmc-lib=XvMCNVIDIA option then it correctly uses the xvmc-blit renderer and I don't get this segfault, and I can play HD.

So this segfault does exist, but may be fixed in the -vid branch, it is up to you if you want to leave it open and try and fix it in the 0.21-fixes branch, or close it with a note that this is a discouraged, or untested configuration.

comment:4 Changed 12 years ago by laga@…

I've created a small workaround which will fall back to 'xv-blit' instead. Basically, it's reordering the list of video renderers when the selected one fails.

Index: libs/libmythtv/videoout_xv.cpp
===================================================================
--- libs/libmythtv/videoout_xv.cpp      (revision 16772)
+++ libs/libmythtv/videoout_xv.cpp      (working copy)
@@ -4313,12 +4313,12 @@
     QStringList list;
     if (myth_codec_id < kCodec_NORMAL_END)
     {
-        if (opengl)
-            list += "opengl";
         if (xv)
             list += "xv-blit";
         if (shm)
             list += "xshm";
+        if (opengl)
+            list += "opengl";
         list += "xlib";
     }
     else

The patch in ticket #4792 also looks promising...

comment:5 Changed 11 years ago by danielk

Resolution: invalid
Status: newclosed

Looks like this was an audio issue, but we've fixed a number of audio bugs in trunk since this was opened. But it looks like the ticket submitter was also running some experimental code, so I'm closing this as invalid since we really need a clean backtrace without experimental code and at this point we need that backtrace with trunk since this has probably been fixed already.

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