[8.10] mythzmserver will not display live feed

[noisymime]

Binary package hint: mythplugins

System: Ubuntu 8.10 Alpha 6
zoneminder: 1.23.3-3
mythzoneminder: 0.21.0+fixes18379-0ubuntu1

Installed package mythzoneminder which loads fine in mythfrontend however will not display any live video feeds. When opening the live stream window only a black box is shown. This occurs for GL, XV and RGB display options.

mythzmserver output:
: sudo mythzmserver -c /etc/zm/zm.conf
loading zm config from /etc/zm/zm.conf
ZM is version '1.23.3'
Listening on port: 6548
Failed to shmget for monitor: 1
ENOENT - no segment exists for the given key
Failed to shmget for monitor: 3
ENOENT - no segment exists for the given key

mythfrontend (-v most) output:
2008-10-02 09:44:03.099 MythZoneMinder: Using Xv for display
2008-10-02 09:44:03.111 Found 0 Xv adaptors
2008-10-02 09:44:03.111 WARNING: Couldn't find free Xv adaptor with RGB XvImage support
2008-10-02 09:44:03.111 Falling back to XImage - slow and ugly rescaling
2008-10-02 09:44:03.111 write -> 26 20 GET_LIVE_FRAME[]:[]1
2008-10-02 09:44:03.111 read <- 26 46 ERROR - Cannot get shared memory pointers[]:[]
2008-10-02 09:44:03.111 The server failed to process the command. The error was:-
                        ERROR - Cannot get shared memory pointers
2008-10-02 09:44:03.214 write -> 26 20 GET_LIVE_FRAME[]:[]1
2008-10-02 09:44:03.214 read <- 26 46 ERROR - Cannot get shared memory pointers[]:[]
2008-10-02 09:44:03.214 The server failed to process the command. The error was:-
                        ERROR - Cannot get shared memory pointers
2008-10-02 09:44:03.315 write -> 26 20 GET_LIVE_FRAME[]:[]1
2008-10-02 09:44:03.315 read <- 26 46 ERROR - Cannot get shared memory pointers[]:[]
2008-10-02 09:44:03.315 The server failed to process the command. The error was:-
                        ERROR - Cannot get shared memory pointers

Error message repeats for as long as live stream screen is open.
(Whilst there is an error above saying that Xv could not be loaded, this is unrelated as the same problem is experienced on another system where Xv works normally)

Zoneminder is setup correctly and video can be displayed via web interface so the problem is with myth zoneminder. Same setup worked with mythzoneminder under 8.04.

Suggested cause:
This is possibly due to a limitation of mythzoneminder:
http://www.mythtv.org/wiki/index.php/MythZoneMinder#Dependencies
Above site states that mythzoneminder only works with zoneminder versions 1.22.2 and 1.22.3 whereas Intrepid has upgraded to zoneminder 1.23.3. Not 100% sure this is the cause of the problem, but it is a possibility.

If the versioning issue above is the issue, it will obviously need to wait until the problem is fixed upstream, but in the mean time it should be documented somewhere that package mythzoneminder will not work on Intrepid.

[noisymime (josh-noisymime)]

Problem is due to ZoneMinder 1.23.3 using a different value for its shared memory key. Patch has been submitted upstream but it makes some changes to mythzmserver that may not be accepted.

Temporary workaround for anyone experiencing this issue is the following:
In zoneminder mysql database, in table 'config', change the 'Value' field of setting 'ZM_SHM_KEY' to be the same as the 'DefaultValue' field. Restart mythzmserver.

[noisymime (josh-noisymime)]

mythzoneminder creator states that this problem is due to a corrupt shared memory key and hence no need for a patch.

As I tested this on a fresh mythbuntu install, I am concerned that this problem is not just a once off and that it may occur all mythbuntu 8.10 installs.

Is anyone else able to test this?

[Wolf Geldmacher (wolf-womaro)]

Verified on 8.10 after an upgrade from 8.04 and on a fresh 8.10 install.

Workaround works as advertised.

[Kyle Gordon (kylegordon)]

I can also confirm that this is a fault in Intrepid.

I have tried the workaround as described by noisemime, but the Value field is already the same as DefaultValue field anyway. I have been unable to find an earlier version of mythzoneminder to download (other than compiling it myself).

Regards

Kyle

[noisymime (josh-noisymime)]

@Kyle Gordon

What is the value of the 2 fields? If it ends in anything other than 4 0's then I believe it will cause a problem (Mine was originally 0x7a6d2000 for example)

If you change both fields to end in 4 0's (in my case changing to 0x7a6d0000), restart mythzmserver and you should be OK.

[MarcRandolph (mrand)]

Closing. Solution is outlined in Comment #5, which summarizes what upstream said regarding the last four digits.