Components

ZoneMinder is not a single monolithic application but is formed from several
components. These components primarily include executable compiled binaries
which do the main video processing work, perl scripts which usually perform
helper and/or external interface tasks and php web scripts which are used
for the web interface.
System Overview

Depicted below is a high level diagram of the ZoneMinder system with key
components
    

A brief description of each of the principle components follows.
Binaries

zmc
    This is the ZoneMinder Capture daemon. This binary’s job is to sit on
a video device and suck frames off it as fast as possible, this should run
at more or less constant speed.
zma
    This is the ZoneMinder Analysis daemon. This is the component that goes
through the captured frames and checks them for motion which might generate
an alarm or event. It generally keeps up with the Capture daemon but if very
busy may skip some frames to prevent it falling behind.
zms
    This is the ZoneMinder Streaming server. The web interface connects with
this to get real-time or historical streamed images. It runs only when a
live monitor stream or event stream is actually being viewed and dies when
the event finishes or the associate web page is closed. If you find you have
several zms processes running when nothing is being viewed then it is likely
you need a patch for apache (see the Troubleshooting section). A non-parsed
header version of zms, called nph-zms, is also installed and may be used
instead depending on your web server configuration.
zmu
    This is the ZoneMinder Utility. It’s basically a handy command line
interface to several useful functions. It’s not really meant to be used by
anyone except the web page (there’s only limited ‘help’ in it so far)
but can be if necessary, especially for debugging video problems.

PHP

As well as this there are the web PHP files in the web directory. Currently
these consist of a single skin with Classic and Flat styles.

Classic
    Original ZoneMinder skin
Flat
    An updated version of Classic skin, retaining the same layout with a
more modern style. Originally a skin this is now just a CSS style.

Perl

Finally some perl scripts in the scripts directory. These scripts all have
some configuration at the top of the files which should be viewed and
amended if necessary and are as follows.

zmpkg.pl
    This is the ZoneMinder Package Control script. This is used by the web
interface and service scripts to control the execution of the system as a
whole.
zmdc.pl
    This is the ZoneMinder Daemon Control script. This is used by the web
interface and the zmpkg.pl script to control and maintain the execution of
the capture and analysis daemons, amongst others. You should not need to run
this script yourself, although you can use it to start/top individual ZM
processes.
zmfilter.pl
    This script controls the execution of saved filters and will be started
and stopped by the web interface based on whether there are filters that
have been defined to be autonomous(background). This script is also
responsible for the automatic uploading of events to a 3rd party server.
Prior to 1.32 there was one zmfilter.pl process. In 1.32 onwards we start a
zmfilter.pl process for each background filter so that the processing time
of one filter doesn’t delay the processing of another filter.
zmaudit.pl
    This script is used to check the consistency of the event file system
and database. It can delete orphaned events, i.e. ones that appear in one
location and not the other as well as checking that all the various event
related tables are in line. It can be run interactively or in batch mode
either from the command line or a cron job or similar. In the zmconfig.pl
there is an option to specify fast event deletes where the web interface
only deletes the event entry from the database itself. If this is set then
it is this script that tidies up the rest. We do not recommend fast event
deletion and we do not recommend having zmaudit.pl run in the background. It
is a very ram cpu and disk io intensive program, constantly scanning every
event. Please run it manually or from a cron job on weekends or something.
zmwatch.pl
    This is a simple script purely designed to keep an eye on the capture
daemons and restart them if they lockup. It has been known for sync problems
in the video drivers to cause this so this script makes sure that nothing
important gets missed.
zmupdate.pl
    Currently this script is responsible for checking whether a new version
of ZoneMinder is available and other miscellaneous actions related to
upgrades and migrations. It is also intended to be a ‘one stop shop’ for
any upgrades and will execute everything necessary to update your
installation to a new version.
zmvideo.pl
    This script is used from the web interface to generate video files in
various formats in a common way. You can also use it from the command line
in certain circumstances but this is not usually necessary.
zmx10.pl
    This is an optional script that can be used to initiate and monitor X10
Home Automation style events and interface with an alarm system either by
the generation of X10 signals on ZoneMinder events or by initiating
ZoneMinder monitoring and capture on receipt of X10 signals from elsewhere,
for instance the triggering of an X10 PIR. For example I have several
cameras that don’t do motion detection until I arm my alarm system
whereupon they switch to active mode when an X10 signal is generated by the
alarm system and received by ZoneMinder.
zmtrigger.pl

    This is an optional script that is a more generic solution to external
triggering of alarms. It can handle external connections via either internet
socket, unix socket or file/device interfaces. You can either use it ‘as
is’ if you can interface with the existing format, or override connections
and channels to customise it to your needs. The format of triggers used by
zmtrigger.pl is as follows “|||||” where

        ‘id’ is the id number or name of the ZM monitor.
        ‘action’ is ‘on’, ‘off’, ‘cancel’ or ‘show’
where ‘on’ forces an alarm condition on, ‘off’ forces an alarm
condition off and ‘cancel’ negates the previous ‘on’ or ‘off’.
The ‘show’ action merely updates some auxiliary text which can
optionally be displayed in the images captured by the monitor. Ordinarily
you would use ‘on’ and ‘cancel’, ‘off’ would tend to be used to
suppress motion based events. Additionally ‘on’ and ‘off’ can take
an additional time offset, e.g. on+20 which automatically ‘cancel’s the
previous action after that number of seconds.
        ‘score’ is the score given to the alarm, usually to indicate
it’s importance. For ‘on’ triggers it should be non-zero, otherwise it
should be zero.
        ‘cause’ is a 32 char max string indicating the reason for, or
source of the alarm e.g. ‘Relay 1 open’. This is saved in the
‘Cause’ field of the event. Ignored for ‘off’ or ‘cancel’
messages.
        ‘text’ is a 256 char max additional info field, which is saved
in the ‘Description’ field of an event. Ignored for ‘off’ or
‘cancel’ messages.
        ‘showtext’ is up to 32 characters of text that can be displayed
in the timestamp that is added to images. The ‘show’ action is designed
to update this text without affecting alarms but the text is updated, if
present, for any of the actions. This is designed to allow external input to
appear on the images captured, for instance temperature or personnel
identity etc.

    Note that multiple messages can be sent at once and should be LF or CRLF
delimited. This script is not necessarily intended to be a solution in
itself, but is intended to be used as ‘glue’ to help ZoneMinder
interface with other systems. It will almost certainly require some
customisation before you can make any use of it. If all you want to do is
generate alarms from external sources then using the ZoneMinder::SharedMem
perl module is likely to be easier.
zmcamtool.pl
    This optional script is new for the upcoming 1.27 release of ZoneMinder.
It is intended to make it easy to do the following: bring in new ptz
controls and camera presets, convert existing monitors into presets, and
export custom ptz controls and presets. For the initial release, this script
is not integrated into the UI and must be called from the command line. Type
‘’zmcamtool.pl –help’’ from the command line to get an explanation
of the different arguments one can pass to the script.
zmcontrol-*.pl
    These are a set of example scripts which can be used to control
Pan/Tilt/Zoom class cameras. Each script converts a set of standard
parameters used for camera control into the actual protocol commands sent to
the camera. If you are using a camera control protocol that is not in the
shipped list then you will have to create a similar script though it can be
created entirely separately from ZoneMinder and does not need to named as
these scripts are. Although the scripts are used to action commands
originated from the web interface they can also be used directly or from
other programs or scripts, for instance to implement periodic scanning to
different presets.
zmtrack.pl
    This script is used to manage the experimental motion tracking feature.
It is responsible for detecting that an alarm is taking place and moving the
camera to point to the alarmed location, and then subsequently returning it
to a defined standby location. As well as moving the camera it also controls
when motion detection is suspended and restored so that the action of the
camera tracking does not trigger endless further alarms which are not
justified.
zm
    This is the (optional) ZoneMinder init script, see below for details.
zmeventnotification.pl
    This is an optional 3rd party real time event notification server that
also provides push notifications for zmNinja as well as machine learning
powered object/face-detection. Please see Event Notification Server
Documentation for more details (Note that the machine learning components
are optional, and are developed in Python3)

Finally, there are also a number of ZoneMinder perl modules included. These
are used by the scripts above, but can also be used by your own or 3rd party
scripts. Full documentation for most modules is available in ‘pod’ form
via ‘perldoc’ but the general purpose of each module is as follows.

ZoneMinder.pm
    This is a general ZoneMinder container module. It includes the Base.pm,
Config.pm Debug.pm, Database.pm, and SharedMem.pm modules described below.
It also exports all of their symbols by default. If you use the other
modules directly you have request which symbol tags to import.
ZoneMinder/Base.pm
    This is the base ZoneMinder perl module. It contains only simple data
such as version information. It is included by all other ZoneMinder perl
modules
ZoneMinder/Config.pm
    This module imports the ZoneMinder configuration from the database.
ZoneMinder/Debug.pm
    This module contains the defined Debug and Error functions etc, that are
used by scripts to produce diagnostic information in a standard format.
ZoneMinder/Database.pm
    This module contains database access definitions and functions.
Currently not a lot is in this module but it is included as a placeholder
for future development.
ZoneMinder/Event.pm
    This module contains functions to load, manipulate, delete, copy, move
events.
ZoneMinder/Filter.pm
    This module contains functions to load, execute etc filters.
ZoneMinder/SharedMem.pm
    This module contains standard shared memory access functions. These can
be used to access the current state of monitors etc as well as issuing
commands to the monitors to switch things on and off. This module
effectively provides a ZoneMinder API.
ZoneMinder/ConfigAdmin.pm
    This module is a specialised module that contains the definition, and
other information, about the various configuration options. It is not
intended for use by 3rd parties.
ZoneMinder/Control/*.pm
    These modules contain implementations of the various PTZ protocols.
ZoneMinder/Trigger/*.pm
    These modules contain definitions of trigger channels and connections
used by the zmtrigger.pl script. Although they can be used ‘as is’, they
are really intended as examples that can be customised or specialised for
different interfaces. Contributed modules for new channels or connections
will be welcomed and included in future versions of ZoneMinder.