Ring Buffer

Click on the entry Ring buffers to open the setting dialog of the global FLTM settings.

Read more about FLTM here, if you are not familiar with this function.

Select the option field Suppress FLTM during review and the corresponding times if you do not wish FLTM actions to be performed during these times.

Under Advanced settings you can set the suppression more precisely.

When you have made your settings, click on the cross before the entry Ring buffer to make the settings for the ring buffer. Click on the ring that you wish to configure and open the newly appeared tab Ring buffer.

You can give the ring buffer a name and must decide whether you would like to set the ring buffers to Classic mode or Fading Long Term Memory (FLTM) mode.

Classic Mode

The eight recording rings will appear to the left of the settings dialog, while the setting for the ring buffer depth is shown on the right.

To set the recording depth, click on the ring whose settings you wish to change. The settings dialog is displayed.

The depth of the ring buffer is given in days, hours and minutes, each of which is divided into 5 archive levels; the first level represents permanent recording.

Moreover, there are two selection fields:

Field	Description
Priority	Mark this selection field if the pictures at this archive level should remain kept for a very long period. Dependent on the database space requirements, the retention period is extended to several hundred days. However, the pictures are overwritten at some stage. This setting is roughly equivalent to the "blocked event" setting in MSCIII.
Auto hide (if depth exceed)	If you mark this selection field, the images of this archive level will be hidden for the operator after the set time has expired.

What Does Ring Buffer Depth Mean?

To imagine that your database is simply divided by 8, and that each eighth part corresponds to one ring, is close but, unfortunately, wrong. On the one hand, space would be wasted if rings were not adequately supplied with images, and on the other hand rings could quickly overflow and image material be prematurely released for overwriting.

Rings involve dynamic management of the database space. In other words, if, due to the quantity and/or size of the images, a ring "overflows" the space that has been reserved, the system checks the location of the images that are furthest from the set ring buffer depth. These images are then released for overwriting. This makes optimum use of the available database space, and ensures that the configured ring buffer depth is maintained.

What Does Archive Level Mean?

The archive level permits the memory size for each event to be adjusted in accordance with the available hard disk space and with the desired archiving time. You make use of these levels, specified in days, hours and minutes, when, for instance, configuring events, in order to control the way in which recorded events are overwritten.

The eight rings, each with its five archive levels, can be thought of as one G-Core with 40 rings. These archive levels are not a substitute for recording in the rings, as it is only in the eight rings that it is possible to record simultaneously with any desired archive level. The first archive level contains the setting for permanent recording.

It is not necessary to calculate the capacity. It is simply a matter of setting the required recording times for permanent recordings and, if relevant, events that are to be stored for a longer period. The system automatically ensures that the total available database capacity is optimally distributed over all the configured recording processes.

See also the chapter Considerations Governing Database Management.

FLTM Mode

General

The FLTM feature is an extension of the functionality of the database. The core target is to increase the database recording depth by automatically reducing the picture rates for older recordings. This originates from the thoughts that older pictures, dependent on the application, are less significant than newer pictures. At the same time, the FLTM feature at least secures the availability of a reduced stock of picture information with older recordings.

The FLTM feature can be optionally activated. So far the standard has been the previous deletion of the respective oldest images in an archive level, if memory is required for recording.

The following approach is followed for technical realization:

If the DBE requires recording capacity in a source archive level recording capacity, not only simple memory blocks are overwritten if FLTM is active, but several source archive level memory blocks are merged in accordance with the FLTM pack parameters.
The blocks merged by FLTM are then available for recording in the source archive level.
The block created by FLTM is recorded in a special target archive level especially for this purpose. This target archive level is set at a higher time depth than the source archive level in order to ensure a higher retention period of the packed picture data in the database than in the source archive level.
This procedure ensures that beyond the achieved source level time depth only picture data with a reduced picture rate in accordance with the FLTM settings is available.

FLTM is hence equivalent to a database-internal packing / copying process from an archive level with a low recording depth (but a high picture rate) to a different archive level with a considerable recording depth (but a low picture rate).

FLTM works independent of the time depth of the source archive level set in setup if capacity has to be created in the source archive level due to recording requirements.

If the total capacity of the database is not sufficient to achieve the time depth set in the archive levels, this also leads to the packing process already being started before the archive depth set is reached. If, on the other hand, database capacity is higher than required, FLTM also starts later. Inevitably, the approach means that it is not exactly possible to forecast the time recording depth at which the packing (and with it the "fading") of the picture data starts.

The definition of the FLTM function at archive level can also cause different behavior, depending on the meaning of the recordings. Thus, for example, packing older event recordings can run differently to packing less important permanent recordings.

The packing process maintains the event data available belonging to the pictures after packing.

The procedures described affect the disc performance as a result of simultaneous read and write procedures. This is normal and cannot be avoided when, in addition to saving new pictures, old pictures are retrieved from the database, processed in memory and then (having been reduced) written back. FLTM A alone thus requires in general roughly 60% of the disc drive performance for execution. For this reason (and to avoid shaky pictures during this time when viewing database recordings), there are two settings on the Ring buffer tab that counteract this problem.

When you activate the field "Suppress FLTM during review", the FLTM function is then suppressed. Viewing pictures and picture sequences from the database thus is given priority. The type of the suppression is set under "Advanced settings" under "Review suppression factor". An entry of 50% (corresponds to spread of the FLTM activity to one and a half days) has proved to be a reliable setting in real-world applications.

Another possibility for suppressing the FLTM activity, instead of using the "Suppress FLTM during review" field, is to select a defined time period in which the FLTM activity is to be suppressed. Some examples: Let us assume that the time range Week 001 applies to daytime and Week 002 applies to the night. In such a case it is possible to enable activity during the night (Week 02) and suppress it during the daytime (Week 001). If we have a relationship of 16 hours of daytime and 8 hours of night, then it is possible, however, that FLTM cannot finish its work in this time. This would make FLTM pointless. The first option for setting the suppression may thus be preferable.

For H.264 in conjunction with FLTM, you should know that I-frame based pictures (entire GOPs) will be lost!

Click here to jump to the start of the chapter Ring buffer. Otherwise, continue reading.

Settings

If you select the FLTM mode, you extend the setting options for the ring selected. In addition to the settings for the permanent recording archive level (Archive level 1), you have two configurations for deleting the pictures: FLTM A and FLTM B. As a standard, only FLTM A is active.

FLTM A

In the FLTM mode, the first FLTM setting (FLTM A) is automatically activated.

Set the time (as a "Desired value") according to which the database should be thinned out.

As in the classical mode, the database is already thinned-out earlier if disk space is needed. However, if sufficient disk space is available, the process can also take effect later then specified.

Moreover, the selection fields Priorityand Auto hide (if depth exceed)are also available and have the same meaning as in classical mode. The selection field Keep audiois new: Mark this selection field if you wish to retain existing audio data during the packaging process.

Shrink Mode

Shrink mode has three different settings:

Settings	Description
Keep just event pictures	Only event pictures are kept, all other pictures are deleted.
Keep every n'th picture	The default setting is 50. In this case, every 50th picture is kept.
Interval	Set the interval here at which pictures should be deleted. The default setting is one picture every 2 seconds.

FLTM B

Also activate the FLTM B function. Then, after the set period (also only a "Desired value") the part already thinned-out by FLTM A is thinned-out further in accordance with your settings.

Otherwise, the settings match the FLTM A settings.

Global Database Settings

In the Global database settings area, you can centrally limit the storage depth for all ring buffers. Depending on the settings and storage depth, all video and event data is hidden or deleted after the specified time in the system. These settings support you in the data protection-compliant setup of your G-Core system.

The following global database settings are available:

Settings	Description
Default (Ringbuffer specific settings)	The settings of the individual ring buffers apply.
Automatically hide in all Ringbuffers	The video and event data are no longer visible to the operator after the specified time.
Automatically erase in all Ringbuffers	The video and event data are deleted from the database after the specified time and cannot be recovered. The automatic deletion can take some time with an existing database until the storage depth is limited and the video data has been deleted. The automatic deletion can only be set in the global database settings for all ring buffers. The automatic deletion can be set individually per ring buffer or globally.
Global storage depth override	Here you can specify a central storage depth for all ring buffers. Note that this will overwrite individual specifications in the ring buffers.