Video and audio delay application examples.
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DelayLine Applications


Action Replay

DelayLine video delay system temporarily stores up to 1 minute of video. It is therefore possible to use the system to replay an event of interest without the need to stop and rewind a video recorder. For example, a CCTV operator can double-check if an offence has taken place by switching to the delayed video, which will replay the event a few seconds later.

Installation is very straightforward. Simply take the video out from the viewing monitor and feed it into the DelayLine unit. The output of the DelayLine video delay unit can then be viewed on a second monitor or by connecting to the monitor’s “B” input, if available.

Event Capture / Repeating Action Replay




With an external video switch and monitor, DelayLine can be used to capture an event and constantly repeat it. With the switch in the normal “view” position the operator sees the live video. If an event of interest occurs, the operator may switch over to the delayed version, which will replay the event (of say 10 seconds duration) and then constantly repeat the event as it is fed back into the DelayLine.

(NB: the same video is being fed into the DelayLine each time, and therefore degradation occurs over a period of time. However, the system is capable of at least 10 to 20 repeats of good quality video.)


CCTV Spot Monitor Event Recorders


Within CCTV systems, VCRs are often connected to the operator’s spot monitors to record events of interest in real-time. The problem is that often by the time the operator has pressed the record button and the VCR is up and running, the event has past. By introducing DelayLine between the spot viewing monitor and the operator’s VCR, it is possible to ensure the complete event is captured. This is because the video to the VCR is delayed, so when the operator presses the record button, the VCR has 15 (or more) seconds to start recording before the event is output by DelayLine.



Time-Lapse VCR Pre-Event Recording




DelayLine can be used to upgrade a standard time-lapse VCR to pre-event recording. This is an advanced feature, which is normally associated with digital hard-disk recorders rather than traditional VCRs.

A time-lapse VCR can normally be set to record in real-time form either time-lapse or standby under the control of an external alarm input. The major problem with this approach is that it takes time for the VCR to change mode, which can result in a vital loss of footage. By introducing a delay in the video feed (and not the alarm input) of the VCR, the change of mode takes place before the event, resulting in pre-alarm recording.


Dial-up video Surveillance




Alarm triggered, dial-up video surveillance often has the problem of missing important events because of the time taken to establish the network connection. DelayLine may be used to temporarily store the event in its memory, allowing the overall system time to dial-up and start transmitting video.



Sports Coaching


Video recorders are often used in sports coaching. However, whilst VCR recordings are useful in analysing performance after a match, they are not suitable for repetitive record / replay of short duration events. For example when practising golf, DelayLine can be used to replay each swing of the club 20 seconds later. This allows the player to take a shot, see how effective it was and then view a replay of the swing on a video monitor. The player is therefore instantly able to gauge the characteristics of a good or bad shot. In this type of application DelayLine has the major advantage as it does not require constant user intervention, unlike a tape-based system.


Synchronising Video & Audio Feeds



Digital video and audio compression and transmission systems can introduce differing amounts of delay to video and audio signals. “Lip-Sync” requires video and audio synchronisation with 50mS otherwise the viewer becomes distracted by the lack of coordination between the subject’s lips and voice. If the audio is delayed more than the video, DelayLine can be used to synchronise the two feeds with 50mS to regain “Lip-Sync”.

Due to continual product development Ovation Systems reserve the right to change specifications without notice. E&OE.