Using a microphone with CCTV and setting up

[Numb-nuts 1]

When I first became interested in CCTV it was as a result of chatting with the guy

from our local council's Anti-social behaviour team, who installs CCTV in victims

homes for evidential purpose. We have had many chats since then and I've even

loaned him some equipment which fitted with particular situations.

 

He contacted me this week saying he was setting up a surveillance for a family that are

subject of "racist hate crime" and verbal taunts are a big part of the harrasment they are

experiencing. I have a microphone to loan him, however I understand that there are some

issues with sound synchronization with the picture frame rates etc.

 

Firstly how is the connection done?

Second what recording parameters are required to sync the sound and picture?

 

Remember, the captured sound and video must be evidential quality. ANY ADVICE

 

OOH Just found this.

[rory 0]

local council's Anti-social behaviour team.

What on earth is that? Why would anyone care if someone wants to be social or not?

[Soundy 1]

Before you proceed, you might want to look into the legality of audio surveillance in your region... some areas allow you to listen but not record, some allow you to record, some require you post signage to the effect that audio is being used, and in many states, audio surveillance is illegal altogether. Here in BC, audio recording is legal, but is inadmissible for evidence unless you post signs informing people they're being recorded.

[Numb-nuts 1]

Before you proceed, you might want to look into the legality of audio surveillance in your region... some areas allow you to listen but not record, some allow you to record, some require you post signage to the effect that audio is being used, and in many states, audio surveillance is illegal altogether. Here in BC, audio recording is legal, but is inadmissible for evidence unless you post signs informing people they're being recorded.

A good point, but not what I asked.

For one thing, I think that adding signage might be a good thing, it will either encourage offenders to escalate their behaviour in which case evidence can be obtained, or warn offenders off altogether. Police and councils take this sort of harassment very seriously due to specific high profile tragedies such as the Fiona Pilkington case.

 

I am merely attempting to assist by loaning a microphone for free and assuring it can be used effectively.

 

Staying on thread, does anyone have any technical advice for ensuring recordings are in sync with the sound?

[ak357 0]

Staying on thread, does anyone have any technical advice for ensuring recordings are in sync with the sound?

 

What are u going to use for video recording ?

as long as u use Real time for video u should not have problem with audio

[Numb-nuts 1]

Thats interesting, what do you consider to be real time?

Personally I record at between 6 to 12 fps which is ideal for evidential purposes and is not so poor that fluid motion is lost.

I hear talk of computer video editing and often hear that 25 - 100 fps is desirable. Most DVRs that I have seen record at a Maximum of 25 fps so is that what you mean as real time?

 

The DVR the council uses records at around 6 - 12 fps and is accessed via the 3g network so file size is an issue, however if it is just a matter of the frame speed keeping up with sound files, I can always loan them another DVR as well as a microphone that they will have to attend to download evidence.

 

I think I'll do a little trial run to see if that is all that is needed to achieve synchronization of sound and video. If I do some testing at differing speeds until I find the one that is the optimum.

 

PS AK, your little crawling ant drive me crazy

[Soundy 1]

The only DVRs I've actually used the audio features on have been Vigils, and the audio syncs just fine with the video regardless of framerate, no extra tinkering required. I've seen it used on a couple old MUX/VCR installations and there was nothing special done to sync that, either. With lower framerates, the picture may "skip" along, but the sound shouldn't, and it shouldn't go "out of sync" with the picture... or if it does, it should be only offset by a fixed amount (it would take upward of 100ms to really be noticeable) that can be easily compensated for on playback.

 

Have you tested this yet with the setup in question, or are you just assuming there will be issues because someone told you there would be? Unless it's a really low-quality DVR, I don't think you'll see any issues - again, if anything, I would expect the sync to be off by a fixed amount, probably no more than a few hundred milliseconds, through the length of the recording, so it should still be easy enough to tell that the audio "matches" the video. I can't think of any reason the offset would "wander" through the timeline.

 

As for checking on the legality, the point is that you could save yourself some time and trouble worrying about the sync issue if you find out that it IS illegal. Plus, if it's illegal, and you just supply your client with the microphone to do it, you could be opening yourself up to a lawsuit, if he were to be caught and charged and then claim that you, as the "CCTV professional", "should have known and warned him of the potential liability."

[tomcctv 190]

I am merely attempting to assist by loaning a microphone for free and assuring it can be used effectively.

 

Staying on thread, does anyone have any technical advice for ensuring recordings are in sync with the sound?

 

 

from your link posted you are in the uk. like soundy said it is illegal to record sound in the uk if you are not licenced to do so. and you also need a licence to hide covert in a public space area. and with you asking on how to wire up a microphone and your friend also not knowing how tends to surgest that you have not done this before and so not licenced. your not doing it for money your lending your mic. you have lost nothing from the job so just walk away.

 

 

and about signage. you say it might warn the offenders off. is that not what you want as an end result

[Numb-nuts 1]

you have lost nothing from the job so just walk away.

 

 

and about signage. you say it might warn the offenders off. is that not what you want as an end result

 

I want to talk about the technical concern of syncing sound and video thats all.

Edited February 16, 2011 by Guest

[Numb-nuts 1]

[Soundy 1]

I want to talk about the technical concern of syncing sound and video thats all.

Like I already said, there is none.

[Dirk_D 0]

I'd think a wearable mic would be the only way to get quality audio.

 

Something like this: http://www.amazon.com/Olympus-WS-400-Digital-Recorder-White/dp/B00264TQQM/ref=dp_ob_title_ce?tag=gpse-20

 

This one in a shirt pocket would work, but simulate the situation - clothes rustling, wind blowing, etc. Prolly do better with an external mic.

[Soundy 1]

I'd think a wearable mic would be the only way to get quality audio.

 

Something like this: http://www.amazon.com/Olympus-WS-400-Digital-Recorder-White/dp/B00264TQQM/ref=dp_ob_title_ce?tag=gpse-20

 

This one in a shirt pocket would work, but simulate the situation - clothes rustling, wind blowing, etc. Prolly do better with an external mic.

Yeah, pickup pattern/area/distance is a FAR bigger concern than audio/video sync. It's not like a camera, where you can focus on one particular area - a mic will pick up EVERYTHING in the room (or within its pickup pattern, but most mics used for this kind of thing are either omnidirectional, or a very broad cardioid pattern).

 

Our brains have an ability to "focus" on sounds in a live environment, especially where we can see what we want to hear, but once it's recorded, you really lose most of that ability. Stand in the middle of the room, close your eyes, and just listen to everything going on around: that's what you're recording. Other voices, traffic noise, HVAC noise, EVERYTHING is recorded. Makes it very very hard to separate out specific sounds later.

[Guest]

you have lost nothing from the job so just walk away.

 

 

and about signage. you say it might warn the offenders off. is that not what you want as an end result

 

I want to talk about the technical concern of syncing sound and video thats all.

 

The issue is specific to the recorder used and how it is set up.

 

You are correct that to record in an acceptable manner you are best to test the recorder/mic combination.

 

The issue with this type of work is that it is normally based around the front door of the property, so it will be likely that the normal day to day conversations of the family will also be recorded so it will be best if the family are advised of this.

 

The 3G transmission issue is not a concern. It will be slow to review images and even slower to download full resolution recording whether audio is there or not.

 

Legally you are have no concerns. The Council has a code of practice and the use of audio recording will be forbidden by this (relates to the ICO CoP for the use of CCTV). Any recordings will however be admissable in court.

 

The only only exception is if there is an RIPA authorisation is place. This also applies if the Police install the kit (same rules).

 

There is no licience you can get to allow audio recording or covert installation is the UK.

 

The main danger here is the political backlash for the Council if this type of operation come to the attention of the press, especially after the Birmingham project.

 

Regards

 

Ilkie

[Numb-nuts 1]

Thanks for that. This confirms what I thought would be the case, an omnidirectional mic (like the one I am loaning) will be eminently suitable in this case. I have advised my friend to place the mic under the window sill of the property on the 1st floor. The family that are being victimized are suffering regular verbal taunts, recording this combined with footage will be powerful evidence because it will give a fuller picture of the offenses being committed.

 

I have experimented with the mic and DVR and above 12fps there is no problem with syncing sound and video. The only problem is if there is a prevailing wind across the mic (never expected that) and this is easily solved by masking the mic with a foam wrap.

 

All sorted done and ready to go. Thanks all

[Numb-nuts 1]

The setup has been installed and apparently it's all been set up in a covert way.

According to my friend, the mic was installed wrapped in foam and housed in a

boiler flue housing glued, (yes glued) to the wall and it works way better than was

expected. All that remains now is to wait and see if a big fish can be caught.

 

Apparently the family, that are subject to bullying from their neighbourhood youths

were so grateful that the father of the house was in tears. I hope he doesn't think that

surveillance is a complete solution, it's just a means of gathering evidence, it's not a

one stop solution in a box to the trouble they have been suffering.

 

I was told that apparently a magistrates warrant was required to record covertly and it

was granted as result of two years of police reports of harassment. The council's policy

is to prosecute ringleaders, sending out a stern warning to others that might consider

this kind of behaviour . This is a council run housing estate (project) the offenders can

be evicted from their homes if they are in council run housing. Ringleaders can also be

subject to a "restraining" order which could land them in gaol (jail) if they break the order.

 

I am interested to see what happens now but unfortunately unless I hear about it in the

media my friend cannot disclose any evidence to me for legal reasons.

[tomcctv 190]

The setup has been installed and apparently it's all been set up in a covert way.

According to my friend, the mic was installed wrapped in foam and housed in a

boiler flue housing glued, (yes glued) to the wall and it works way better than was

expected. All that remains now is to wait and see if a big fish can be caught.

 

Apparently the family, that are subject to bullying from their neighbourhood youths

were so grateful that the father of the house was in tears. I hope he doesn't think that

surveillance is a complete solution, it's just a means of gathering evidence, it's not a

one stop solution in a box to the trouble they have been suffering.

 

I was told that apparently a magistrates warrant was required to record covertly and it

was granted as result of two years of police reports of harassment. The council's policy

is to prosecute ringleaders, sending out a stern warning to others that might consider

this kind of behaviour . This is a council run housing estate (project) the offenders can

be evicted from their homes if they are in council run housing. Ringleaders can also be

subject to a "restraining" order which could land them in gaol (jail) if they break the order.

 

I am interested to see what happens now but unfortunately unless I hear about it in the

media my friend cannot disclose any evidence to me for legal reasons.

 

 

 

 

are you a SIA company

[Numb-nuts 1]

I am not, in fact I have no idea what the SIA is but I am guessing it is some kind of industry association or accreditation.

 

No just an enthusiastic user and I am friends with the guy who installs the rapid deployment CCTV

for the local authority. He's not trained to any particular degree in CCTV just that he has the duty

to place the G3 DVR and a camera at the required properties. His main job is with the Anti Social

Behaviour team. Incidentally, they don't install a monitor either since what they capture is subject

to data protection and cannot be displayed in a place where they have no control over who can view it.

 

The things you learn eh? That's why I joined this forum to learn more about CCTV so far I have learned a lot

of basic stuff and have loads to learn. I have helped one or two friends with CCTV at their homes but mainly

because they themselves are completely techno-phobic.

 

I love a challenge but some of the schemes the professionals discuss on here have me reeling with confusion

at the moment.

 

My latest achievement was to blow a camera by plugging in a live DC cable and making a short, not easy to do. Expensive too.