Subscriber Discussion

Help - 100% Syncd Audio / Video "Movie Quality"

We have a customer requesting "100% synchronized audio and video" which they described as "movie style". Is there any product in the security market that would be able to do this? Anyone have any experience doing a lot of aaudio? I have done some and depedning on the system it's close to being sync'd but always a little off.

I researched this a few years ago and the only VMS I tested at the time that really syncronized audio and video was DVTel Latitude. I don't know if any of the others have gotten any better since that time. When I was doing my testing, most of them were terrible. Some were out of sync by 2 seconds or more.

Your customer wants a camcorder, not a CCTV camera.

Are you implying that synchronization issues are typically a problem of the surveillance camera not the recorder? If so, why? Is there certainly inherent weakness in surveillance cameras's capture / handling of audio?

I've seen audio/video sync problems with H.264 and DivX-encoded movies on my computer. I think it's more inherent weaknesses in some codecs. The DV/miniDV cameras we used to use never had A/V sync issues, and I've never seen sync go off with the AVCHD format my current mini camcorder uses.

Aside from that, the VMSes that I've actually looked at it, audio and video are stored separately, a practice which practically invites sync problems (I don't know if this is the case many, most, or all of them, just on the couple that I've actually looked at how the files are stored).

That said, if the customer wants "movie style video", I'd tend to agree, he should use a "movie style" camera, not a security camera.

I won't have enough experience on this across enough equipment to make a blanket statement. However, the customer appears to be asking for a feature which is of primary importance to one product set (camcorders) and of secondary importance at best to another product set (CCTV).

Most cameras seem to embed the audio directly into the video stream, at least when we're talking about modern cameras, h.264, etc. The modest number of cameras I've tested from major players (a couple of Axis cameras, a couple of Dahuas under various names, 2 no-brand units) did a good job of creating an audio/video stream where the sync was not noticeably off, about as good as my Tivo.

I think the big variable in this would be how the VMS server/client handles storing and replaying the audio/video sync. Additionally, you have to factor in future software updates potentially breaking this, unless both the VMS and camera vendors list audio/video sync as one of their top features or selling points. If it works today, but not in 1 year, will you have recourse with the vendors to get it resolved?

Meanwhile, there are 2000 camcorder products out there designed to solve this exact problem.

Thanks all. Audio is always a pain especially when the customers demands are as high as this.

Years ago I helped solve the same problem for Si's looking to handle custodial interview room applications in law enforcement settings. The best product (in the security industry IMO) at the time was a Sanyo MPEG-2 based DVR (DSR-M810) we developed a special SQL based windows app for the non technical user that allowed easy case management and file storage options. When Sanyo went away we worked close with 3xLogic engineering to tweak our user application to integrate with the 3xLogic Vigil hybrid platform. We have achieved solid synch results at least for 'law enforcement' applications using analog or IP cameras the trick is we always land the analog audio signal on the capture card audio inputs. The IP systems I helped out with typically were on a dedicated network segment so traffic was typically not an issue. The best alternative to the hybrid multi channel DVR that I can think of is right out of the A/V world I have reccomeded product from Data Video which is based in So Cal their base product accepts standard NTSC video and analog audio and encodes directly to AVI. The 3xLogic recorder encodes in h.264 which as others has stated in this thread stores the video and audio seperate, it stays that way in the export process unless the user selects AVI export. The Data Video product looked good to address the post recording editing requirement that city had asked for. Most editing applications ingest the AVI files straight away.