James - I have been directly involved in many interview system installs and designs going back several years now they started with analog using MPEG-2 recorders with an alarm input for start / stop control and a dedicated user interface that ran an instance of MSQL creating a GUI to what amounted to a file management system once an interview session was exported off the original DVR. The original MP2 file made for an easy path to a DVD export that could play in a standard consumer player.
The demise of that recorder forced a switch to a newer multi channel hybrid platform typical of many in the market today i.e. compatible to a wide variety of IP camera streams.
We found that having a physical start / stop switch for each room is useful for this application especially if the swicth also supports a status feedback such as a lamp or LED driven by the recorder going into record (Alarm) mode for a given room. In the systems that I have advised on we still reccomend using a high quality microphone from Lauroe or Crown that outputs analog audio which is terminated on the hybrid DVR analog audio input terminals dedicated for each room.
The video is streaming across an IP link but the encoding and capture of the audio we have found the most reliable performance still happens when we land the analog audio on the DVR itself. We have started to see OK results on a system local to me that was specified Genetec for all cameras of which there are 51 in the system 7 channels are interview rooms with 6 being driven by a start / stop switch. We spent a great deal of time sorting out technical issues of encoding and capturing sound in this system. I was overruled when I suggested a seperate dedicated interview system.
In my experience the audio is a bit more crucial to the investigators than the video good levels are inportant (proper room placement is key) as is decent synch we typically dial the video recording down a bit usually between 24 - 27FPS for best results.
We have also taken the inquiry about deleting a recording session once it had been exported in both internal affairs and more typically child abuse investigations. The platform I am currently most familuar is like most security products i.e. specific blocks of recording data cannot easily be deleted without deleting everything else on the unit. In the case of IA they ended up with their own seperate single channel system seperate from investigations.
If live viewing was requested in the system we use the system thick client which does a good job of supporting local live views with good audio performance assuming IT folks were on board. We often ran into others in a department raising legal flags with respect to this type of A/V streaming across the LAN. I know it can vary widley across the country just be cautious. We have not experimented with a browser for this application.
We are also seeing some interest in a similar set up at a local community college in test and teach applications basically a big multi channel interview set up. I am currently scheduling training for non technical end users at the local CC now.
Hope this helps sorry for being so wordy...
