I want to use Rasbery Pi for lecture capture.  Please advise how to do it.

Are you wanting camera (Getting to know the Raspberry Pi Camera and Pi Noir ) and microphone (A Slice of Raspberry Pi: Adding an Audio Input Device )?

Clem

Yes, I would like to record both audio and video.  I could use an external camera source and a line source for the audio.

What then is the best solution for me?  Do video surveillance systems record audio in sync with the video?

Sounds like your budget is your top consideration. Although video surveillance systems look attractive, audio is low quality if they exist. Are all 20 classrooms running at the same time? Do all need recording? Do they start same time? Is the instructor in a fixed location or moving around? Do they use blackboards or video projectors? A effective system ned due consideration to many factors.

Clem

There isn't a (known) solution with RPI, unless you're prepared to design it.

You didn't specify if you wanted this for recording lectures in a high quality, or a lower quality for surveillance purposes.

Expect to pay at least $10k-$20k for the recording system alone, and perhaps a further $10k for the 20 cameras, if you want

to record audio and video. (This is surveillance quality, barely usable for a lecture theatre multi-camera recording solution).

Otherwise, go with an analog camera system and a hard drive recorder at a very small fraction of this cost, but it won't

record audio from all cameras usually, and the frame rate will be very poor (as will resolution - but 'good enough' for basic

security).

Yes, the budget is a constraining factor.  The lecturer would be moving so I guess I will need a tracking camera.  All 20 classrooms will be running at the same time.  All of them need recording as I want to give the students the opportunity to go back home and refer to the lecture in case they want tor revise the same.  They all start practically at the same time but this could vary.  Audio quality can be good as I would take the line out of my audio mixer for the feed.  The teachers use the conventional black board 95% of the time and projectors rarely.

Please watch this video

https://www.youtube.com/watch?v=fr6-6EHl-bo

Wow. Then expect the budget to increase by an order of magnitude, $200-$300k would not be unreasonable!

Alternatively, you could train the teachers to present using a PC, and then use something like webex..

The teachers could be trained to use laptops for presentation but all may not agree to.  Further, this process takes time.

You've described a couple of different scenarios. In the video, they showed the setup that Clem initially proposed. A raspberry pi, with a camera in a microphone in a room. That is pretty easy to setup.

You then added the complexity of sending that video/audio data to a central location to be controlled by an operator. Clem pointed out the the Pi probably doesn't have the IO bandwidth for that.

It would be inexpensive to setup 1 pi per room, then transfer the recorded video after the fact via network.

You could easily mimic the setup they show in the video, and compromise on the central control and data capture.

Mike

So there's your answer(!).

If you think that solution is available for download or purchase, why not obtain or purchase it?

Otherwise, you'd have to either design a solution using the Pi, or expect to pay what an off-the-shelf solution costs.

I like this suggestion.  However, the classrooms continue for 4 hours and I wonder how long a footage can be captured by the raspberry PI.  Secondly, how do I get the Pi to start and stop recording.  I guess I could feed the rasperry PI and audio feed from my mixer to enable high quality audio being recorded too.  I am open to all options.

I like this suggestion.  However, the classrooms continue for 4 hours and I wonder how long a footage can be captured by the raspberry PI.  Secondly, how do I get the Pi to start and stop recording.  I guess I could feed the rasperry PI and audio feed from my mixer to enable high quality audio being recorded too.  I am open to all options.

I think I've answered a couple of the questions. Duration of recording will be determined by the quality of the recording. 64gb and 128gb sd cards are available.

http://studiopost.com/contact/tech-specs/calculating-disk-space-requirements

That is a link to storage requirements for recording hd video.

You might have to compromise on the quality, but if this is for web quality viewing it may be doable.

Mike