Video Capture Input


13 posts
by kkman20xx » Sun Mar 11, 2012 1:08 am
OK, I know that the broadcom 2538 SoC H,264 encoder is not covered by the license agreement in Raspberry Pi, so I am talking about NTSC/PAL video quality capture. I understand that you can use a USB video capture device with Linux which is good enough resolution from the source video.

My question is:  Is there a direct interface (or to fashion one) to connect to the Pi so that it can skip the USB part?  I heard there are mention of a camera interface there somewhere so is that available on the GPIO pins?  I only need to capture from 1 camera.

Applications includes: Homemade IP camera, Security camera, FPV DVR, general DVR, small Skype net device etc etc.
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by jamesh » Sun Mar 11, 2012 8:52 am
Camera interface is only available to the GPU itself. I think USB or GPIO is your only options, and GPIO probably isn't fast enough for video.

So, USB device is your best best at this stage.
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by kasperl » Sun Mar 11, 2012 10:32 am
Note that there are some USB devices that to MPEG2 encoding on chip, making the capture a matter of writing to disc. There's probably some that to H264 encoding as well.
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by arm2 » Sun Mar 11, 2012 3:29 pm
The foundation has said they expect to offer the R-Pi with a camera fitted, presumably it will come with support for the broadcom H,264 encoder!
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by mahjongg » Sun Mar 11, 2012 5:09 pm
the Raspberry PI (model B) contains a 15-pin MIPI Camera interface (CSI) connector, for a typical mobile device camera module, But at the moment the CSI interface is unsupported, (by software) but the foundation is planning to release a camera module for it, sometime in the near future.

Pinout of this CSI connector isn't available at the moment though.

More info (but not much) can be found at the RasPI wiki.
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by jamesh » Sun Mar 11, 2012 6:25 pm
Actually the interface is fully supported - what we don't have is a camera module and daughter PCB to attach it to the RaspberryPi (and depending on whether we have already written drivers, there may be some work required there). The software for the camera is all on the GPU - so driver work and tuning needs to be done by the Foundation or Broadcom - I've had plenty of volunteers at Broadcom, so manpower isn't a problem once the module is chosen.
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by Gert van Loo » Sun Mar 11, 2012 10:01 pm
I have talked with the leader of the camera team. Yes, he and several of his colleagues are willing to put in some extra (evening) hours to help the Raspberry-Pi. Only problem is an adapter board. We can't make one yet as we need the connector spec from the Raspberry-Pi foundation. I will ask for that next week, but I am also busy with the Gertboard (Oh.... Almost forgo: I also have a full time day job.)
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by Burngate » Mon Mar 12, 2012 6:06 pm
I can see at least the tip of the iceberg of the problems needing sorting before a camera becomes available. However I can also understand that there are problems I don't know about (unknown unknowns versus known unknowns - who said that?)

It might be of interest to see a picture from an "untuned" camera side by side with one from the same camera after "tuning"
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by kkman20xx » Mon Mar 12, 2012 7:56 pm
I guess it will be a while before the camera interface is available to us then.  What I am wondering also is that the availability of cameras with the CSI interface and prices.  Also that CSI interface will need a converter of some kind to conver say a composite video input to CSI if it is not directly connected to a camera. Well, USB adapter for me in the mean time.
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by Smartybones » Mon Mar 12, 2012 8:28 pm
kkman20xx said:


OK, I know that the broadcom 2538 SoC H,264 encoder is not covered by the license agreement in Raspberry Pi



I know it isn't covered by the licence, but I bet a pound to a penny that within 12 months there will be some sort of modification detailed somewhere on a unofficial raspberry resource website to enable and provide drivers to use it.

the fact that the broadcom 2538 chip is only usually available to people people buying it in the millions, getting hold of one from a raspberry pi is not the silliest of idea, the only way to get hold of similar chips in small numbers is to buy hardware that have used the chip, and pull it from the board. When you usually find them in mobile phones, then that can be prohibitively expensive if you are just going to strip the product.
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by kkman20xx » Mon Mar 12, 2012 8:56 pm
Well, we will probably have to wait for the user base to increase before more hardware, software supports and "hacks" available.

Oh, Found a chip that does HDMI-CSI but could be expensive.

http://www.toshiba-components......358743.pdf
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by jamesh » Mon Mar 12, 2012 9:42 pm
Burngate said:


It might be of interest to see a picture from an "untuned" camera side by side with one from the same camera after "tuning"


I'll see what I can do - it's really quite astounding.
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by jamesh » Mon Mar 12, 2012 9:43 pm
Smartybones said:


kkman20xx said:


OK, I know that the broadcom 2538 SoC H,264 encoder is not covered by the license agreement in Raspberry Pi



I know it isn't covered by the licence, but I bet a pound to a penny that within 12 months there will be some sort of modification detailed somewhere on a unofficial raspberry resource website to enable and provide drivers to use it.

the fact that the broadcom 2538 chip is only usually available to people people buying it in the millions, getting hold of one from a raspberry pi is not the silliest of idea, the only way to get hold of similar chips in small numbers is to buy hardware that have used the chip, and pull it from the board. When you usually find them in mobile phones, then that can be prohibitively expensive if you are just going to strip the product.


Problem is that the 2835 needs a specific build of software for the Raspi with the codecs statically linked in. You cannot just drag an image from a device which already has the codec.
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