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Known Limitations for Hardware Capture Agent

This is a listing of known limitations for the Hardware Capture Agent in particular. Many of these limitations are actively being worked on but this article will give an idea of what we know about as well as possible workarounds.

  • The hardware capture agent is able to capture from only 1 USB webcam at a time because webcams, in general, will use the entire USB bus.
    • There is a workaround if you request an additional PCI to USB card so that 2 webcams can be captured at the same time but this is only available per request because a custom build of our software and hardware has to be distributed.
  • If you plugin a USB2 webcam device into a USB3 slot the capture detection and captures in general will fail and/or lock that device/drive. In order to release the device a reboot is required but no other side effects have been found.
  • The system is able to handle situations where webcams or capture cards peripherals are unplugged (it will fabricate the user configured signal). However, only with webcams, if the device is plugged back in the capture won't resume for that device. The capture card video signal resume capture works without issues. We expect this to be resolved in the next major release of the capture agent.
  • Webcam audio drivers, because of how the standard linux drivers use the entire USB bus, introduce a latency for audio hot detection. The common use-case is plugging in a webcam with audio; the user will see the video device detected rapidly but the audio component won't be detected for 30 sec to 2 min later. We expect this to be resolved in the next major release of the capture agent.
    • There is a workaround if you don't see the audio device within the time you expect then click re-detect devices. This will work most of the time as it clears the internal configuration and attempts to redetect.
  • The capture card (through DVI or HDMI) we have does not support HDCP. If you have a device that is plugged into the capture agent and it uses HDCP it WILL NOT be able to capture from that device. We plan to beta test a new version of our capture card, with our vendors, that may be available sometime in the future which will allow us to capture from HDCP enabled devices.
  • If you notice a flash or cycle of colors that overlay your video from a webcam that is absolutely normal. Each webcam initializes in different ways and at different speeds. Some do a screen test which is what you are seeing. Since we don't know when the webcam is 100% complete testing we sometimes intercept the video while it is initializing.
  • We support many webcams but not all of them. For an exhaustive list of we are able to support reference: http://www.ideasonboard.org/uvc/
  • A long lecture's video file can be very large depending on the dimensions, fps, quality level, etc. A large video file isn't an issue to store locally but when you use a publisher that only supports HTTP there is a risk that the video file (and it's related assets) won't complete the upload. There isn't any limit on our side and we won't timeout while we are posting but, depending on the publisher and the technologies they use, there could be limitations once the file is around 1 GB, typically. For the publishers that support FTP we attempt to use that first before HTTP because it is more stable, easily resume-able, can handle very large files, etc.
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