I am thinking of developing a software solution to send images from digital cameras to a mobile phone.

I have seen DVRs with 4-8 channels selling as kits. They allow remote access viewing via a mobile device.

How are the images streamed from plugged in DVR to router to mobile?

Is this type of service reliable? If we assume that the internet connection is OK are the images reliable to view in real-time on a mobile phone?

Is it possible for multiple users to access the same stream?

  • The part about IP resolution is certainly not on topic, so I've removed it. The parts about how to stream video are possibly on-topic, so I'll leave it up to the community if they want to close or not. It might help if you included more detail about what you are hoping to accomplish by streaming from a camera directly. The workable solutions are very different depending on if it is needed for smooth video or security purposes and may also impact if it is on topic. – AJ Henderson Mar 4 '14 at 18:34
  • @AJHenderson Hi, thanks for that. I was struggling to find the right forum. The IP resolution was the most important part for me. I can delete this question myself in a minute. Do you know of a correct forum here to post that type of question to? Thanks – Andrew Simpson Mar 4 '14 at 18:40
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    The IP resolution would probably be good on super user. There is no difference between IP resolution for video reasons than for say a chat program. – AJ Henderson Mar 4 '14 at 18:44

There are numerous different possible ways for a video stream to be done. Generally video is streamed over a UDP streaming format such as RTMP or something similar. It can also sometimes use a series of individual pictures (particularly common when refresh rate is not that high, such as IP security cameras.)

In the case of a home device acting as the source, a connection would have to be made between the client device and the home device, possibly using a third party server to help get across any firewalls or dynamic IPs. The information would then be streamed the same way as any live stream technology. The video would have to be encoded on the stream server and then passed to the client.

The reliability of the service would depend entirely on Internet connection speed of both the client and the server. Streaming video at any kind of significant quality is a very bandwidth intensive activity and most residential connections are not capable of the necessary upload speeds for high quality video, though standard definition may be possible. Higher end connections can cover HD speeds though.

As for multiple users, within a local network, multicast can be used to distribute UDP packets of a stream to multiple users, however, across the public Internet, multicast is not possible. An individual connection has to be made to each client and the content must be sent once for each client. (Two clients takes twice the bandwidth requirement of one.) With sufficient bandwidth, there is no reason the packets can't be independently streamed to both, but that goes beyond the limits of just about all consumer Internet connections.

  • excellent. It is what I wanted to know. – Andrew Simpson Mar 4 '14 at 18:45

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