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How to build a Private phone network on VOIP using Asterisk PBX with Raspberry Pi and Mobile client

There was a need for an Organisation to build a phone network for use by their employees. Unlike the yester-years where telephony was analog and it required switching exchanges to route calls. The Govt or large corporations would set up Private Branch Exchanges (PBX) for this function. Now a days calls can be made digitally on the internet itself given that a server can appropriately route them to their chosen destinations. Voice over IP is used to digitally transmit packets over IP on the network to enable calling. There is a need for a VOIP server and clients that can talk to each other just like the old phone network. This can be easily achieved using robust opensource tools. Asterisk is an opensource PBX that has been around for a long period of time. Asterisk is an open source framework for building communications applications. Asterisk turns an ordinary computer into a communications server. Asterisk powers IP PBX systems, VoIP gateways, conference servers and other custom soluti...

Raspivid Modification to Display Custom Message as Annotation on Video Feed (Local/Stream)

  Raspivid Custom Annotations Raspberry Pi distribution is equipped with an executable called raspivid/raspistill which is used to capture and view video/still images from the RPI's CSI camera. The source code for this is available on the internet. It has various options like displaying video on HDMI, running TCP/UDP stream server, capability of reading encoded MP4 streams from the encoder, annotating the transmitted stream, automated still captures, effects, etc. Annotations like an OSD label can be provided on the stream being transmitted. Time annotations, etc can be enabled on the stream/video feed.  The only drawback is that annotations are updated every second on the feed. As there was a need to view various sensor information embedded in the video from a remotely operated vehicle, it would indeed be advantageous to extend raspivid capabilites. As a quick modification was intended, the relevant files were changed to use an IPC (InterProcess Communication) mechanism and a...