In a previous post I wrote about using the UT-100C DVB-T modulator on linux and I promised to follow up how to use the modulator with live video sources. In this post I am going to describe how to setup the modulator on a Raspiberry Pi equipped with a RaspiCam camera module, effectively turning the Pi into a live HDTV transmitter.
The setup can be made small enough to be carried by a medium size drone and the range can be increased using power amplifiers. If you do that be sure to comply with the radio regulations applicable in your country. In particular, transmitting with significant power in the UHF TV bands will most likely get you into trouble. Your best bet is to get a ham radio license and use the 23 cm band.
The setup I am using performs the following tasks:
Capture H.264-encoded video from the camera using the raspivid application.
Convert the H.264 bitstream to constant bitrate and DVB compliant MPEG-TS stream using ffmpeg 2.2.2.
Send the MPEG-TS stream to the UT-100C modulator using tsrfsend application.
In my own setup I also use a 20 dBm power booster to increase the range.
The idea for this setup, in particular for using the latest ffmpeg for MPEG-TS generation, comes from Evariste F5OEO who posted it on the Viva DATV forum. In fact, he has made a complete Raspbian image available for download for those who want a quick and easy way to get started. While his image works well, it will limit you to the software available at the time when he built the image.
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