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Showing posts from March, 2017

Troubleshooting Video Streaming

Casting About Video multicast routing usually 'Just Works'.  Occasionally it doesn't work at all, or the video streams for a few minutes only and then one is left scratching one's head... To find out what is wrong, one has to know how to analyze a playback streaming problem when it happens. Here is something to read on streaming, multicasting and the Internet Group Management Protocol (IGMP):   Multicast Version Sometimes is is necessary to use a specific version of IGMP to get things to work. One can force the IGMP version in the /proc/sys/net/ipv4/conf/eth0/force_igmp_version to 0 (auto), 2 or 3. Multicast Routing The multicast address subnet is the 224.x.y.z address range.  For routing to work at all, you need a multicast route, set with a command like this: # route add -net netmask dev eth0 That is if your ethernet port is eth0.  Mine is enp0s26u1u1 at the moment - I

Saving the trees - PDF signatures

How to stick a signature graphic into a PDF file, without having to print it first: A word of warning first Don't stick your signature into a MS Word document, since anyone with 2 brain cells can alter it. Also don't use your usual signature - Make a special scrawl for office use. Print the file to PDF with Foxit Reader If the file isn't in PDF format already, open your MS Office document with MS Word on Windows. Print to a file and select PDF format. If you cannot print to a PDF, install Foxit Reader: Make a signature graphic with transparent background using Gimp Make a signature graphic with transparent background: Take a pen, scrawl on a piece of paper. Scan it. Use a real computer - Linux, BSD or Mac: apt install gimp xournal pdfshuffler Open the scan file with Gimp Crop it Select the white background with the eye dropper Click Layer, Transparency, Colour to Alpha Click File, Export, signa