Contest numbers and another webcam

Discussion about this major DATV Project. See https://wiki.batc.org.uk/The_Portsdown_Transmitter
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g8lce
Posts: 350
Joined: Sun Dec 06, 2015 10:26 am

Contest numbers and another webcam

Post by g8lce » Sat Sep 26, 2020 7:03 pm

I have three DATV receivers monitoring on one web page. When I transmit from my Portsdown 4 the contest numbers they show a black line on the bottom of the commercial RX, nothing apart from a pink band on my Echostar 3000 but are OK on my Comag SL60.
contest numbers.GIF
contest numbers.GIF (1.07 MiB) Viewed 1195 times
I also found that pluging in an old webcam it worked when I selected compvideo as source!!
webcam not compvid.GIF
webcam not compvid.GIF (1.38 MiB) Viewed 1195 times

I know the webcam is not supported (a logitech 3000 ) but it has the same black band on the Tanberg Alteria commercial RX

Martin G8LCE

G8GKQ
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Re: Contest numbers and another webcam

Post by G8GKQ » Sat Sep 26, 2020 8:21 pm

  • The Black line is down to how your receivers choose to display an image that is not the same aspect ratio as their display. The Comag expands it to fill the screen, and the (very old) Altea RX fills the longest dimension and keeps the pixels square, then fills the remaining space with black.
  • The missing picture on the Echostar is because the transmitted digital bitstream from the Contest Caption is not perfect, and the Echostar can't cope with the minor errors.
  • The switching between sources on the Portsdown is easily confused, particularly if you connect video sources after boot. It does not support "hot-plugging". MPEG-2 encoding is more tolerant of non-supported cameras than H264.
Portsdown is not perfect, but it does provide an easy and cheap route to get on the air with Digital ATV.

Dave

g8lce
Posts: 350
Joined: Sun Dec 06, 2015 10:26 am

Re: Contest numbers and another webcam

Post by g8lce » Sat Sep 26, 2020 10:57 pm

Hi Dave,
I know it is not perfect but that makes it more fun to find all the edges of it's software. I know how much work is put into the software and answering all the queries.
I have a RangeRover Evoque which was one of the first petrol ones in Cornwall and has all the optional extras. I think I have almost found all the software problems that it has and the 'interesting' novelties. Considering they spend thousands of hours and lots of money on producing them there are still odd things that happen. If a wheel sensor fails then it thinks it has stopped so why do you need ABS or power steering? (even going around corners at speed)
Why do you need a small auxillary battery hidden away that fails after 5 or so years and causes the dashboard to light up and tell you to stop as your gearbox is faulty? ( it is not ) The other things I have found could fill a book ( bit boring on an amateur radio forum though! ) The bells and whistles are nice like the self parking and the road following headlights. Similar to the bells and whistles you are adding to the Portsdown 4. The way it will not transmit when the wrong things are selected is similar to the way the handbrake stays on if the drivers door is open ( but an indication that that is what's causing the problem would have helped while trying to pull a boat up a slipway while hanging out the door looking back!)

It is still my favourite car just as the Portsdown is my favourite piece of amateur radio equipment. ( Portsdown 4 )

I will continue to push the Portsdown 4 to the limits and bang my head against the wall trying to get all the possible bits to work. Still working on the Pluto and Langstone.
Limemini, Pi cam, USB video in and RX with Minitioune V2 all work really well, but I want it to do more!!

Keep up the good work

Martin G8LCE

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