HDMI to CSI-2 bridge

Discussion about this major DATV Project. See https://wiki.batc.org.uk/The_Portsdown_Transmitter
KA5BBC
Posts: 161
Joined: Thu Jun 28, 2018 6:59 pm

Re: HDMI to CSI-2 bridge

Post by KA5BBC » Fri Oct 09, 2020 8:41 pm

Dave..
I have the day off tomorrow and will test various input devices including SD inputs. I have multiple options I can use including Blackmagic card outputs, standard converters, etc for both NTSC and PAL. I will stream my tests and report back here on each.
Andy, KA5BBC/MM0BQV

SkyVision
Posts: 75
Joined: Fri Jan 24, 2020 1:51 pm

Re: HDMI to CSI-2 bridge

Post by SkyVision » Mon Oct 12, 2020 1:14 am

Hi KA5BBC

I posted on the CSI-2 a year ago
viewtopic.php?f=103&t=5738&p=21408#p21408
It does work with limitations
If someone could figure out the sound it might get some traction, but no good for reduced bandwidth unless it could be scaled down
Which defeats the purpose
That seems to be the main focus of the BATC, reduced bandwidth

Cheers Roger VK5YYY

KA5BBC
Posts: 161
Joined: Thu Jun 28, 2018 6:59 pm

Re: HDMI to CSI-2 bridge

Post by KA5BBC » Mon Oct 12, 2020 10:16 am

Roger.
I have pulled apart the hardware specs and standards for CSI-2 and unfortunately it does not have any provision for sound, the RPi 3 & 4 only uses two out of four available lanes and the compute module is the only one that uses all four hence the reduced resolution and frame rates available. There is always the option of an audio extractor device on the HDMI input routed to the analogue audio input or a separate microphone.

As for device selection and resolution switching. I have not completed my tests, I have only had a half-hour at about 0400 before I go to work each day, with various devices yet however implementing a simple HDMI switch, HDMI splitter, HDMI quad viewer, and a couple of different standards converters (with and without scaling) I have yet to have an unusable image when fed with everything from 480 through 1080 both PAL and NTSC. With one standard caveat that HDCP enforcing devices do leave you with a blank screen - so no Apple TV inputs which is a shame as I was going to use that in a quad viewer to show weather radar during tornado season.
Andy, KA5BBC/MM0BQV

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