Discussions

MinimOSD and PAL

Posted by James masterman on April 3, 2012 at 6:35am

I have just bought a Minim OSD and got it all soldered up. I am running it on the ground rather than in the plane as I want to be able to see the OSD even if the video glitches when I am at long range.

 

I have encountered a strange problem that I am hoping I can get some help with. When I plug the OSD into my goggles or computer without an input video stream into the OSD, I can see the OSD perfectly with a black background. All of the information coming from the plane is there and it responds. Once I plug in the video feed from my video Rx, the OSD information just dissapears, all I can see is the video feed. It's clear, but there is no OSD information any more. As soon as I unplug the video input into the OSD, the OSD information reappears on my screen, with a black background.

 

I did some playing around, and it appears that the PAL signal being put out by the OSD is a PAL M type. Which is 60Hz and 15.750kHZ horizontal freq. I checked the specs of my PAL camera on the plane, and it is 50Hz with a 15.625kHz horizontal freq, also known as PAL N.

 

Could this difference by the cause of my problem? Is the minimOSD having problems syncing the camera feed to the OSD layer? Is there any way to fix this in the firmware?

 

Regards

JAmes

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Replies

  • Charles C Spencer III March 4, 2017 at 7:33am

    DO NOT connect a return wire from the osd back to the source. It confuses the video/osd....

    Regards,

    Charles C Spencer III


    James masterman said:

    Ok, some more investigating reveals this - If I plug the output from a DVD player into the MinimOSD, I can see the OSD display over the top of it. Everything works as if it was in the plane. If I put the output from my Duo5800v2 rx into the MinimOSD, all I get is the video and no OSD. If I unplug the video, I can immediately see the OSD layer against a black background.

    So the cause appears to be something in what the reciever is doing to the video output I guess. Or possibly the camera itself. The camera is a WDR700 from BEV RC (PAL camera). The resolution of these is quite high at 795x596, but close to a DVD.

    Is the chip unable to manage resolutions this high? What is the resolution of the OSD itself? Are there only certain cameras that work with MinimOSD? If so, this needs to be made very clear when buying one.

     

    If it is the receiver, does anyone know if it would be doing something special with the image? Don't they just output whatever the camera was outputing?

     

    I'd really appreciate some help on this.Are there any MinimOSD gurus out there?

     

    Regards

    James

  • Flying Buddha July 28, 2014 at 8:37pm

    Here we go again (with a solution)...with different set up, same issue. I loose video or my overlay when I plug in my gimbal. Heres my set up:

    Primary Battery (6.0 4s) powers my power plant (Y6) and the minumOSD (5v side) via the APM 2.6

    Secondary Battery (1.0 3s) powers my Gimbal, Video Tx and munumOSD (12v side) via the Vid Tx

    I loose my overlay or video when my gimbal is plugged in. But I found hitting the reset button on the MinOSD fixes the issue every time. I even tried powering everything up in different sequences and it seems to work. I also want to NOTE that I loose video signal on my GoPro if I dont do anything for a couple of minutes, but if I hit record my video pops back up.

    3701795672?profile=original

  • James masterman July 23, 2014 at 4:38pm
    This is a blast from the past! For me the problem was software. The early versions of the standard minim osd software didn't set the board to PAL properly, but any of the minimosd-extra builds of the last few years fixed that problem.

    I also power my board just on 5v from the autopilot only. There are two solder pads on the underside of the board that you need to add a solder blob to, to make that work, but it means the board keeps a lot cooler.
    • Paulo Melo > James masterman July 23, 2014 at 9:32pm

      Unfortunately not to everyone that blast from the past... i can still see recent posts regarding this issue, and mine is just another one one. Besides, in every single forum discussion about this, no one gives a solid answer.

      I believe i tried everything! Feed from 5v, feed from 12v, feed from 5v with power module, feed from 12v using ubec, feed from 5v and 12v  using external psu, tried the reset which didn't worked of course. Tried all firmware vesions, and i can verify that the firmware changes the board to pal. My minim osd is working properly, only the video overlays the osd layer. To me, in my case its a hardware incompatibility. I could check that in last resource some people solved the problem by replacing the camera. Even saw one guy with a sony nex 5 that solved the problem by replacing the cable's video converter by a non sony one. Lucky others have solved the issue doing the "dance".

      As i said, there is not one solution for everyone. I sent an e-mail to securitycam2000, seems that they know which cams are suitable for the job and not...

      • James masterman > Paulo Melo July 24, 2014 at 12:13am

        I agree it's a difficult issue to solve. Doesn't seem to be one particular solution that works for everyone. I'm not even sure the MAX chip is at the heart of it given how widely used it is.

         

         

  • MR60
    Hugues July 23, 2014 at 7:25am

    Hello ,

    I had also issues with flickering, using a Sony NEX camera, thus going through an AV converter hdmi->analog video.

    I first used a compact HDMI to AV converter board, specifically made for the Sony NEX. This never worked : always got flickering.

    I also thought it was a problem with minimOSD and tried various things without success. I then told myself that the cause was maybe elsewhere in the video chain. So I changed the HDMI-to-AV by another one and success! I do not know why this particular converter caused mimimOSD to flicker.

    • Paulo Melo > Hugues July 23, 2014 at 8:59am

      Im using a regular ebay board fpv camera, sony 700tvl. Any suggestions? Im almost giving up...

  • F. C. Bearsch June 29, 2014 at 6:15am

    Gabor, hopefully you can help me trace this problem, as I want to figure out what happened so I can mitigate it in the future. Had a working MinimOSD been using on Adrucopter 3.1.5 with minimosd extra 2.4 beta, solution to nonupdating data... Worked fine, 

    Then tried to get it to work on a Crius aiop running the latest release of megapirateng, connected it to the 3rd open serial, as the GPS and 3dr telemetry radios are using the other... Went through power up and good a scrambled screen...

    Rechecked the wiring and it is TX to Rx, power, ground to the blk... 

    Now I connect it back to the ftdi and computer I get just a black boot screen or nothing, seems if I hit the reset. On the board as it powers the back screen goes away and I just get video...

    I guess I could have a bad video chip, maybe when I connected the crius to the osd it scrambled the video, however can I fix this or is the board gone..

    I can still read, and load hex files, character sets, just nothing on screen, any ideas, I will document a fix if I find one.

    Plan on getting a few more minimosd's but will not connect it to the crius until I know what is going on

  • G.S. D.P. January 18, 2014 at 9:07am

    Hi, i have consumed many hours searching for the same problem... But fortunately i have ALWAYS OSD , but FLICKERING when using 700TVL camera... tested both signals on oscilloscope, seeing slight difference in frequencies (maybe PAL N/M as stated before..).. Also today tested the same camera on DJI Naza OSD, it produces the same problem but i am not sure if it is using MAX7456.. Searched the datasheet i noticed the VM1 register (video modes) which says about blinking...(some miliseconds, duty cycle etc...) Also noticed that in VERTICAL MODE... i have OSD field by field and NOT in every field... this produces the flickering... if i remove the video in all goes to normal with solid OSD... Maybe its a matter of setup but i haven't found anything yet in the source code...

    • Paulo Melo > G.S. D.P. July 23, 2014 at 3:09am

      Have the same problem!

      Wean i connect the video it overlays the osd info screen

      The reset after turning the camera on didn't worked for me.

      I have found that if i feed the osd on 5v side, using my regulated psu, i can get both video and osd for one second. That's the only thing i have achieved, after many hours on this issue. Any help on this matter will be appreciated.

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