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Originally Posted by miroj When you say video do you mean camera / TV function .... that is just S-Video or Composite.
If you are saying that DVD playback is high speed serial bus then that is just PCM and whatever your DVD player at home pumps into the MPEG chip.
The speed signal blockers which allow the DVD to view all the time in W221 causes a malfunction in the reversing camera operation. It does not allow the camera to function when the reverse gear is selected.
The hack which allows the reverse camera to operate as a video input is something new.
There are no special ports on TV or Camera. IT is straight video. |
ok, lets compare... on US 221 model if you pull out the AGW (the box with the 6 disc player and pcmcia slot) and look on the back, you should see a 2+20 multi connector ( 2 MOST plus 20 pin mqs ) and then there are 2- 10 pin connectors (a non-standard square plug with 2 rows of 5 pins). the 2+20 connector carries power, gnd, rear camera composite video, aux audio input, and two sets of CAN bus connections. there is also a second video input pin that is not used on US models. one of the 10 pin connectors is used: it connects the AGW to the front display. on this connector the video is not composite, s-vid or even RGB, it is high speed digital similar to a PC DVI format but in typical mercedes proprietary format. the second 10 pin connector is unused on US models but is indicated in the reference manual that this is for the tv option. i cannot confirm that since thats not available in the US.
the US models up to 2007 were DVD audio only at the 6 disc in dash changer. for 2008 the changer now supports DVD video. when im talking about video in motion i pop a disc in the 6 disc in dash changer and it plays on the front (center) display while the car is in park. when you put the vehicle in gear video is disabled. the video from the in dash changer runs directly to the front screen over that same 10 pin high-speed connector... AFAIK on us models there is no pin to break out standard composite video from the in dash changer but i also havent looked much yet. the rear view camera is composite and enters the AGW unit via 2 pins on that 2+20 connector. from there its again over the 10 pin connector to the front display.
The ability to select both DVD in motion and rear view camera input is done via CAN messages. i can patch into the vehicle CAN network and interrupt and alter those messages to enable DVD playback while moving or the rear camera without issue. i have a prototype module (for 2008) that does this by itself now. switching in a seperate video source basically involves telling it to turn the rear view cam input on and then using an analog switch (4052) to switch the rear cam video signal for another.
i dont know if the rest-of-world 221's work differently, something like the other model tv tuners, where they have that additional green FAKRA connector that inputs the video signal. if they do then the setup to enable video would be a bit different but not a show-stopper. if i can get ahold of some bus logs for the euro model i can probably fix your reverse camera issue.