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FreezeTile
Posts: 34
Joined: Thu Apr 05, 2018 6:39 pm
Location: Scotland

The composite video's gone all funny

Wed Oct 31, 2018 12:37 pm

Here's a Halloween horror for you - I'm trying to get composite video working on my Pi so I can use it on an old CRT TV, but when I plug it in, all I get is this.
DSCN0367.JPG
DSCN0367.JPG (98.41 KiB) Viewed 337 times
Any ideas?

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DougieLawson
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Re: The composite video's gone all funny

Wed Oct 31, 2018 1:07 pm

Wrong mode or your signal and ground are swapped.

The RPi defaults to NTSC 480i unless you tell it to do otherwise.
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rpiMike
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Re: The composite video's gone all funny

Wed Oct 31, 2018 1:20 pm

Set sdtv_mode=2 in /boot/config.txt for PAL

https://www.raspberrypi.org/documentati ... t/video.md

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FreezeTile
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Location: Scotland

Re: The composite video's gone all funny

Wed Oct 31, 2018 3:32 pm

DougieLawson wrote: Wrong mode or your signal and ground are swapped.

The RPi defaults to NTSC 480i unless you tell it to do otherwise.
rpiMike wrote: Set sdtv_mode=2 in /boot/config.txt for PAL

https://www.raspberrypi.org/documentati ... t/video.md
The cable I bought was advertised as being compatible with the Pi, so that can't be the problem. I tried changing the config file:
Screenshot 2018-10-31 at 15.17.36.png
Screenshot 2018-10-31 at 15.17.36.png (120.73 KiB) Viewed 273 times
but I'm still getting the same fuzzy picture. What now?

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DougieLawson
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Re: The composite video's gone all funny

Wed Oct 31, 2018 3:36 pm

Check that cable with a continuity checker (or a multimeter on resistance).

https://www.raspberrypi-spy.co.uk/2014/ ... ideo-jack/
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Burngate
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Re: The composite video's gone all funny

Wed Oct 31, 2018 6:39 pm

FreezeTile wrote:
Wed Oct 31, 2018 3:32 pm
DougieLawson wrote: Wrong mode or your signal and ground are swapped.
The cable I bought was advertised as being compatible with the Pi, so that can't be the problem. I tried changing the config file:
Composite video has sync pulses that are blacker-than-black
That first picture is showing white sync pulses - the broad vertical white stripe is the line sync, the narrow horizontal white stripe is the vertical sync
So your cable isn't compatible, whatever the advert says.

drgeoff
Posts: 9344
Joined: Wed Jan 25, 2012 6:39 pm

Re: The composite video's gone all funny

Wed Oct 31, 2018 9:22 pm

Burngate wrote:
Wed Oct 31, 2018 6:39 pm
FreezeTile wrote:
Wed Oct 31, 2018 3:32 pm
DougieLawson wrote: Wrong mode or your signal and ground are swapped.
The cable I bought was advertised as being compatible with the Pi, so that can't be the problem. I tried changing the config file:
Composite video has sync pulses that are blacker-than-black
That first picture is showing white sync pulses - the broad vertical white stripe is the line sync, the narrow horizontal white stripe is the vertical sync
So your cable isn't compatible, whatever the advert says.
+1. Absolutely, definitely, certainly, without a doubt the cable is not wired appropriately for the TRRS socket on a RPi.

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FreezeTile
Posts: 34
Joined: Thu Apr 05, 2018 6:39 pm
Location: Scotland

Re: The composite video's gone all funny

Wed Oct 31, 2018 9:25 pm

drgeoff wrote:
Burngate wrote:
Wed Oct 31, 2018 6:39 pm
FreezeTile wrote:
Wed Oct 31, 2018 3:32 pm

The cable I bought was advertised as being compatible with the Pi, so that can't be the problem. I tried changing the config file:
Composite video has sync pulses that are blacker-than-black
That first picture is showing white sync pulses - the broad vertical white stripe is the line sync, the narrow horizontal white stripe is the vertical sync
So your cable isn't compatible, whatever the advert says.
+1. Absolutely, definitely, certainly, without a doubt the cable is not wired appropriately for the TRRS socket on a RPi.
Bugger! >:-(
Oh well.

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