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RCA composite video display

Posted: Thu Jul 26, 2012 1:36 pm
by ianhm
Hello all,

I have successfully installed raspbian and I am able to ssh into my Pi across my network. I do not at present have a monitor with HDMI so, instead, I am trying to use an analogue TV (PAL) via the RCA output. However, the resulting display is far from clean. There is obviously text and horizontal sync is fine but there are two black horizontal sync bars, the image blinks at about 4 Hz and is in two parts vertically overlapping. Do I have a fault or a config problem.

Regards,
Ian.

Re: RCA composite video display

Posted: Thu Jul 26, 2012 1:54 pm
by lb
Have you set the TV standard to PAL in config.txt? Some (older) TVs cannot handle NTSC timings correctly.

Re: RCA composite video display

Posted: Thu Jul 26, 2012 1:56 pm
by tdelany
You may need to create a config.txt in the /boot directory with the following in it:
sdtv_mode=2
See:

http://elinux.org/R-Pi_Troubleshooting# ... r_no_image

Tom

Re: RCA composite video display

Posted: Thu Jul 26, 2012 2:55 pm
by ianhm
Thank you for your replies and the solution.

/boot/config.txt is self explanatory really. Another case of RTFM on my part.

Thanks again,
Ian.

Re: RCA composite video display

Posted: Thu Jul 26, 2012 5:14 pm
by tdelany
As for me knowing the answer: my Grandfather used to say, "Even a blind squirrel gets an acorn once in a while." :D

Re: RCA composite video display

Posted: Sun Jul 29, 2012 11:44 am
by raspfly
My old CRT TV is working well with RP except that the resolution is too low and a lot of text / windows is out of the screen area. I have configured the config.txt file to use PAL. What else needs to be done ?

Re: RCA composite video display

Posted: Sun Jul 29, 2012 12:12 pm
by jdbennet
raspfly wrote:My old CRT TV is working well with RP except that the resolution is too low and a lot of text / windows is out of the screen area. I have configured the config.txt file to use PAL. What else needs to be done ?
Not much really. SDTVs have crap resolution. They only work at something like 640x480 (your phone, and PCs circa 1998 use a higher resolution lol)

Re: RCA composite video display

Posted: Sun Jul 29, 2012 12:29 pm
by drgeoff
raspfly wrote:My old CRT TV is working well with RP except that the resolution is too low and a lot of text / windows is out of the screen area. I have configured the config.txt file to use PAL. What else needs to be done ?
Have a look at the four overscan_left etc lines in /boot/config.txt. Uncomment the lines and adjust the numbers to stop the text/windows going out of the screen area.

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

Re: RCA composite video display

Posted: Sun Jul 29, 2012 12:52 pm
by portets
you can also change the framebuffer_width and framebuffer_height in config.txt. Making them bigger than your tv's resolution will make text smaller and blurrier, but gives you way more desktop space. Try something like:

framebuffer_width=800
framebuffer_height=600

if text is too small:

framebuffer_width=720
framebuffer_height=540

if text is still to small, the lowest that would still help is:

framebuffer_width=565
framebuffer_height=492

Re: RCA composite video display

Posted: Sun Jul 29, 2012 5:48 pm
by raspfly
I will try adjusting Framebuffer.
changing Overscan just increased or decreased the black border.
Does changing the framebuffer changes the size of the console window ONLY or it increases the amount of windows viewable on the screen ?

I also faced one problem, earlier when i used to right click on my desktop i could get an option (menu) to change the wallpaper etc but i clicked 'something' in that menu and now i can not see that menu any more. Rather i get another menu where i can click to exit openbox. How can i get the previous menu back ?

Re: RCA composite video display

Posted: Sun Jul 29, 2012 10:58 pm
by portets
It increases the viewing space for everything, except some fullscreen applications that make their own screen(like quake3 and other fullscreen 3d games). To compensate for the harder to read text, i messed with my theme so that everything is very dark grey and fonts are very light grey. I find this the most readable.

As for getting that menu back, I'd like to know as well ;)

Re: RCA composite video display

Posted: Tue Jul 31, 2012 1:27 am
by raspfly
I changed the frame buffer to 800x600 and its much better now. But still there is a lot of flickering. Is there any way to reduce that ?

I also faced another problem, earlier when i used to right click on my desktop i could get an option (menu) to change the wallpaper etc but i clicked 'something' in that menu and now i can not see that menu any more. Rather i get another menu where i can click to exit openbox. How can i get the previous menu back ?

Re: RCA composite video display

Posted: Tue Jul 31, 2012 3:59 am
by portets
Open a terminal and type:

Code: Select all

pcmanfm --desktop-pref
under the desktop tab, uncheck the box.

Re: RCA composite video display

Posted: Tue Jul 31, 2012 2:45 pm
by lb
It's not really possible to get rid of the flickering. SD TVs use interlacing, and always flicker. It is possible to somewhat reduce the apparent flickering by softening the image, but this reduces sharpness/resolution (obviously :)).

Re: RCA composite video display

Posted: Tue Jul 31, 2012 4:30 pm
by drgeoff
If the old TV is not too old it may be able to accept NTSC (525/60) which has a higher vertical refresh rate and thereby makes the flicker less visible. The downside is that 525/60 resolution is even less than PAL (625/50).

If the TV is even older it will not be able to decode the colour part of NTSC and will produce a black and white image with 'dots' in the coloured areas. It may also have a reduced height picture - you won't have to worry about vertical overscan :) .

If the TV is really old then the picture may roll vertically and will need a tweak of the vertical hold control (if an externally accessible one is provided.)

The insides of televisions are dangerous places. Never take the back off unless you really know what you are doing.

Re: RCA composite video display

Posted: Tue Feb 11, 2014 12:34 am
by Mindus
I have exact same problem with my raspbmc and old Rca connected tv. The resolution does not fit and i can't change it from settings I also tried framebuffer options in config.txt but it didn't changed anything. Do any of you have any other solution about it ? All i want is changing the resolution into more proper one(800x600 preobably). Thank you :)