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240p Composite video?

Posted: Sun Mar 15, 2015 9:21 pm
by JTCook
Is there any way to enable 240p composite video on the Raspberry Pi? I have been able to set the resolution to 320x240, but I believe it is 480i.

Re: 240p Composite video?

Posted: Sun Mar 15, 2015 9:34 pm
by mahjongg
Composite resolutions are NOT affected by how you set up HDMI output, they are always downscaled (or in rare cases upscaled) to the same invariable PAL or NTSC resolutions.

Re: 240p Composite video?

Posted: Mon Mar 16, 2015 2:47 am
by JTCook
Back to the question at hand...
is there a way to enable 240p for composite video?

Re: 240p Composite video?

Posted: Mon Mar 16, 2015 7:06 am
by fruitoftheloom
JTCook wrote:Back to the question at hand...
is there a way to enable 240p for composite video?
http://en.wikipedia.org/wiki/Composite_video

Composite video (one channel) is an analog video transmission (without audio) that carries standard definition video typically at 480i or 576i resolution.

Re: 240p Composite video?

Posted: Mon Mar 16, 2015 7:10 am
by rpdom
JTCook wrote:Back to the question at hand...
is there a way to enable 240p for composite video?
No.
Standard Composite video does not do 240p.

Re: 240p Composite video?

Posted: Mon Mar 16, 2015 10:04 am
by DougieLawson
JTCook wrote:Back to the question at hand...
is there a way to enable 240p for composite video?
You can set the framebuffer height and width in /boot/config.txt

Re: 240p Composite video?

Posted: Tue Mar 17, 2015 5:05 am
by JTCook
This is a common output method for older video game systems, and early computer systems. This mode does exist and was put to use 40 years ago. The Atari 2600, Commodore 64, NES, SNES, and as recently as the Nintendo Wii (among others).

http://en.wikipedia.org/wiki/Low-definition_television

I have also set the framebuffer to 320x240, but it upscales it to a 480i signal.

Re: 240p Composite video?

Posted: Tue Mar 17, 2015 5:12 am
by AndyD
JTCook wrote:This is a common output method for older video game systems, and early computer systems. This mode does exist and was put to use 40 years ago. The Atari 2600, Commodore 64, NES, SNES, and as recently as the Nintendo Wii (among others).

http://en.wikipedia.org/wiki/Low-definition_television

I have also set the framebuffer to 320x240, but it upscales it to a 480i signal.
The Raspberry Pi Documentation for config.txt list the following modes

Code: Select all

sdtv_mode 	result

0 	        Normal NTSC
1 	        Japanese version of NTSC – no pedestal
2 	        Normal PAL
3 	        Brazilian version of PAL – 525/60 rather than 625/50, different subcarrier
One of the current or ex Broadcom engineers is likely to be the only definitive source of information that can say if it is even possible for the Raspberry Pi to produce 240p composite. You could always raise an issue on the Raspberry Pi firmware if you think it should be supported.

Re: 240p Composite video?

Posted: Fri Nov 18, 2016 3:31 pm
by starquake