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I am working on a project that involves a raspberry pi outputting video to tvs. I'd like to have the raspberry pi always output FullHD video.

If it was booted without a display, by default it switched to composite. By adding force_hdmi_hotplug=1 or something along those lines I got it to always output on HDMI.

However if I power it on without a display, it defaults to a lower resolution (720p?). I could force a specific CEA/DMT mode, but the displays have different refresh rates and progressive/interlaced modes, so I would have to find a mode supported by all.

How would I solve this?

I guess I would have to either:

  • configure it to keep the resolution and find the best mode when a tv is plugged
  • manually poll available modes, try to find the best, and tell to switch to that. How would I change resolution on command line? I have the X server running a single app without a window manager / desktop environment
  • AFAIK, Raspberry Pi always uses 720p mode, but upscales it to the 1080p if necessary. – lenik May 14 '14 at 16:11
  • @lenik, Interesting, I didn't know that. Is there a way to force upscale then? :) – varesa May 14 '14 at 17:16
  • rPi does full 1080p, not just upscaled. – me-- May 14 '14 at 23:34
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In the /boot/config.txt file you could try to adjust the framebuffer_width and framebuffer_height settings to 1920x1080, this will force the image at that resolution through the HDMI port.

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