Collecting pieces around something I call “green window project”.

Moving into a very small flat in Tokyo, with no good view outside? Ideas of using computer screens to replace windows are coming up. Most interesting is to collect content: waterfalls, nature and so on, free content. Kickstarter projects are also around: https://www.kickstarter.com/projects/atmoph/atmoph-window-your-room-can-be-anywhere .

Should a monitor or TV be used?

• 24“ and smaller, TV and monitor are equally expensive, but only TVs are available at bigger sizes
• Are 1920×1080 pixel enough? Using 4k will bring in the issue of having to supply the resolution.
• 4k nonitors are worse with contrast apparently
• monitors also have USB-hub usually
• C'T 11/2015 has optimized settings for TV: Samsung UE40HU6900S

Many settings of a TV are not appropriate here. Example: Samsung UE40HU6900S

• Βy default, the picture is cropped on all 4 edges. This can be fixed in the menu: picture/picture format/picture format: adapt
• picture is optimized for TV by default, not monitor. To tune (german):
  • Einstellungen / Bild / Hintergrundbel.: 6, Kontrast 90, Helligkeit 45, Schärfe 0
  • Bildformat: Bildanpassung
  • Erweiterte Einstellungen: Optimalkontrast: aus, Nur RGB-Modus: aus
  • Bildoptionen: Farbton: Warm2, Digital aufbereiten: aus, MPEG-Rauschfilter: aus, HDMI-Schwarzpegel: gering, Motion Plus: aus

The bigger the better, but..

• higher resolutions are also harder to supply with compute devices
• higher resolution content for the “greenwindow” is rarer
• intel Haswell desktop cpus for desktops can supply UHD-resolution 3840×2160 with 6hz via DisplayPort (mobile cpus support this only since Broadwell - but not Celeron/Pentium, here only 1920×1200 and 2560×1600 are allowed via DisplayPort)
• maybe the TV/monitor can independently display the content when i.e. supplied via USB/nfs- or samba share.

Bringing audio, video or pictures to the TV/monitor

• TV/monitor The device itself is able to show a picture show or the desired videos.
  • one can supply media on a usb stick or usb harddisk.
  • A DLNA server on a linuxbox can export directories with media files, the TV can then display it. Works also for 4k material - but a busy wlan does not provide the required bandwidth. This is what I use mostly. Simple. “dnf install -y minidlna; vi /etc/minidlna.conf; systemctl start minidlna”
• arm raspberry pie 2 is reported to to 4k with 15fps according to this, additional hardware used? The kickstart project uses an intel core cpu.
• x86 I have an unused thinkpad around. It has displayport output, but no usable audio. Do USB graphiccards for 2560x and higher resolutions exist?
• HDMI1.4 can do 4k resolutions with 30hz, 1920×1080 with 60Hz
• HDMI2.0
  • can do 4k resolutions with 60hz (some monitors with HDMI2.0 just entered the market)
  • only a few highend graphiccards support output to HDMI2.0
• Displayport1.1 does 4k resolutions with 30hz, the thinkpad x230 has an Intel(R) HD Graphics 4000 which only supports Displayport1.1a
• Displayport1.2 does 4k resolutions with 60hz, most 4k monitors are capable of this mode
• Displayport1.3 and Embedded Displayport 1.4a support 5k and 8k resolutions, but as of now no hardware supports it
• DVI can only transport 2560×1440 with 60Hz to the monitor

The content should be free.

• pictures:
  • A script, searching google image search for “nature” and displaying the results?
  • Script displaying random pictures from the harddisk, that have high resolution?
  • script displaying flicker pictures, i.e. from Hidehiko Sakashita / https://www.flickr.com/photos/hidesax/
• video: youtube, playing waterfalls or tree scenes? Is there better free content?
  • fetching from youtube:
    • “dnf install ffmpeg youtube-dl”
    • lookup video from https://youtube.com , set filter for 4k. Example: Jetman Dubai pipedream
    • Use “youtube-dl -F <url>” to see available formats, then i.e. “youtube-dl -f 266+140 https://www.youtube.com/watch?v=s0MDY9fl-IA” to fetch both audio+video and have them merged with ffmpeg.
• audio: a media player
• weather: seeing videolike what the weather is

Many computers like the thinkpad x230 here still have displayport 1.1a or other output which does not provide 4k resolution.

• Miracast is the right protocol for mirroring a device to the TV. Yet, Linux as source is almost unusable. Was only reported to have worked on one wlan model.
  • miraclecast seems active, https://github.com/albfan/miraclecast . But the wlan chip has to support certain functionality.
• minidlna can offer video files to be played. Yet, still no live streaming of a computer screen. The DLNA protocol might specify also streaming types.

• xrandr: I use xrandr directly to configure the screen connected to Linux: `xrandr –output HDMI1 –auto –below LVDS1`
• pulseaudio: The snd_hda_codec_hdmi module provides here the audio output. After turning the TV off, the audio output often appears as “unplugged”, even the TV is turned on again. Hacky workaround: `xrandr -s 0; xrandr –output HDMI1 –auto –below LVDS1`