Changes between Version 6 and Version 7 of linux/media


Ignore:
Timestamp:
02/20/2019 10:25:06 PM (4 years ago)
Author:
Tim Harvey
Comment:

added EDID section

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  • linux/media

    v6 v7  
    447447     rtph264pay ! udpsink host=$SERVER port=$PORT
    448448}}}
     449
     450
     451
     452[=#edid]
     453== EDID
     454HDMI sources require an EDID from the HDMI sink (ie monitor/capture device) to know what formats are allowed. This is done on v4l2 capture devices such as the tda1997x by using the 'v4l2-ctl --set-edid' on the subdev for the capture device. The capture device will then provide this to the HDMI source (it wiggles its HPD line which is the equivalent of a hotplug) and then the HDMI source will provide the sink (capture device) with something compatible which you can then query. You can provide either a raw EDID binary file or a type which will cause the kernel to auto-generate a compatible EDID from.
     455
     456Examples:
     457 - show options for setting edid:
     458{{{#!bash
     459v4l2-ctl --help-edid
     460}}}
     461 - provide an EDID to the tda1997x by description:
     462{{{#!bash
     463v4l2-ctl -d $(media-ctl -e "tda19971 2-0048") --set-edid=type=hdmi
     464}}}
     465 - provide an EDID by binary file
     466{{{#!bash
     467v4l2-ctl -d $(media-ctl -e "tda19971 2-0048") --set-edid=file=edid.hex # hex
     468v4l2-ctl -d $(media-ctl -e "tda19971 2-0048") --set-edid=file=edid.bin,format=raw # binary
     469}}}
     470 - clear the EDID:
     471{{{#!bash
     472v4l2-ctl -d $(media-ctl -e "tda19971 2-0048") --clear-edid
     473}}}
     474 - get edid
     475{{{#!bash
     476# show it in hex format
     477v4l2-ctl -d $(media-ctl -e "tda19971 2-0048") --get-edid=format=hex
     478# save it to a file
     479v4l2-ctl -d $(media-ctl -e "tda19971 2-0048") --get-edid pad=0,file=edid.hex,format=hex # hex
     480v4l2-ctl -d $(media-ctl -e "tda19971 2-0048") --get-edid file=edid.bin,format=raw # binary
     481}}}
     482
     483Notes:
     484 - the above commands do not provide the optional 'pad' argument as it defaults to pad 0 which is the only pad of the tda1997x