The output image uses Rec. 709 R’G’B’ components, where the darkest value is 16 and the brightest is 235, which is why the colors look washed out. It would be fair to convert back to the original color space for the comparison.
Cheap HDMI capture for Linux
11–20 of 78 posts
Re: Cheap HDMI capture for Linux
#12Cool hack, but the part about the cost of off-the-shelf solutions is wildly wrong - Blackmagic's HDMI capture solutions can be purchased for less than 145usd for pci-e and 200usd for usb3 and they have free drivers&sdk for linux.
Could you link to examples of this? I am still looking for sane HDMI capture devices for the project that spawned this, I just could not find any decent proof that these drivers existed.
Re: Cheap HDMI capture for Linux
#13Cool hack, but the part about the cost of off-the-shelf solutions is wildly wrong - Blackmagic's HDMI capture solutions can be purchased for less than 145usd for pci-e and 200usd for usb3 and they have free drivers&sdk for linux.
Blackmagic's Linux drivers are gratis, but not libre. And of course they aren't
upstream. This means that they are only guaranteed to work if you use exactly
the same kernel that Blackmagic supports -- we've had all sorts of problems
with them: the cards lock up (requiring a reboot before they will work again);
the whole system locks up; the drivers were randomly overwriting other
processes' memory (!); etc.
However our reliability requirements may be different than yours & the OP's, as we (at http://stb-tester.com ) use video capture for automated UI testing so we need rock-solid reliability.
I concur with the other commenter that devices with an upstream driver --such as the UVC driver-- are the way to go.
Re: Cheap HDMI capture for Linux
#14What about HDMI DRM? Does it break it (illegal) or fail when it is used?
This device happily decodes HDCP. I figured the manufacturer does not care
Re: Cheap HDMI capture for Linux
#15Cool hack, but the part about the cost of off-the-shelf solutions is wildly wrong - Blackmagic's HDMI capture solutions can be purchased for less than 145usd for pci-e and 200usd for usb3 and they have free drivers&sdk for linux.
Could you link to examples of this? I am still looking for sane HDMI capture devices for the project that spawned this, I just could not find any decent proof that these drivers existed.
[deleted]
Re: Cheap HDMI capture for Linux
#16Earlier quoted context omitted.
Use any codec scheme you like. ffmpeg and mencode are the usual suspects, or Handbrake if you like GUIs to help you along. Realtime encoding is within the reach of some schemes on some processors.
Realtime encoding is within the reach of some schemes on some processors. Can you elaborate on that? What sort of setup (hw/sw) would one need to make this viable (realtime encoding from the stream)?
Intel GPUs + VAAPI (https://01.org/linuxgraphics/community/vaapi) can easily do H.264 encoding in real time.
P.S. See also https://trac.ffmpeg.org/wiki/HWAccelIntro
Re: Cheap HDMI capture for Linux
#17Are the gamer HDMI capture devices expensive because they have a low latency? (Besides the verticality of the market.)
Re: Cheap HDMI capture for Linux
#18A not cheap, but fully open source (hardware and firmware) solution also exists. https://github.com/timvideos/HDMI2USB
Re: Cheap HDMI capture for Linux
#19[deleted]
Re: Cheap HDMI capture for Linux
#20What about HDMI DRM? Does it break it (illegal) or fail when it is used?
Given the vast number of devices on Amazon that strip HDCP, and the fact that the master key was leaked many years ago, I doubt anyone that could act on this "illegal" activity cares anymore.
It's my understanding that the counter measures being completely broken (or not) doesn't matter.