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Cheap HDMI capture for Linux

blog.benjojo.co.uk

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Re: Cheap HDMI capture for Linux

#21

Post by drothlis »

jamesfmilne wrote: post #7

You can also use devices that are USB Video Class (UVC) compliant, thus which don't require any drivers. libuvc can be used to capture from these devices: https://github.com/ktossell/libuvc You can get cheap off-brand UVC USB grabbers, or you can get higher quality gear, like the AJA U-TAP: https://www.aja.com/en/products/u-tap Admittedly though I haven't seen anything that comes close to £45 :-)

I second the UVC driver recommendation, or anything with drivers upstream (that is, in the Linux kernel itself). If this is for your day job spending £250 is well worth it for one of the better quality brands, otherwise you'll be spending far more than that debugging reliability issues.

Depending on your project, it might be worthwhile using GStreamer instead of tying yourself to a specific driver like libuvc. There's a lot you can do with just GStreamer's command-line tools -- for some examples see the first 5 minutes of my talk[1] -- and if you need more you can drop down into C or Python, though admittedly the learning curve is fairly high.

[1]: http://www.youtube.com/watch?v=Fdn2LxxM7wA&list=SPSIUOFhnxEi...

Re: Cheap HDMI capture for Linux

#23

Post by rasz_pl »

gm-conspiracy wrote: post #6

How would one go about compressing the captured stream? I read it can be containerized as an MKV, but then would you re-encode as H.264, or is there a better codec? I assume there is a quality vs time to encode trade-off? Also, would this be a component in a viable DIY HDMI matrix switch? I see this 4 input / 8 output 4K HDMI matrix switch for only $169 on Amazon here: http://amzn.to/28Ykyor So, cost-wise not viable,…

no need, just buy never version: https://blog.danman.eu/new-version-of-lenkeng-hdmi-over-ip-e...

Re: Cheap HDMI capture for Linux

#24

Post by VLM »

benjojo12 wrote: post #14
0942v8653 wrote: post #4

What 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

Hurray! Therefore this will be quite handy for mythtv, eventually. Will require some messing around to integrate it into the myth system.

Re: Cheap HDMI capture for Linux

#25

Post by Hytosys »

benjojo12 wrote: post #12
SoapSeller wrote: post #3

Cool 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.

I coded the Blackmagic support for OBS Studio. It was only slightly nightmarish.

https://github.com/jp9000/obs-studio/tree/master/plugins/dec...

Re: Cheap HDMI capture for Linux

#26

Post by jerf »

reycharles wrote: post #20
jrockway wrote: post #5

Earlier quoted context omitted.

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.

De jure it does not. De facto, well... at the point where you're selling gizmos on Amazon and nothing's happening to the sellers or the purchasers, it probably doesn't matter.

Re: Cheap HDMI capture for Linux

#27

Post by [deleted] »

drothlis wrote: post #21
jamesfmilne wrote: post #7

You can also use devices that are USB Video Class (UVC) compliant, thus which don't require any drivers. libuvc can be used to capture from these devices: https://github.com/ktossell/libuvc You can get cheap off-brand UVC USB grabbers, or you can get higher quality gear, like the AJA U-TAP: https://www.aja.com/en/products/u-tap Admittedly though I haven't seen anything that comes close to £45 :-)

I second the UVC driver recommendation, or anything with drivers upstream (that is, in the Linux kernel itself). If this is for your day job spending £250 is well worth it for one of the better quality brands, otherwise you'll be spending far more than that debugging reliability issues. Depending on your project, it might be worthwhile using GStreamer instead of tying yourself to a specific driver like libuvc. There'…

[deleted]

Re: Cheap HDMI capture for Linux

#28

Post by legooolas »

VLM wrote: post #24
benjojo12 wrote: post #14

Earlier quoted context omitted.

This device happily decodes HDCP. I figured the manufacturer does not care

Hurray! Therefore this will be quite handy for mythtv, eventually. Will require some messing around to integrate it into the myth system.

That is awesome, and would be something I would try and do right now, if I hadn't got rid of my cable subscription in favour of over-the-air Freeview (I'm in the UK).

Re: Cheap HDMI capture for Linux

#29

Post by dharma1 »

I wish there was something that worked on Android for HDMI input. Would be great to be able to repurpose tablets as external/field monitors. Some UVC dongles work, but I haven't seen any low cost 1080p ones

Re: Cheap HDMI capture for Linux

#30

Post by z02d »

Off-Topic but somehow related: I was thinking about to use my iDevices as generic HDMI-Displays.

The afaik best app for doing this is Duet Display [1], if you want to use Mac/Win. But I want to use it for a Raspberry Pi for example. Duet display streams the display information to the own application via ethernet over lightning port.

HDMI itself is also some network protocol (dangerous superficial knowledge). Theoretically it should be possible to build a small device, which translates hdmi video/audio to the same kind of network via lightning port as duet and display?

What do you think? Do you see any pitfalls there, which I don't see?

[1] http://www.duetdisplay.com/

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