# Question about how to start making a "simple" framegrabber

#### papajo

Joined Jun 21, 2015
12
Well I dont know if this is the right subtopic.. I would like to post this on the "pojects" one but guyz seem to discuss there already working projects or ones that are in progress...

I just had an idea and would like some (or a lot) help on resources i need to study, links, chip recommendations etc for that idea...

Well here it is: I have a compact camera with hdmi out, and I would like this camera to be used as a webcam (in other words i would like windows or programs like skype to see the device im thinking of as a video adapter/webcam ) lots of cameras have built in such capabilities but my doesnt, also I know there is softweare that can do this with some DSLRs/compact cameras with hdmi out but that software doesnt work with my camera (nikon coolpix s6600) And I know that there are some encoders that have hdmi in and usb out... like some avermedia products but I just choose to ignore them so that I can try to make this project happen

I didnt do much research on it (and I am not an electronics engineer etc... I am a mathematician and know lots of electronics theory... have done some basic arduino stuff and soldering and reballing, I also know some programming languages to an extent.. have basic logic gates knowledge etc but nothing more than that. )

And I havent done it because frankly i dont know were to start or how to built the corpus of my research in order just to learn the material I need for this project..

I dont aim to become an HDMI specialist or a programmer specialized in usb stacks/driver in general... I need to learn just the bids and parts of the theory relevant to make this project happen.

So according to my premature thought about that I need some sort of FPGA chip a usb 3.0 shield and a nand chip to act as a buffer for the data the FPGA chip and reading source for the usb shield in order to push the video signal to my pc as a webcame device (or whatever does the trick like video adapter device in order to work as a source for programs like skype)

To put it more simple I want to grab the HMDI out signal from my camera (that is already compatible for a tV to project it) and without encoding it or altering it (atleast if thats not mandatory for what I am trying to achieve) "push it through" usb in order for me to use that signal as a webcam feed for chating online with people using my camera instead of a webcam...

So were do i need to start with ?? also give me whatever advise,links hardware/devkit you think would be best suited for my venture

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#### Brownout

Joined Jan 10, 2012
2,390
You really have your work cut out for you. Why not just buy a webcam? I got a gently used on from Amazon for like 12 bucks, and I'm using it with free software as a security cam.

#### papajo

Joined Jun 21, 2015
12
I have already a webcam and actually the best there is... the c930e.. but its not about money its about making that project happen...
And its not just for the lolz compact cameras/camcoders/DSLRs have so much better quality,boke,field of view dynamic range etc than any webcam even if we compare compact cameras with the same price range as top webcams (100$ish) And I can use google to purchase something for my needs I already mentioned that... I would not make such a long post and in this forum if I wanted advice on buying a capturing device or webcam.. thank you for your time but your post doesnt help me. #### nsaspook Joined Aug 27, 2009 7,864 I have already a webcam and actually the best there is... the c930e.. but its not about money its about making that project happen... And its not just for the lolz compact cameras/camcoders/DSLRs have so much better quality,boke,field of view dynamic range etc than any webcam even if we compare compact cameras with the same price range as top webcams (100$ ish)

And I can use google to purchase something for my needs I already mentioned that... I would not make such a long post and in this forum if I wanted advice on buying a capturing device or webcam.. thank you for your time but your post doesnt help me.
You are asking about a very specialized skill on very specialized hardware on the order of what a 'Blackmagic' board can do. I don't think you have an idea of the scope of work that's needed to build something like that from scratch. The upfront design cost of something like that is very high.
https://www.blackmagicdesign.com/products/intensity

#### papajo

Joined Jun 21, 2015
12
You are asking about a very specialized skill on very specialized hardware on the order of what a 'Blackmagic' board can do. I don't think you have an idea of the scope of work that's needed to build something like that from scratch. The upfront design cost of something like that is very high.
https://www.blackmagicdesign.com/products/intensity
well yes except I dont want half of the stuff the black magic does I dont want to compress or decompress the input signal just grab it and feed it to the buffer nor do I want to do analog/digital conversion (and besides that I think this is cheaper and better http://gamerzone.avermedia.com/game_capture/live_gamer_extreme)

And yes I know what lies before me thats why I am asking for help on a forum with electronics experts .... I never said it would be a "plug this into that and paste that generic code" kind of deal.... and to be honest i dont know were you got that impression.

#### papajo

Joined Jun 21, 2015
12

#### kubeek

Joined Sep 20, 2005
5,736
As far as I know in HDMI the video can only be raw and uncompressed, only the audio can be compressed. It might be coming from a lower quality video inside the camera (repeating/interploated frames, upscaling...), but it is in rough terms "pixel for pixel" when it goes over the wire.

As for the encoding, you would have to choose some codec and have enough computing power to do it on the fly. There might be some specialized ASIC for that but it could be a bit hard to get to. Also, if I remember correctly a full-hd encoding is quite demanding and I don´t think that even a modern CPU (imagine I7 or similar) can reliably do it in real time.

#### papajo

Joined Jun 21, 2015
12
As far as I know in HDMI the video can only be raw and uncompressed, only the audio can be compressed. It might be coming from a lower quality video inside the camera (repeating/interploated frames, upscaling...), but it is in rough terms "pixel for pixel" when it goes over the wire.

As for the encoding, you would have to choose some codec and have enough computing power to do it on the fly. There might be some specialized ASIC for that but it could be a bit hard to get to. Also, if I remember correctly a full-hd encoding is quite demanding and I don´t think that even a modern CPU (imagine I7 or similar) can reliably do it in real time.
well if you are right then how does stuff like this work? [URL]http://gamerzone.avermedia.com/game_capture/live_gamer_extreme which feeds uncompressed 1080p@60fps from a source to the computer with only 50ms of delay (and it costs like 100\$ ) [/URL]

#### kubeek

Joined Sep 20, 2005
5,736
Looking at this video it seems that everything is done in the FPGA
Now I don´t think much of processing is happening in that fpga, but I may be wrong. Also, read the comments below.