Re: VGA–USB adapter, Ubuntu 12.04?

[Johnny Rosenberg]

2013/2/23 Johnny Rosenberg <gurus.knugum at gmail.com>:
> 2013/2/23 Colin Law <clanlaw at googlemail.com>:
>> On 23 February 2013 14:28, Johnny Rosenberg <gurus.knugum at gmail.com> wrote:
>>> 2013/2/23 Colin Law <clanlaw at googlemail.com>:
>>>> On 23 February 2013 13:41, Johnny Rosenberg <gurus.knugum at gmail.com> wrote:
>>>>> Have searched a bit but so far I only saw the opposite of what I want.
>>>>>
>>>>> I have a device with a VGA output, and what I want to do is to take
>>>>> screenshots from it, so I need to bring its video signal to Ubuntu
>>>>> somehow, making it appear in a window that I can take a screenshot
>>>>> from.
>>>>
>>>> You need a video capture device.  Google for
>>>> video capture vga
>>>> and you will find them.  Does it have a Composite Video output (yellow
>>>> phono socket, at least I think the video is the yellow one)?
>>>
>>> It only has a VGA output, nothing else (except a lot of ins and outs
>>> for other things than video signals):
>>
>> If the VGA has TV-Out signals (you would have to check the spec to
>> find out) then you could use something like
>> http://www.ebay.co.uk/itm/1-5M-VGA-to-3-RCA-COMPOSITE-VIDEO-CABLE-PC-TV-LAPTOP-/151000907450?pt=UK_Computing_CablesConnectors_RL&hash=item23285afeba
>> to convert to composite video then one of the cheap video capture
>> devices  to capture it.
>
> Checked all my manuals, but it was not mentioned. I think it's just
> VGA (640×480, 256 colours) and nothing else. The manuals only talk
> about connecting it to VGA monitors, nothing about TV signals
> mentioned anywhere. It is a 24 channel audio recording device (from
> 2001…) so I don't think they spent too much time designing the VGA
> output… There is a built in display (320×240, 2 colours), and the unit
> is designed to use it, rather than an external monitor. The VGA output
> was originally just a nice bonus… (before they upgraded the internal
> software to 2.0, the external monitor was for viewing only, you could
> still only work with the built in display. 2.0 meant that you could
> suddenly work directly on a VGA monitor).
>
>>
>>> Thanks for the searching hints.
>>
>> I hope you did not think I was suggesting that you should have googled
>> first, that was not my intention.  I am sure you did google but
>> without the right keywords was probably not successful.
>
> Yes, I wrote in my first post that I ”have searched a bit”, so I was
> just talking about your hints about what to search for.
>
>
>
> Johnny Rosenberg
>>
>> Cheers
>>
>> Colin
>>

I found more things now. One of them is the Epiphan VGA2USB:
http://www.epiphan.com/products/frame-grabbers/vga2usb/

They had a Pro version for $2000, but that's just a LITTLE too much for me… :P
The cheapest version is around $300. All versions are compatible with
V4L and there is even a tutorial for how to set it up in Linux.

Here's a comparison table:
http://www.epiphan.com/products/frame-grabbers/

It says, among other things, that the frame rate at 640×480 is 29 fps.
My source has a settable ”refresh rate”: 60, 66, 70 and 75 Hz.
Could this be a problem?
I know that refresh rate and frame rate is not the same thing, but
still… do I need to worry about that?
My main purpose is to capture still images anyway, but if recording
video, the target frame rate will be 25 fps.


Johnny Rosenberg