Searching ACTIVE-X for video capture with time-Shift

[tomk3]

Hello to all,

i am looking for an active-x / dll if possible to be used in vfp without ".Net connector" which can capture video from USB and IP-cams and can do timeshift rewind and playback while continue capture, no audio necessary)

It seems to be that the viscom products do not have timeshift, I thought of VLC active-x , but did not find samples with timeshift?
I also found avicap, mediacapture, media foundation from MS but to start seems to be very, very hard.


I would be glad if you have recommendations for me (commercial one ok)

Thanks a lot in advance
Tom

 

[Chriss Miller]

Timeshift has multiple meanings, could you clarify what feature you need.

Timeshift sometimes is referred to prerecording up to a maximum length so when you press record you can choose the recording to begin up to that buffered length earlier, i.e. you can wait for something to happen and then react but still have a few seconds up to maybe an hour before, too. Another reference is that you can watch already while the recording still runs, a typical feature of DVR. Both features rely on the same: Buffering of a video stream you can read while it's written. Still, only one or the other feature might be supported and called timeshift and you might need the other. Or even both, perhaps?

What's it for? Security cam? Production process monitoring?

Do you need to support existing cameras or is this the starting point and you not only look for the OCX software part of it, but an overall solution? Then I'd llook into what's offered in hardware including features of the camera itself and bundled software. I guess that's the aspect where more customized software is asked for, but the basis could be more than just the bare capability to record with one or the other timeshift feature.

A quick google search gave me AI assisted industry cameras, for example. Quite sure they don't come with an OCX for own custom software development, but you never know what API about the video recording is supported or what you can control and automate otherwise.

 

[Chriss Miller]

Just a thought about how you can offer timeshift, even if a video recording OCX or DLL only allows recording or playback, not both at the same time: You record in short chunks, maybe only 1s each and then work with these, the only downside is that you have to wait 1s for being able to access that last second, but you can still offer any timeshift, not just full seconds. I almost had a job like this, but that was so long ago, that I don't even remember what cameras and software we tested, that company doesn't even exist anymore.

 

[tomk3]

Hello Chris,

thanks for your answer, taking chunks is an option.
Its a security solution and we must supply existing cams (USB / IP) and we have to have access to the video to show and react on it in our programs (take snapshots with defined names,...)

Timeshift should be "buffering" , so make it possible to rewind and playback while capture continues. VLC offers this, but I did not ind an activex to do that.

 

[Chriss Miller]

we must supply existing cams (USB / IP) and we have to have access to the video

What comes with the cams?

The basis APIs for Windows changed from Twain (pre Windows Me) over Wia (Me to XP), then became DirectShow (Vista-Windows 8) and Microsoft Media Foundation (in short MMF - also staring with Visa). That's as far as a little research regarding Windows offerings brought up for me.

Especially https://learn.microsoft.com/en-us/windows/win32/directshow/directshow

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11.

That won't help directly, the major thing to find out is how the cams you need to support can be addressed. It won't only depend on which Windows Version you're using, but also whether the cams even embed themselves with their drivers into Wia, DirectShow or Media Foundation.

I think if I dig up a bit I find WIA examples for VFP, so two generations back from the currently recommeded Windows layer for the topic.

If you don't need to control the cameras themselves but only handle the videos they record, that makes it mostly a topic of video formats and video playback.

I guess you can't have playback of what's currently recording, unless your software records the file and thus has full (exclusive) access to the video file/stream and that speaks for digging into MMF or DirectShow or WIA.

I have only these starting points and would need to dig in from there myself, too, though. Hopefully this information can help you find something like a library simplifying development of MMF based applications. Once you're sure the cams you need to support can be addressed by MMF. Otherwise you'll need a library for DirectShow or WIA, perhaps. Or something avoiding all these Windows interfaces and directly addressing the cameras. An IP camera might actually give you a sream on some defined URL, which would mean direct hands on that. The way to handle HTTP based things in VFP is limited with COM helper classes, though and/or wouldn't address the topic of handling a video stream in itself.