[FFmpeg-user] FFmpeg can't get access to webcam when excuted via Adobe AIR?

Roger Pack rogerdpack2 at gmail.com
Thu Sep 22 00:10:12 CEST 2011

> ffmpeg -f dshow -i video="Logitech QuickCam E2500":audio="Mikrofon (IDT High Definition A" -f flv rtmp://xyz
> As I said it works, when executed via the command line. But when I execute the same command from AIR I get the following error message in my AIR app:
> [dshow @ 01998640] Could not find video device.
> video="Logitech QuickCam E2500": Input/output error
> The question is: might this be a rights problem? Is it not allowed for FFmpeg to access my webcam when FFmpeg is executed via AIR? And if so, how can I solve it? Or is it some other problem?

Sounds like a rights problem.  Maybe you can specify in AIR
preferences which camera AIR has access to, or maybe...you can access
the raw bytes from the camera through AIR somehow?

> -          I cannot see a solution how to send the video of the webcam to a streaming server on Mac (dshow seems to work just for Windows). Is there no chance to have input via the webcam on Mac? Just Linux and Windows?

I have thought about that recently myself.  I don't think it can yet.
VLC has a qtcapture module, and once it gets working audio capture [1]
I hope to port it over to ffmpeg.

> -          What do you think about switching the cameras during runtime? Is that a problem? Will I stop the dshow-command by sending a "q" and start the next dshow-command with the different cam right after? How will this look like in the frontend? Black screen during the switch?

I believe so. Or rather one window disappears, the next appears.
Related: VLC has an --sout-keep option.  That...might maybe work.
Also I could hack you up a directshow video source device that
presents AviSynth (which has runtime scripts so it can change its
source...I think so anyway), but that would only be for windows so not


[1] http://forum.videolan.org/viewtopic.php?f=12&t=89140

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