Run multiple webcams at a time using DirectShow

Question

I'm using Windows 7 OS. working with Visual Studio 2010. Here I'm usng DirectShow2005-Lib.dll. Here I'm able to run two webcams at a time. But when I'm going to connect and run the 3rd webcam .. I'm not able to run all the three at a time. I can run only two at a time. and getting an error : No combination of intermediate filters could be found to make the connection.

How can I run multiple webcams at a time using DirectShow?

score 5 · Accepted Answer · edited May 23 '17 at 10:28

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USB bandwidith is a limited resource and you cannot run too many cameras. Sometimes, in some modes, you can run only one camera at a time.

See:

edited May 23 '17 at 10:28

Community

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answered Aug 16 '12 at 11:49

Roman R.

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score 2 · Answer 2 · edited Sep 12 '12 at 12:55

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The problem is solved. I have used PCI Card USB Slot. Two cameras connected to the PCI USB slot and one to normal USB slot. Thus all the three cameras are running simultaneously at the same time.

We can also use USB Hub for this.

edited Sep 12 '12 at 12:55

ЯegDwight

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answered Sep 12 '12 at 12:20

DShahu

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So it was bandwidth. A hub probably wont help as it's all going back to the same root hub on the machien with the same limitation. – Deanna Sep 12 '12 at 15:42

score 0 · Answer 3 · answered Aug 16 '12 at 12:35

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Some (most?) drivers I've encountered don't allow multiple instances to be loaded. As you already have 2 loaded, this is unlikely to be the case, but this is for future reference.

answered Aug 16 '12 at 12:35

Deanna

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score 0 · Answer 4 · answered Aug 30 '12 at 13:18

I’ve noticed 2 instances when I receive the same error:

1)I’m trying to connect to a web cam that is already running a graph. (most webcam drivers can only have one instance open, like Deana mentioned)

2)You’re connecting to the wrong pins or you need to set up a smart T filter for that particular camera.

Are you using the same cameras (if so be cautious of not running the same one twice)? USB bandwidth won’t be an issue if your pumping out low resolution, but if your frames are over 3MP you could run into issues only if you’re running off the same USB port…
Step through the graph, where exactly is it failing?

Thank you for all of the replies. (Specially to Roman R.) The problem is solved. I have used PCI Card USB Slot. Two cameras connected to the PCI USB slot and one to normal USB slot. Thus all the three cameras are running simultaneously at the same time. We can also use USB Hub for this. Thanks again ! :) — DShahu, Sep 12 '12 at 12:16

Run multiple webcams at a time using DirectShow

4 Answers4