View Full Version : Stability when faced with poor signal

June 24, 2005, 21:42:02
I'm using the DFG/1394-1 to capture frames from an antenna creating a composite signal. I have two difficulties I would like some help with:
1) I'm using a Grabber with an eGRAB FrameGrabberSink filling a two-frame MemBufferCollection and notifying a GrabberListener on eFRAMEREADY. If I don't have an active video signal when I start capturing, after a few seconds I get a blue screen that says: "INTERNAL ERROR" and then lists the video settings I initialized. That frame continues to be sent even after I connect a good video signal. Is there a way to detect when a good video connection has been established? How do I go about re-initializing the grabber so it will capture the signal?
2) My program works fine when I run with a directly-connected video source, but when I use the antenna which creates a weak/flaky signal, I have had the program (and Windows XP) crash on me: blue screen of death. I need to be able to work with possibly poor-quality video. How can I prevent things from crashing?


Stefan Geissler
June 27, 2005, 10:44:02

1.) You may ckeck some of the pixels of incoming frames. If they have all the same blue color, then there is no live video available and the DFG/1394-1 gives you its blue error screen.

2.) The blue screen of death is strange. It would be a great help to us, if you could send us the driver version number and a minidump from the crash. The minidump can be found in the Windows\minidump directory.

Please send this through an email to support@imagingcontrol.com .

June 27, 2005, 18:39:25
I've sent the requested information. As for question #1, after detecting that the frame is bad and recognizing that there is an internal error, assuming that the error is because my video isn't connect yet, what is the best way to reset the device so it will start capturing frames again?
Should I poll with Grabber::getSignalDetected until it returns 'true' and then run Grabber::startLive again? Is there a better way?



Stefan Geissler
June 28, 2005, 08:35:43
Hello Joseph,

we got your mail. The programming team will have a look on it and mail to you the results.

To question #1
You should try the getSignalDetected() method. If the signal keeps staying bad, startLive() won't help.

In my experiences will the DFG/1394-1 deliver an image as soon as it was able to synchronize to the video signal. The blue image will go away then and you do not need to reset the DFG/1394-1.

June 28, 2005, 16:52:20
Originally posted by Stefan Geissler
In my experiences will the DFG/1394-1 deliver an image as soon as it was able to synchronize to the video signal. The blue image will go away then and you do not need to reset the DFG/1394-1.

Interesting. Mine doesn't do that. Once it has encountered an internal error, it continues to send the blue error screen even after a good video signal is connected. It's not my code either because the same thing happens when I capture using the IC Capture utility provided with the device:

I start the application (with the firewire device plugged in, but no camera plugged into the device).
The application first says, "The device is currently not sending any images" and, after a few seconds, displays the blue "internal error" screen.
If I then connect a valid video source, the screen continues to show the blue screen. The device tab, under the 'Device properties' dialog correctly shows that "Signal Detected" is true. I can connect and disconnect the video and watch the check-mark come and go; but the video window stays blue.
If I click on the drop-down menu to set 'video size and color format' and select any option, then the video appears and works just fine. The same thing happens if I click on the 'video norm' drop-down and re-select NTSC. It does not work, however, to re-select the input channel. I presume that's because the device allows you to change channels while in 'live' mode and so startLive() never gets called again for that option.


Stefan Geissler
June 29, 2005, 09:06:09

i think, the problem is, that the DFG/1394-1 is connected to an instable video source. We had only connected video sources like cameras, video recorders and DVD players to the DFG/1394-1. With this devices, you can be sure, that the DFG/1394-1 can synchronize to the video stream.
I think the video signal that comes through your antenna is too disturbed, so the DFG/1394-1 can not recover and must be restarted.

June 29, 2005, 16:25:30
I don't think that's it. The above described behavior is from when I test in the lab using a regular video camera connected directly to the Comp1 port of the DFG/1394-1.


Stefan Geissler
June 29, 2005, 17:03:03

You may exchange the DFG/1394-1 if it is not too old.

September 28, 2006, 09:58:05

I am having the same problem described in this thread. The error message:
RGB24 640X480"
displayed in a blue window.

What was the final resolution to the problem?

Was the DFG-1394 returned for a replacement?

Was the problem resolved by the replacement DFG-1394?



Stefan Geissler
September 28, 2006, 14:12:17

Some computer also have trouble by transfering image data from the FireWire board into memory. This may occurs due to a concurrency situation on the PCI bus while Bluetooth, USB 2.0 or WLAN devices also want to communicate. In this case, the FireWire board is block. It has no own memory, thus it can not transfer packages into memory. These packages are overwritten by the next incoming packges and thus they are lost. This leads into incomplete images. If the images are too incomplete, then the DFG/1394-1e can display its "INTERNAL ERROR".

If it is only a video signal problem, then you may try to check the "VCR Input" property in IC Capture. May be the problem is solved then.