View Full Version : Event Not Trigger

August 3, 2004, 05:35:05
When I used your component to record a video, the imageavailable event is not triggered, may I know is there any way which I can get a sequential still images from the live capture source when capturing video? Thanks.

Johannes Vogel
August 3, 2004, 09:42:44

Are you using the .NET component or the ActiveX ?

Which programming language are you using?

August 3, 2004, 10:32:16
I'm using ActiveX control in VB6.

Johannes Vogel
August 3, 2004, 13:16:58

If you want to capture a series of images, you should use the built-in ring buffer and the "ImageAvailable" evetn. Please refer to the VB sample "Displaying Buffers in the ImageAvailable Event" for details.

During AVI recording, the ImageAvailable ecent will not be fired.

August 3, 2004, 15:13:55
Is there any way to get still image during AVI recording?

Is the latest version 2 or .net able to do that?

Johannes Vogel
August 3, 2004, 15:31:41

The latest version is 2.0. The .NET component provides the same functionality as the ActiveX.

Currently, there is no way to get image buffers while writing to an AVI file. If you want to do this, you will have to get all frames out of the ring buffer in the ImageAvailable event and write them yourself to an AVI file using the DirectShow API directly.

August 4, 2004, 02:04:40
I already did it that way, pull out all frames at ImageAvailable event and save to avi file, but only get 6-8 frames per sec in the recording file. If I set it to 25/30 fps then the video look like fast forward.
Furthermore when using this method, the cpu reach 100% while there are 2 video capture devices activated.

Any advice? Thanks.

Johannes Vogel
August 4, 2004, 09:34:57

Your setup requires the highest possible processor speed. The following factors influence the possible fps and have to be balanced.:

1) video format: size and pixel format
2) codec and quality level
3) system performance (peocessor, speed, memory, disk system).

BTW, why do you need to have access to the image data if you want to store all frames in the AVI file ?

August 4, 2004, 10:01:10
why do you need to have access to the image data if you want to store all frames in the AVI file ?

Because I need to save still images (JPG) and avi video at the same time. If not, what is your suggestion?

Johannes Vogel
August 4, 2004, 13:29:30

ok, in this case, the only way is the one you are doing it now. Maybe you can extract single frames out of the AVI after recording. If that works out ok qualitywise, you will gain performance for the AVI recording.