View Full Version : Realtime sink video into AVI?

January 3, 2005, 23:18:53
My experience of using some video recording softwares tells me that usually a certain percent of frames will be dropped due to CPU load. Can I get a low drop rate using IC Imaging API when sinking video into an AVI file? Let's say the frame rate is 30Hz and the video format is 640x320.
Oh, I have another question. The sample start/end time generated from the IC driver is in unit second. If the video must be timestamped more precisely, I have to use Grabberlistener and write down the time in the frameReady function. Am I right?
Thank you very much

Johannes Vogel
January 4, 2005, 12:59:55

The number of dropped frames are dependent on several factors, such as: CPU type and speed, memory speed, codec and speed of the hard disk.

The sample time generated by the driver is in terms of 100ns.

January 4, 2005, 21:32:41
I tried to record video using IC Demo Application program. One question coming to me is why the saved AVI is of size 640x480 when the device is set to be 640x240? Frames are deinterlaced automatically? I don't expect it actually. How can I disable it?

Does the IC driver use high performance counter to get the sample time?

January 5, 2005, 10:57:17

Which device are you using?

Normally the selected VideoFormat for the device determines the dimensions of the avi file.

When you select a full format like 640x480 the video is deinterlaced by the device (or a decompressor filter) . When you select a half format like 640x240 the video should not be deinterlaced, but some devices interpret this wrongly and just deliver deinterlaced frames which have half the high.

In most cases the QueryPerformanceCounter is used to generate the time stamps (sample time), but this is device/directshow dependent and is not generated by IC.

Best regards

Christopher Koschack

January 5, 2005, 15:08:43
Thanks for your reply.
I use DFG/1394 converter. The interesting thing I just found is once I pick DV Video Encoder or Intel4:2:0 Video V2.50, the AVI video is always of size 720x480 whatever the device format is. But with Microsoft video 1 or Intel Indeo(R) Video R 3.2, the video has the same size as acquired.

Johannes Vogel
January 6, 2005, 10:06:57

Please try to open the property page of the DV codec. You should be able to set the output format there.