On Jun 18, 2007, at 7:21 AM, Chad Greenebaum wrote:
I’m writing an application to preview video from a camera and capture images when a button pressed. I’m working with a prototype camera that has the ability to send data to the Mac in 2 formats Component Video - CCIR-601 yuvu and MJPEG Open DML. Currently the camera captures images at Component Video - CCIR-601 yuvu however to get the full capabilities of the camera such as max resolution and frame rate I need to set the camera to use MJPEG Open DML. I’ve been using the Sequence Grabber to preview video and capture images however I cannot figure out how to configure the camera from the Sequence Grabber to transmit data in MJPEG Open DML. Everything I’ve tried has always resulted in the Sequence Grabber using the uncompressed CCIR-601 yuvu.
I tried SGSetVideoCompressor but could not find the MJPEG Open DML codec in GetCodecNameList. I tried SGSetVideoCompressorType which seemed to change the result when calling SGGetVideoCompressorType but didn’t change the actual camera function.
From ImageCompression.h:
kOpenDMLJPEGCodecType = 'dmb1',
This is the likely codec to use (I'm assuming this is a USBVDC camera). You'll probably need to SGSetChannelBounds to set your Rect to the correct frame size.
-Brad Ford
QuickTime Engineering
