On Mon, 2002-04-29 at 09:32, bong siu wrote: > Sometimes I saw some USB spec. saying "THis USB cam > can send 30 frames/ sec to the host." What kind of > video format are these frames? Are they Raw data or > jpeg format?
Usually YCrCb, sometimes RGB, sometimes jpeg (IIRC), and frequently cameras use proprietary compression schemes. Normally, cameras use broken or customized flavors of these formats to minimize the cost of the hardware. In some cases, the camera just sends raw sensor data, not even bothering with demosaicing (needless to say, this is very inefficient). > The other question is I am currently developing a USB > Cam. In order to increase the through-put, we are > trying to add a Mpeg encoder to the USB cam, so the > USB bus will only need to transfer Mpeg data. Do you > guys think that is a good idea? You would need a very fast CPU in the camera, or a dedicated encoder. Not only that; someone on the host side must decompress the MPEG stream to do something with the image - this will require some CPU as well. Maybe you would be better off using USB 2.0? Dmitri
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