On Friday 14 March 2008, Dr. Alexander K. Seewald wrote: > Still image capture support would be cool. If anyone needs my help, > just ask. This could probably improve the handling of multiple > cameras, as we could leave all connections open and request images > as needed... which is not possible with the current USB-bandwidth- > hungry video streaming protocol.
Still image capture wouldn't help much. Most devices don't have a separate endpoint to transfer still images but implement still image capture using method 1 defined in the UVC spec as "Method 1 - The host software will extract the next available video frame from the active video pipe in the relevant VideoStreaming interface upon receiving the hardware trigger event. The hardware does not interrupt or alter the video stream in this case. For this method, the still image frame is always the same size as the video frames being streamed." This make still image capture a software-only process and requires an active video stream to work. Method 1 could be easily implemented if we had a proper still image transfer API in V4L2, but in the end it wouldn't help much. Forwarding the button press event to userspace would in my opinion be more useful. Best regards, Laurent Pinchart _______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
