Hello all,
I'm currently starting to work with v4l. I'm not sure if this is the right place to post this question, but as this group has relation with v4l, I'll try also here. The question is about digital zoom capabilities. I'm a little confused about how to implement crop related ioctls in a v4l2 driver. First of all, what is the common application flow to probe zoom capabilities from a v4l2 driver? What is the common application flow to get and set current zoom settings from a v4l2 driver? AFAIU, applications must combine VIDIOC_CROPCAP, VIDIOC_[S,G]_CROP with VIDIOC_[S,G]_FMT. What application is a good example for this issue? Suppose a device which supports following modes: - mode 1 (640, 480), - mode 2 (320, 240) from window (0,0) to (640, 480) and - mode 3 (320, 240) from window (161, 121) to (480, 360) What is the best way to implement this support? I can see at least one option here: export the bounds and defrect for cropcap as 640x480. When applications request formats, return to them what best fits between 640x480 or 320x240. And then, when applications request crop window modification, the behaviour would be, if they request a crop window equal to defrect, the device is changed to mode 1 or 2 (depending on the current format). however if the crop window requested is smaller then defrect, the mode 3 is configured. Is this behaviour expected or I misunderstood something? Cheers, -- Eduardo Bezerra Valentin _______________________________________________ Linux-uvc-devel mailing list Linux-uvc-devel@lists.berlios.de https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
