Hi Ming, On 12/26/2011 03:00 AM, Ming Lei wrote: > On Thu, Dec 22, 2011 at 3:32 AM, Sylwester Nawrocki <snjw23@xxxxxxxxx> wrote: >>>> How is face detection enabled or disabled? >>> >>> Currently, streaming on will trigger detection enabling, and streaming >>> off will trigger detection disabling. >> >> We would need to develop a boolean control for this I think, this seems >> one of the basic features for the configuration interface. > > Yes, it is another way to do it, but considered that for the current two > use cases(detect objects on user space image or video, detect objects on > video stream from internal SoC bus), it is implicit that the video device > should have stream capability, so I think it is still OK to do it via > streaming on and streaming off interface. IMHO for drivers that support FD and don't expose an FD start control applications could assume that VIDIOC_STREAMON/VIDIOC_STREAMOFF also enables/disables face detection. In other words if an FD enable control is present face detection would be disabled until an FD start control is set. We will also need a FD status control. >>> Could you let me know how to do it? >> >> You would have to use multi-planar interface for that, which would >> introduce additional complexity at user interface. Moreover variable plane >> count is not supported in vb2. Relatively significant effort is required >> to add this IMHO. > > So the the introduced two IOCTLs are good to do it, right? Yes, and no :-) Since we have a third case to consider: 1) camera sensor with an embedded ISP that supports face detection. Another two are: 2) image input from memory only (like OMAP4 FDIF), 3) image input from memory OR from external image sensor. In case 1) we will eventually have a DMA that captures frames to memory. It's different from 2) and 3) that registers containing result are accessed through I2C. Then it may be desirable to retrieve detection result data separately for each object, due to bus access latencies, rather reading all data in single ioctl. > Sylwester, could you help to review the v2 patches if you are available? Yes, I'll try to find some time for it tomorrow. I would have a general note - I don't really think we should bother with generic FD kernel module now. We have already generic building blocks in V4L and hardware is so different that it's seems inappropriate to try to generalize the implementation before we have clear user interface semantics settled. -- Regards, Sylwester -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
