[Interest] Camera support for QtWebEngine

[Daniel Mack]

Hi,

In the meantime, I've updated to Qt 5.9.1, but that alone didn't fix the
issue yet.

To recap, the system I'm working with is a Qualcomm APQ8016 (Snapdragon
410), and I'm running an image built with Yocto. The goal is to have
QtWebEngine expose the camera in the system so that they become
available though regular HTML5 media objects. The camera works with the
QtMultimedia example code, so I hoped that QtWebEngine would just work.

I dug a little deeper now, and it turns out that the code that currently
handles the cameras is located in
src/3rdparty/chromium/media/capture/video/linux/v4l2_capture_delegate.cc,
and the code there chokes on the fact that the cameras are exposed with
V4L2_CAP_VIDEO_CAPTURE_MPLANE instead of V4L2_CAP_VIDEO_CAPTURE
capabilities, and V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE as buffer type.

There's also code in src/3rdparty/chromium/media/gpu/ which seems to be
prepared for type of devices, but according to the build system, it can
only be built for chromeos, not plain Linux.

I was under the impression that QtWebKit would just piggy-back on
QtMultiMedia for such things. Is that how things are supposed to work?
If so, what build-time configuration must be made to make this happen?


Thanks,
Daniel


On 05/24/2017 07:53 PM, Daniel Mack wrote:
> Hi,
> 
> I'm running QtWebKit 5.8 on Linux on aarch64 - the binaries are built
> with Yocto/OpenEmbedded, using the meta-qt5 layer.
> 
> Out-of-the-box, access to V4L2 camera devices isn't supported, and I
> wonder where to start looking. The same application works fine on
> x86-64, so it's really a platform-specific issue.
> 
> Are there any configuration parameters I need to be aware of when
> cross-compiling the sources? Does QtWebkit use QtMultimedia for such
> purposes by default? Because running a simple QCamera based application
> reports "Camera error "The camera service is missing" via the
> QCamera::Error signal. I'm not very familiar with the internals of Qt,
> so I can't make sense of that.
> 
> 
> 
> Thanks for any pointer,
> Daniel
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