[External] Re: About KVM screenshot

[Lei Yu]

On Mon, Sep 13, 2021 at 9:57 PM Paul Fertser <fercerpav at gmail.com> wrote:
>
> Hello,
>
> On Mon, Sep 13, 2021 at 09:47:03PM +0800, Lei Yu wrote:
> > The whole KVM screenshot is implemented by the below pieces:
> > 1. The vncsnapshot[1] is slightly modified for cross-compile, and a
> > bitbake recipe is created for it;
> > 2. A service is created to host the DBus interface to provide the
> > "Trigger" and "Clear" methods for KVM screenshot;
> > 3. OEM redfish actions are implemented to trigger and clear the KVM
> > screenshot, including the download of the picture;
>
> Currently obmc-ikvm gets a steady stream of JPG images, frame by
> frame, from V4L2. Have you considered extending it a bit so that it
> would be capable of simply saving the current frame to disk, without
> any conversion/transformation, just dump an array of bytes to a file?
>
> What would be the advantage of establishing a local VNC session with
> this additional software compared to the straightforward JPG to file
> writing?

Extending obmc-ikvm was my first thought, and when it's discussed in
Discord, @zevweiss mentioned that we could use the existing
vncsnapshot tool instead of writing new code.
And we tried and it worked fine with the limitation mentioned above.

With the obmc-ikvm extension to capture the JPG image, it has to deal
with two cases:
* When there is already a VNC session, it could just save the current
image when a snapshot is requested;
* When there is no VNC session, it has to open the video device and
capture the image.

We think vncsnapshot is much simpler to use in such case.

But I agree that it will be more efficient if we could implement the
feature in obmc-ikvm.

-- 
BRs,
Lei YU