[libcamera-devel] [PATCH 0/1] Fake Pipeline Handler

[Kieran Bingham]

Quoting Cheng-Hao Yang (2022-10-12 10:42:32)
> Thanks Kieran for your thoughts!
> 
> On Wed, Oct 12, 2022 at 5:10 PM Kieran Bingham <
> kieran.bingham at ideasonboard.com> wrote:
> 
> > Quoting Harvey Yang via libcamera-devel (2022-10-12 08:59:24)
> > > This is a POC PATCH of the fake pipeline handler, which should be used
> > > for tests and validating Android adaptor can pass CTS limited mode.
> > >
> >
> > Aha, this is interesting. I've wondered if we should have a virtual/fake
> > camera too, perhaps with our own internal pattern generator.
> >
> >
> This fake pipeline handler actually came from a design in ChromeOS
> that tried to do some tests (CTS for example) without involving the real
> cameras, like green frames or providing frames from a prepared video file.
> 
> We also wonder how the fake pipeline handler could help libcamera scale
> and launch on more real devices.

Is there a reason you couldn't use the VIMC camera?
 (modprobe vimc is perhaps required)

Though I think I've already seen situations where it would be helpful to
have a fake camera that produces a test pattern, without requiring
kernel drivers...


> > There's lots that could be mocked up, perhaps even as far down as a Fake
> > CameraSensor, and an IPA to support testing of controls too (or perhaps
> > without an IPA as it could all be internal to the pipeline handler, with
> > no particular imagery).
> >
> >
> Yeah there's a TODO to read a prepared configuration file, which defines
> the
> fake cameras and maybe a prepared video file as well. True that I was not
> sure
> why an IPA is needed. Maybe some controls can be applied on the output
> frames
> (from the video)?

If there's an internal test pattern generator yes. But I don't think we
should introduce any kind of 'video' decoder.

> There's a lot of commented code in there from the IPU3, so I suspect
> > that was the source.
> >
> > There's https://git.libcamera.org/libcamera/vivid.git/log/ which might
> > be a 'smaller' pipeline handler to consider as a fake pipeline handler
> > starting point, or even UVC might be simpler comparable starting point.
> >
> >
> Thanks! Will take a look and update on my next patch.
> 
> 
> > --
> > Kieran
> >
> >
> >
> > > Signed-off-by: Harvey Yang <chenghaoyang at chromium.org>
> > >
> > > Harvey Yang (1):
> > >   Add fake pipeline handler
> > >
> > >  meson_options.txt                       |   2 +-
> > >  src/android/camera_capabilities.cpp     |   1 +
> > >  src/libcamera/pipeline/fake/fake.cpp    | 518 ++++++++++++++++++++++++
> > >  src/libcamera/pipeline/fake/meson.build |   3 +
> > >  src/libcamera/pipeline_handler.cpp      |   2 +-
> > >  test/camera/camera_reconfigure.cpp      |   2 +-
> > >  6 files changed, 525 insertions(+), 3 deletions(-)
> > >  create mode 100644 src/libcamera/pipeline/fake/fake.cpp
> > >  create mode 100644 src/libcamera/pipeline/fake/meson.build
> > >
> > > --
> > > 2.38.0.rc1.362.ged0d419d3c-goog
> > >
> >