[libcamera-devel] [PATCH v2 00/27] GStreamer Element for libcamera

[Laurent Pinchart]

Hi Nicolas,

On Thu, Feb 27, 2020 at 03:03:40PM -0500, Nicolas Dufresne wrote:
> This patchset introduces two GStreamer features for libcamera. A
> GstDeviceProvider that allow enumerating the cameras and a libcamerasrc element
> the allow streaming from a selected camera.

Great work ! Thanks a lot again, it's very nice to see the gstreamer
element nearing completion.

> This is an early implementation that is not feature complete. It is designed to
> support multiple streams even though it currently only allow one srcpad. The goal
> of this submission is to get an inital element merged so that further
> improvement can happen incrementally.
> 
> To test these features, you'll need GStreamer 1.16 (downgrade might be

Is this still true ?

> possible). To get the list of cameras you can run the following. Regression
> exist in the monitor of GStreamer 1.16.2 that may cause a crash, and also in
> master that may show nothing. This will be addressed in later release of
> GStreamer.
> 
>   gst-device-monitor-1.0 Video/Source
> 
> To stream from a cameram, you can use the following pipeline:
> 
>   gst-launch-1.0 libcamerasrc ! videoconvert ! autovideosink

Would you be able to add this to a README.md in the gstreamer directory
? Maybe with just a bit of additional information to tell how to select
a camera ? And with any additional design documentation that you think
would be useful for the future (for instance briefly explaining the
rationale behind some of the design decisions) to help other developers
?

> Changes since v1:
>   - Fixed review comments
>   - Use a C++ class for glib mutex scoped locker
>   - Fixed a potential deadlock on exhausted buffer pool
>   - Minimum GStreamer requirement now set to 1.14
> 
> Jakub Adam (2):
>   gst: utils: Factor-out the task resume helper
>   gst: libcamerasrc: Prevent src task deadlock on exhausted buffer pool
> 
> Nicolas Dufresne (25):
>   Add GStreamer plugin and element skeleton
>   gst: Add utility to convert StreamFormats to GstCaps
>   gst: Add initial device provider
>   gst: utils: Add simple scoped lockers for GMutex and GRectMutex
>   gst: Add pads to the source
>   gst: libcamerasrc: Allocate and add static pad
>   gst: libcamerasrc: Add camera-name property
>   gst: libcamerasrc: Add a debug category
>   gst: libcamerasrc: Implement selection and acquisition
>   gst: libcamerasrc: Add a task for the streaming thread
>   gst: libcamerapad: Add a method to access the role
>   gst: libcamerasrc: Store the srcpad in a vector
>   gst: libcamerasrc: Send stream start event
>   gst: utils: Add StreamConfiguration helpers
>   gst: libcamerasrc: Implement minimal caps negotiation
>   gst: libcamerasrc: Push segment event
>   gst: Add a pool and an allocator implementation
>   gst: libcamerapad: Allow storing a pool
>   gst: libcamerasrc: Allocate and release buffers
>   gst: Add getters for Stream and FrameBuffer
>   gst: pad: Add method to store retrieve pending buffers
>   gst: libcamerasrc: Implement initial streaming
>   gst: libcamerasrc: Implement timestamp support
>   gst: libcamerasrc: Add a TODO comment
>   gst: Reduce GStreamer requirement to 1.14
> 
>  meson_options.txt                       |   5 +
>  src/gstreamer/gstlibcamera-utils.cpp    | 173 +++++++
>  src/gstreamer/gstlibcamera-utils.h      |  73 +++
>  src/gstreamer/gstlibcamera.c            |  27 +
>  src/gstreamer/gstlibcameraallocator.cpp | 252 +++++++++
>  src/gstreamer/gstlibcameraallocator.h   |  31 ++
>  src/gstreamer/gstlibcamerapad.cpp       | 197 +++++++
>  src/gstreamer/gstlibcamerapad.h         |  37 ++
>  src/gstreamer/gstlibcamerapool.cpp      | 145 ++++++
>  src/gstreamer/gstlibcamerapool.h        |  39 ++
>  src/gstreamer/gstlibcameraprovider.cpp  | 235 +++++++++
>  src/gstreamer/gstlibcameraprovider.h    |  23 +
>  src/gstreamer/gstlibcamerasrc.cpp       | 654 ++++++++++++++++++++++++
>  src/gstreamer/gstlibcamerasrc.h         |  22 +
>  src/gstreamer/meson.build               |  30 ++
>  src/meson.build                         |   2 +
>  16 files changed, 1945 insertions(+)
>  create mode 100644 src/gstreamer/gstlibcamera-utils.cpp
>  create mode 100644 src/gstreamer/gstlibcamera-utils.h
>  create mode 100644 src/gstreamer/gstlibcamera.c
>  create mode 100644 src/gstreamer/gstlibcameraallocator.cpp
>  create mode 100644 src/gstreamer/gstlibcameraallocator.h
>  create mode 100644 src/gstreamer/gstlibcamerapad.cpp
>  create mode 100644 src/gstreamer/gstlibcamerapad.h
>  create mode 100644 src/gstreamer/gstlibcamerapool.cpp
>  create mode 100644 src/gstreamer/gstlibcamerapool.h
>  create mode 100644 src/gstreamer/gstlibcameraprovider.cpp
>  create mode 100644 src/gstreamer/gstlibcameraprovider.h
>  create mode 100644 src/gstreamer/gstlibcamerasrc.cpp
>  create mode 100644 src/gstreamer/gstlibcamerasrc.h
>  create mode 100644 src/gstreamer/meson.build

-- 
Regards,

Laurent Pinchart