[libcamera-devel] [PATCH v9 02/18] libcamera: property: Add MinimumRequests property
Jacopo Mondi
jacopo at jmondi.org
Fri Dec 16 15:00:59 CET 2022
Hi Paul
On Fri, Dec 16, 2022 at 09:29:23PM +0900, Paul Elder via libcamera-devel wrote:
> From: Nícolas F. R. A. Prado <nfraprado at collabora.com>
>
> The MinimumRequests property reports the minimum number of capture
> requests that the camera pipeline requires to have queued in order to
> sustain capture operations without frame drops. At this quantity,
> there's no guarantee that manual per-frame controls will apply
> correctly. The quantity needed for that may be added as a separate
> property in the future.
>
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado at collabora.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
>
Seems quite on-spot considering the thread Umang has just started
To be honest I would have expected this to generate more discussion,
but seeing Laurent's tag there makes me presume this has been blessed
already during the previous review.
> ---
> Changes in v9:
> - rebased
>
> Changes in v8:
> - Changed the MinimumRequests property meaning to require that frames aren't
> dropped
> - Set MinimumRequests on SimplePipeline depending on device and usage of
> converter
> - Undid definition of default MinimumRequests on CameraSensor constructor
> - Updated pipeline-handler guides with new MinimumRequests property
>
> Changes in v7:
> - Renamed property from MinNumRequests to MinimumRequests
> - Changed MinimumRequests property's description
>
> Changes in v6:
> - Removed comment from Raspberrypi MinNumRequests setting
> - Removed an extra blank line
> ---
> Documentation/guides/pipeline-handler.rst | 22 +++++++---
> src/libcamera/pipeline/ipu3/ipu3.cpp | 2 +
> .../pipeline/raspberrypi/raspberrypi.cpp | 2 +
> src/libcamera/pipeline/rkisp1/rkisp1.cpp | 2 +
> src/libcamera/pipeline/simple/simple.cpp | 40 +++++++++++++++++--
> src/libcamera/pipeline/uvcvideo/uvcvideo.cpp | 2 +
> src/libcamera/pipeline/vimc/vimc.cpp | 2 +
> src/libcamera/property_ids.yaml | 21 ++++++++++
> 8 files changed, 84 insertions(+), 9 deletions(-)
>
> diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst
> index e1930fdf..a7356e4a 100644
> --- a/Documentation/guides/pipeline-handler.rst
> +++ b/Documentation/guides/pipeline-handler.rst
> @@ -658,19 +658,31 @@ associated with immutable values, which represent static characteristics that ca
> be used by applications to identify camera devices in the system. Properties can be
> registered by inspecting the values of V4L2 controls from the video devices and
> camera sensor (for example to retrieve the position and orientation of a camera)
> -or to express other immutable characteristics. The example pipeline handler does
> -not register any property, but examples are available in the libcamera code
> -base.
> +or to express other immutable characteristics.
>
> -.. TODO: Add a property example to the pipeline handler. At least the model.
> +A required property is ``MinimumRequests``, which indicates how many requests
> +need to be queued in the pipeline for capture without frame drops to be
> +possible.
> +
> +In our case, the vivid driver requires two buffers before it'll start streaming
> +(can be seen in the ``min_buffers_needed`` property for the ``vid_cap`` queue in
> +vivid's driver code). In order to not drop frames we should have one extra
> +buffer queued to the driver so that it is used as soon as the previous buffer
> +completes. Therefore we will set our ``MinimumRequests`` to three. Append the
> +following line to ``init()``:
The driver requires two buffers to operate, why an extra one is needed ?
For vivid in particular, where buffer's content is generated..
> +
> +.. code-block:: cpp
> +
> + properties_.set(properties::MinimumRequests, 3);
>
> At this point you need to add the following includes to the top of the file for
> -handling controls:
> +handling controls and properties:
>
> .. code-block:: cpp
>
> #include <libcamera/controls.h>
> #include <libcamera/control_ids.h>
> + #include <libcamera/property_ids.h>
>
> Generating a default configuration
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> index e4d79ea4..98a4a3e5 100644
> --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> @@ -1126,6 +1126,8 @@ int PipelineHandlerIPU3::registerCameras()
> /* Initialize the camera properties. */
> data->properties_ = cio2->sensor()->properties();
>
> + data->properties_.set(properties::MinimumRequests, 3);
> +
I see
static constexpr unsigned int kBufferCount = 4;
Which seems to suggest that at least 4 buffers need to be queued to
the video device before streaming is started.
I wonder if I'm confusing the two concepts
> ret = initControls(data.get());
> if (ret)
> continue;
> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> index 8569df17..4a08d01e 100644
> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> @@ -1063,6 +1063,8 @@ int PipelineHandlerRPi::start(Camera *camera, const ControlList *controls)
> /* Enable SOF event generation. */
> data->unicam_[Unicam::Image].dev()->setFrameStartEnabled(true);
>
> + data->properties_.set(properties::MinimumRequests, 3);
> +
> /*
> * Reset the delayed controls with the gain and exposure values set by
> * the IPA.
> diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> index f658d75e..45b6beaf 100644
> --- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> +++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> @@ -23,6 +23,7 @@
> #include <libcamera/control_ids.h>
> #include <libcamera/formats.h>
> #include <libcamera/framebuffer.h>
> +#include <libcamera/property_ids.h>
> #include <libcamera/request.h>
> #include <libcamera/stream.h>
> #include <libcamera/ipa/core_ipa_interface.h>
> @@ -1102,6 +1103,7 @@ int PipelineHandlerRkISP1::createCamera(MediaEntity *sensor)
>
> /* Initialize the camera properties. */
> data->properties_ = data->sensor_->properties();
> + data->properties_.set(properties::MinimumRequests, 3);
Same question for RkISP1, it seems we don't even populate
StreamConfiguration::bufferCount there, but I'm pretty sure you need 4
requests queued before capture can start..
>
> /*
> * \todo Read dealy values from the sensor itself or from a
> diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
> index 24ded4db..8ed983fe 100644
> --- a/src/libcamera/pipeline/simple/simple.cpp
> +++ b/src/libcamera/pipeline/simple/simple.cpp
> @@ -25,6 +25,7 @@
>
> #include <libcamera/camera.h>
> #include <libcamera/control_ids.h>
> +#include <libcamera/property_ids.h>
> #include <libcamera/request.h>
> #include <libcamera/stream.h>
>
> @@ -180,6 +181,10 @@ class SimplePipelineHandler;
>
> struct SimplePipelineInfo {
> const char *driver;
> + /*
> + * Minimum number of buffers required by the driver to start streaming.
> + */
> + unsigned int minimumBuffers;
> /*
> * Each converter in the list contains the name
> * and the number of streams it supports.
> @@ -190,10 +195,10 @@ struct SimplePipelineInfo {
> namespace {
>
> static const SimplePipelineInfo supportedDevices[] = {
> - { "imx7-csi", { { "pxp", 1 } } },
> - { "mxc-isi", {} },
> - { "qcom-camss", {} },
> - { "sun6i-csi", {} },
> + { "imx7-csi", 2, { { "pxp", 1 } } },
> + { "mxc-isi", 3, {} },
> + { "qcom-camss", 1, {} },
> + { "sun6i-csi", 3, {} },
> };
>
> } /* namespace */
> @@ -271,6 +276,8 @@ public:
> bool useConverter_;
> std::queue<std::map<unsigned int, FrameBuffer *>> converterQueue_;
>
> + const SimplePipelineInfo *deviceInfo;
> +
> private:
> void tryPipeline(unsigned int code, const Size &size);
> static std::vector<const MediaPad *> routedSourcePads(MediaPad *sink);
> @@ -1168,6 +1175,29 @@ int SimplePipelineHandler::configure(Camera *camera, CameraConfiguration *c)
> inputCfg.stride = captureFormat.planes[0].bpl;
> inputCfg.bufferCount = kNumInternalBuffers;
>
> + /* Set the MinimumRequests property. */
> + unsigned int minimumRequests;
> +
> + if (data->useConverter_) {
> + /*
> + * The application will interact only with the capture node of
> + * the converter. Require two buffers for a frame drop free
> + * conversion, plus one extra to account for requeue delays.
> + */
> + minimumRequests = 3;
> + } else {
> + /*
> + * The application will interact directly with the video capture
> + * device. Require the minimum required by the driver, plus one
> + * extra to account for requeue delays. Force at least three
> + * buffers in order to not drop frames.
> + */
> + minimumRequests = std::max(data->deviceInfo->minimumBuffers + 1,
> + 3U);
> + }
> +
> + data->properties_.set(properties::MinimumRequests, minimumRequests);
> +
> return data->converter_->configure(inputCfg, outputCfgs);
> }
>
> @@ -1506,6 +1536,8 @@ bool SimplePipelineHandler::match(DeviceEnumerator *enumerator)
> bool registered = false;
>
> for (std::unique_ptr<SimpleCameraData> &data : pipelines) {
> + data->deviceInfo = info;
> +
> int ret = data->init();
> if (ret < 0)
> continue;
> diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> index 277465b7..7f580955 100644
> --- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> +++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
> @@ -500,6 +500,8 @@ int UVCCameraData::init(MediaDevice *media)
> properties_.set(properties::PixelArraySize, resolution);
> properties_.set(properties::PixelArrayActiveAreas, { Rectangle(resolution) });
>
> + properties_.set(properties::MinimumRequests, 3);
> +
> /* Initialise the supported controls. */
> ControlInfoMap::Map ctrls;
>
> diff --git a/src/libcamera/pipeline/vimc/vimc.cpp b/src/libcamera/pipeline/vimc/vimc.cpp
> index 204f5ad7..d2633be4 100644
> --- a/src/libcamera/pipeline/vimc/vimc.cpp
> +++ b/src/libcamera/pipeline/vimc/vimc.cpp
> @@ -21,6 +21,7 @@
> #include <libcamera/control_ids.h>
> #include <libcamera/controls.h>
> #include <libcamera/formats.h>
> +#include <libcamera/property_ids.h>
> #include <libcamera/request.h>
> #include <libcamera/stream.h>
>
> @@ -571,6 +572,7 @@ int VimcCameraData::init()
>
> /* Initialize the camera properties. */
> properties_ = sensor_->properties();
> + properties_.set(properties::MinimumRequests, 3);
>
> return 0;
> }
> diff --git a/src/libcamera/property_ids.yaml b/src/libcamera/property_ids.yaml
> index cb55e0ed..c82ac17e 100644
> --- a/src/libcamera/property_ids.yaml
> +++ b/src/libcamera/property_ids.yaml
> @@ -690,6 +690,27 @@ controls:
> that is twice that of the full resolution mode. This value will be valid
> after the configure method has returned successfully.
>
> + - MinimumRequests:
> + type: int32_t
> + description: |
> + The minimum number of capture requests that the camera pipeline requires
> + to have queued in order to sustain capture operations without frame
> + drops. At this quantity, there's no guarantee that manual per-frame
> + controls will apply correctly.
This property is also relevant for the startup phase, so mentioning
that this is the minium number of requests that need to be queued
before capture starts might be necessary ?
> +
> + This property is based on the minimum number of memory buffers
> + needed to fill the capture pipeline composed of hardware processing
> + blocks plus as many buffers as needed to take into account propagation
> + delays and avoid dropping frames.
> +
> + \todo Should this be a per-stream property?
> +
> + \todo Extend this property to expose the different minimum buffer and
> + request counts (the minimum number of buffers to be able to capture at
> + all, the minimum number of buffers to sustain capture without frame
> + drop, and the minimum number of requests to ensure proper operation of
> + per-frame controls).
> +
> # ----------------------------------------------------------------------------
> # Draft properties section
>
> --
> 2.35.1
>
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