[libcamera-devel] [PATCH v3 3/5] android: camera_device: Compute frame durations

[Laurent Pinchart]

Hi Jacopo,

Thank you for the patch.

On Mon, Feb 22, 2021 at 11:52:20AM +0100, Jacopo Mondi wrote:
> Use the FrameDuration control reported by pipeline handlers to register
> the Auto-Exposure routine FPS range, the minimum stream frame durations
> and the sensor maximum frame duration.
> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
>  src/android/camera_device.cpp | 84 ++++++++++++++++++++++++++---------
>  1 file changed, 64 insertions(+), 20 deletions(-)
> 
> diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> index 1e2a5b5f91da..1658e4a4dd9f 100644
> --- a/src/android/camera_device.cpp
> +++ b/src/android/camera_device.cpp
> @@ -9,6 +9,7 @@
>  #include "camera_ops.h"
>  #include "post_processor.h"
>  
> +#include <cmath>
>  #include <fstream>
>  #include <sys/mman.h>
>  #include <tuple>
> @@ -708,10 +709,10 @@ std::tuple<uint32_t, uint32_t> CameraDevice::calculateStaticMetadataSize()
>  {
>  	/*
>  	 * \todo Keep this in sync with the actual number of entries.
> -	 * Currently: 53 entries, 854 bytes of static metadata
> +	 * Currently: 54 entries, 874 bytes of static metadata
>  	 */
> -	uint32_t numEntries = 53;
> -	uint32_t byteSize = 854;
> +	uint32_t numEntries = 54;
> +	uint32_t byteSize = 874;
>  
>  	/*
>  	 * Calculate space occupation in bytes for dynamically built metadata
> @@ -801,12 +802,48 @@ const camera_metadata_t *CameraDevice::getStaticMetadata()
>  				  aeAvailableModes.data(),
>  				  aeAvailableModes.size());
>  
> -	std::vector<int32_t> availableAeFpsTarget = {
> -		15, 30,
> -	};
> -	staticMetadata_->addEntry(ANDROID_CONTROL_AE_AVAILABLE_TARGET_FPS_RANGES,
> -				  availableAeFpsTarget.data(),
> -				  availableAeFpsTarget.size());
> +	int64_t minFrameDurationNsec = -1;
> +	int64_t maxFrameDurationNsec = -1;
> +	const auto frameDurationsInfo = controlsInfo.find(&controls::FrameDurations);
> +	if (frameDurationsInfo != controlsInfo.end()) {
> +		minFrameDurationNsec = frameDurationsInfo->second.min().get<int64_t>() * 1000;
> +		maxFrameDurationNsec = frameDurationsInfo->second.max().get<int64_t>() * 1000;
> +
> +		/*
> +		 * Adjust the minimum frame duration to comply with Android
> +		 * requirements. The camera service mandates all preview/record
> +		 * streams to have a minimum frame duration < 33,366 milliseconds
> +		 * (see MAX_PREVIEW_RECORD_DURATION_NS in the camera service
> +		 * implementation).
> +		 *
> +		 * If we're close enough (+ 500 useconds) to that value, round
> +		 * the minimum frame duration of the camera to an accepted
> +		 * value.
> +		 */
> +		static constexpr int64_t MAX_PREVIEW_RECORD_DURATION_NS = 1e9 / 29.97;
> +		if (minFrameDurationNsec > MAX_PREVIEW_RECORD_DURATION_NS &&
> +		    minFrameDurationNsec < MAX_PREVIEW_RECORD_DURATION_NS + 500000)
> +			minFrameDurationNsec = MAX_PREVIEW_RECORD_DURATION_NS - 1000;
> +
> +		/*
> +		 * The AE routine frame rate limits are computed using the frame
> +		 * duration limits, as libcamera clips the AE routine to the
> +		 * frame durations.
> +		 */
> +		int32_t maxFps = static_cast<int32_t>(std::round(1e9 / minFrameDurationNsec));
> +		int32_t minFps = static_cast<int32_t>(std::round(1e9 / maxFrameDurationNsec));

Are the explicit casts needed ? I don't get any compilation failure in
my tests, but maybe the runtime behaviour isn't correct ?

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> +		minFps = std::max(1, minFps);
> +
> +		/*
> +		 * Register to the camera service {min, max} and {max, max}
> +		 * intervals as requested by the metadata documentation.
> +		 */
> +		int32_t availableAeFpsTarget[] = {
> +			minFps, maxFps, maxFps, maxFps
> +		};
> +		staticMetadata_->addEntry(ANDROID_CONTROL_AE_AVAILABLE_TARGET_FPS_RANGES,
> +					  availableAeFpsTarget, 4);
> +	}
>  
>  	std::vector<int32_t> aeCompensationRange = {
>  		0, 0,
> @@ -996,6 +1033,10 @@ const camera_metadata_t *CameraDevice::getStaticMetadata()
>  	staticMetadata_->addEntry(ANDROID_SENSOR_INFO_TIMESTAMP_SOURCE,
>  				  &timestampSource, 1);
>  
> +	if (maxFrameDurationNsec > 0)
> +		staticMetadata_->addEntry(ANDROID_SENSOR_INFO_MAX_FRAME_DURATION,
> +					  &maxFrameDurationNsec, 1);
> +
>  	/* Statistics static metadata. */
>  	uint8_t faceDetectMode = ANDROID_STATISTICS_FACE_DETECT_MODE_OFF;
>  	staticMetadata_->addEntry(ANDROID_STATISTICS_INFO_AVAILABLE_FACE_DETECT_MODES,
> @@ -1130,18 +1171,20 @@ const camera_metadata_t *CameraDevice::getStaticMetadata()
>  				  availableStallDurations.data(),
>  				  availableStallDurations.size());
>  
> -	/* \todo Collect the minimum frame duration from the camera. */
> -	std::vector<int64_t> minFrameDurations;
> -	minFrameDurations.reserve(streamConfigurations_.size() * 4);
> -	for (const auto &entry : streamConfigurations_) {
> -		minFrameDurations.push_back(entry.androidFormat);
> -		minFrameDurations.push_back(entry.resolution.width);
> -		minFrameDurations.push_back(entry.resolution.height);
> -		minFrameDurations.push_back(33333333);
> +	/* Use the minimum frame duration for all the YUV/RGB formats. */
> +	if (minFrameDurationNsec > 0) {
> +		std::vector<int64_t> minFrameDurations;
> +		minFrameDurations.reserve(streamConfigurations_.size() * 4);
> +		for (const auto &entry : streamConfigurations_) {
> +			minFrameDurations.push_back(entry.androidFormat);
> +			minFrameDurations.push_back(entry.resolution.width);
> +			minFrameDurations.push_back(entry.resolution.height);
> +			minFrameDurations.push_back(minFrameDurationNsec);
> +		}
> +		staticMetadata_->addEntry(ANDROID_SCALER_AVAILABLE_MIN_FRAME_DURATIONS,
> +					  minFrameDurations.data(),
> +					  minFrameDurations.size());
>  	}
> -	staticMetadata_->addEntry(ANDROID_SCALER_AVAILABLE_MIN_FRAME_DURATIONS,
> -				  minFrameDurations.data(),
> -				  minFrameDurations.size());
>  
>  	uint8_t croppingType = ANDROID_SCALER_CROPPING_TYPE_CENTER_ONLY;
>  	staticMetadata_->addEntry(ANDROID_SCALER_CROPPING_TYPE, &croppingType, 1);
> @@ -1241,6 +1284,7 @@ const camera_metadata_t *CameraDevice::getStaticMetadata()
>  		ANDROID_SENSOR_INFO_ACTIVE_ARRAY_SIZE,
>  		ANDROID_SENSOR_INFO_COLOR_FILTER_ARRANGEMENT,
>  		ANDROID_SENSOR_INFO_EXPOSURE_TIME_RANGE,
> +		ANDROID_SENSOR_INFO_MAX_FRAME_DURATION,
>  		ANDROID_SENSOR_INFO_PHYSICAL_SIZE,
>  		ANDROID_SENSOR_INFO_PIXEL_ARRAY_SIZE,
>  		ANDROID_SENSOR_INFO_SENSITIVITY_RANGE,

-- 
Regards,

Laurent Pinchart