[libcamera-devel] [PATCH v6 5/7] android: Track and notify post processing of streams

Laurent Pinchart laurent.pinchart at ideasonboard.com
Mon Oct 25 15:53:45 CEST 2021


Hi Umang,

On Mon, Oct 25, 2021 at 07:16:56PM +0530, Umang Jain wrote:
> On 10/25/21 6:55 PM, Laurent Pinchart wrote:
> > On Mon, Oct 25, 2021 at 06:46:39PM +0530, Umang Jain wrote:
> >> On 10/25/21 11:33 AM, Laurent Pinchart wrote:
> >>> On Sat, Oct 23, 2021 at 04:03:00PM +0530, Umang Jain wrote:
> >>>> Notify that the post processing for a request has been completed,
> >>>> via a signal. The signal emit with a context pointer along with status
> >>> s/emit/is emitted/ ?
> >>>
> >>>> of the buffer. The function CameraDevice::streamProcessingComplete() will
> >>>> finally set the status on the request descriptor and complete the
> >>>> descriptor if all the streams requiring post processing are completed.
> >>>> If buffer status obtained is in error state, notify the status to the
> >>>> framework and set the overall error status on the descriptor via
> >>>> setBufferStatus().
> >>>>
> >>>> We need to track the number of streams requiring post-processing
> >>>> per Camera3RequestDescriptor (i.e. per capture request). Introduce
> >>>> a std::map<> to track the post-processing of streams. The nodes
> >>>> are dropped from the map when a particular stream post processing
> >>>> is completed (or on error paths). A std::map is selected for tracking
> >>>> post-processing requests, since we will move post-processing to be
> >>>> asynchronous in subsequent commits. A vector or queue will not be
> >>>> suitable then as the sequential order of post-processing completion
> >>>> of various requests won't be guaranteed then.
> >>>>
> >>>> A streamProcessMutex_ has been introduced here as well, which will be
> >>> s/streamProcessMutex_/streamsProcessMutex_/
> >>>
> >>>> applicable to guard access to descriptor's pendingStreamsToProcess_ when
> >>>> post-processing is moved to be asynchronous in subsequent commits.
> >>>>
> >>>> Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
> >>>> ---
> >>>>    src/android/camera_device.cpp            | 95 ++++++++++++++++++------
> >>>>    src/android/camera_device.h              |  4 +
> >>>>    src/android/camera_request.h             |  6 ++
> >>>>    src/android/camera_stream.cpp            | 15 ++++
> >>>>    src/android/jpeg/post_processor_jpeg.cpp |  2 +
> >>>>    src/android/post_processor.h             |  9 +++
> >>>>    src/android/yuv/post_processor_yuv.cpp   |  8 +-
> >>>>    7 files changed, 114 insertions(+), 25 deletions(-)
> >>>>
> >>>> diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> >>>> index 2a98a2e6..3114def0 100644
> >>>> --- a/src/android/camera_device.cpp
> >>>> +++ b/src/android/camera_device.cpp
> >>>> @@ -926,6 +926,8 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
> >>>>    			 * Request.
> >>>>    			 */
> >>>>    			LOG(HAL, Debug) << ss.str() << " (mapped)";
> >>> Blank line here, or no blank line below.
> >>>
> >>>> +			descriptor->pendingStreamsToProcess_.insert(
> >>>> +				{ cameraStream, &buffer });
> >>>>    			continue;
> >>>>    
> >>>>    		case CameraStream::Type::Direct:
> >>>> @@ -955,6 +957,9 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
> >>>>    			frameBuffer = cameraStream->getBuffer();
> >>>>    			buffer.internalBuffer = frameBuffer;
> >>>>    			LOG(HAL, Debug) << ss.str() << " (internal)";
> >>>> +
> >>>> +			descriptor->pendingStreamsToProcess_.insert(
> >>>> +				{ cameraStream, &buffer });
> >>>>    			break;
> >>>>    		}
> >>>>    
> >>>> @@ -1118,43 +1123,46 @@ void CameraDevice::requestComplete(Request *request)
> >>>>    	}
> >>>>    
> >>>>    	/* Handle post-processing. */
> >>>> -	bool hasPostProcessingErrors = false;
> >>>> -	for (auto &buffer : descriptor->buffers_) {
> >>>> -		CameraStream *stream = buffer.stream;
> >>>> -
> >>>> -		if (stream->type() == CameraStream::Type::Direct)
> >>>> -			continue;
> >>>> +	bool needPostProcessing = false;
> >>>> +	/*
> >>>> +	 * \todo Protect the loop below with streamProcessMutex_ when post
> >>>> +	 * processor runs asynchronously.
> >>>> +	 */
> >>>> +	auto iter = descriptor->pendingStreamsToProcess_.begin();
> >>>> +	while (descriptor->pendingStreamsToProcess_.size() > 0) {
> >>> 	while (!descriptor->pendingStreamsToProcess_.empty()) {
> >>>
> >>> But it's not correct. The fix is in 7/7:
> >>>
> >>> 	while (iter != descriptor->pendingStreamsToProcess_.end()) {
> >> Yes, it was a tricky to handle the loop for async and sync variations
> >>
> >> For the async one, iter == end() was the only choice I  believe (Without
> >> introducing a counter)
> >>
> >>>> +		CameraStream *stream = iter->first;
> >>>> +		Camera3RequestDescriptor::StreamBuffer *buffer = iter->second;
> >>>> +		needPostProcessing = true;
> >>>>    
> >>>>    		FrameBuffer *src = request->findBuffer(stream->stream());
> >>>>    		if (!src) {
> >>>>    			LOG(HAL, Error) << "Failed to find a source stream buffer";
> >>>> -			buffer.status = Camera3RequestDescriptor::Status::Error;
> >>>> -			notifyError(descriptor->frameNumber_, stream->camera3Stream(),
> >>>> -				    CAMERA3_MSG_ERROR_BUFFER);
> >>>> -			hasPostProcessingErrors = true;
> >>>> +			setBufferStatus(*buffer, Camera3RequestDescriptor::Status::Error);
> >>>> +			iter = descriptor->pendingStreamsToProcess_.erase(iter);
> >>>>    			continue;
> >>>>    		}
> >>>>    
> >>>> -		int ret = stream->process(*src, buffer);
> >>>> +		++iter;
> >>>> +		int ret = stream->process(*src, *buffer);
> >>>> +		if (ret) {
> >>>> +			setBufferStatus(*buffer, Camera3RequestDescriptor::Status::Error);
> >>>> +			descriptor->pendingStreamsToProcess_.erase(stream);
> >>>> +		}
> >>>> +	}
> >>>>    
> >>>> +	if (needPostProcessing) {
> >>>>    		/*
> >>>> -		 * If the framebuffer is internal to CameraStream return it back
> >>>> -		 * now that we're done processing it.
> >>>> +		 * \todo We will require to check if we failed to queue
> >>>> +		 * post-processing requests when we migrate to post-processor
> >>>> +		 * running asynchronously.
> >>>> +		 *
> >>>> +		 * if (descriptor->pendingStreamsToProcess_.size() == 0)
> >>>> +		 *	completeDescriptor(descriptor);
> >>> Can't we do this already here ? I think you can actually drop the
> >>> needPostProcessing variable and just write
> >>>
> >>> 	if (descriptor->pendingStreamsToProcess_.empty())
> >>> 		completeDescriptor(descriptor);
> >>>
> >>> as needPostProcessing can only be false if pendingStreamsToProcess_ was
> >>> empty before the while loop above, and it will thus be empty after the
> >>> loop as well in that case.
> >> True, but we need needPostProcessing variable for async.
> > Why is that ? Won't
> >
> >   	if (descriptor->pendingStreamsToProcess_.empty())
> >   		completeDescriptor(descriptor);
> >
> > work in async mode too ?
> 
> 
> Ok yes, it should work (sorry I confused myself a bit, thinking it's 
> will be a double completeDescriptor(descriptor) for the same descriptor, 
> in case post-processing completes early when main thread reaches this 
> line. But I forgot that we are already holding a lock restricted slots 
> to run)
> 
> We would end up requestComplete() like: https://paste.debian.net/1216820/

With

	descriptor->pendingStreamsToProcess_.size() == 0

replaced with

	descriptor->pendingStreamsToProcess_.empty()

it seems good to me.

> >> I pre-empted
> >> its introduction deliberately to set the design beforehand andthen,  I
> >> can introduce async bits with minimal diff for
> >> CamreraDevice::requestComplete()
> >>
> >>>>    		 */
> >>>> -		if (buffer.internalBuffer)
> >>>> -			stream->putBuffer(buffer.internalBuffer);
> >>>>    
> >>>> -		if (ret) {
> >>>> -			buffer.status = Camera3RequestDescriptor::Status::Error;
> >>>> -			hasPostProcessingErrors = true;
> >>>> -			notifyError(descriptor->frameNumber_, stream->camera3Stream(),
> >>>> -				    CAMERA3_MSG_ERROR_BUFFER);
> >>>> -		}
> >>>> +		return;
> >>>>    	}
> >>>>    
> >>>> -	if (hasPostProcessingErrors)
> >>>> -		descriptor->status_ = Camera3RequestDescriptor::Status::Error;
> >>>> -
> >>>>    	completeDescriptor(descriptor);
> >>>>    }
> >>>>    
> >>>> @@ -1210,6 +1218,45 @@ void CameraDevice::sendCaptureResults()
> >>>>    	}
> >>>>    }
> >>>>    
> >>>> +void CameraDevice::setBufferStatus(Camera3RequestDescriptor::StreamBuffer &streamBuffer,
> >>>> +				   Camera3RequestDescriptor::Status status)
> >>>> +{
> >>>> +	/*
> >>>> +	 * If the framebuffer is internal to CameraStream return it back now
> >>>> +	 * that we're done processing it.
> >>>> +	 */
> >>>> +	if (streamBuffer.internalBuffer)
> >>>> +		streamBuffer.stream->putBuffer(streamBuffer.internalBuffer);
> >>> I'd move this to the caller, as it's not about the buffer status.
> >>>
> >>>> +
> >>>> +	streamBuffer.status = status;
> >>>> +	if (status != Camera3RequestDescriptor::Status::Success) {
> >>>> +		notifyError(streamBuffer.request->frameNumber_,
> >>>> +			    streamBuffer.stream->camera3Stream(),
> >>>> +			    CAMERA3_MSG_ERROR_BUFFER);
> >>>> +
> >>>> +		/* Also set error status on entire request descriptor. */
> >>>> +		streamBuffer.request->status_ =
> >>>> +			Camera3RequestDescriptor::Status::Error;
> >>>> +	}
> >>>> +}
> >>>> +
> >>>> +void CameraDevice::streamProcessingComplete(Camera3RequestDescriptor::StreamBuffer *streamBuffer,
> >>>> +					    Camera3RequestDescriptor::Status status)
> >>>> +{
> >>>> +	Camera3RequestDescriptor *request = streamBuffer->request;
> >>>> +	MutexLocker locker(request->streamsProcessMutex_);
> >>>> +
> >>>> +	setBufferStatus(*streamBuffer, status);
> >>> Do we need to protect the setBufferStatus() call with
> >>> streamsProcessMutex_ ? I thought it only protects
> >>> pendingStreamsToProcess_.
> >>
> >> Ah, I don't see why we need to lock it. This is a good catch.
> >>
> >> For the async version, the main thread isn't expected to call
> >> setBufferStatus() on the same descriptor (because we are already
> >> handling synchronous errors beforehand), so I don't expect to race. So I
> >> should remove setBufferStatus() from the lock section.
> >>
> >>>> +	request->pendingStreamsToProcess_.erase(streamBuffer->stream);
> >>>> +
> >>>> +	if (request->pendingStreamsToProcess_.size() > 0)
> >>> 	if (!request->pendingStreamsToProcess_.empty())
> >>>
> >>>> +		return;
> >>>> +
> >>>> +	locker.unlock();
> >>>> +
> >>>> +	completeDescriptor(streamBuffer->request);
> >>>> +}
> >>>> +
> >>>>    std::string CameraDevice::logPrefix() const
> >>>>    {
> >>>>    	return "'" + camera_->id() + "'";
> >>>> diff --git a/src/android/camera_device.h b/src/android/camera_device.h
> >>>> index e544f2bd..2a414020 100644
> >>>> --- a/src/android/camera_device.h
> >>>> +++ b/src/android/camera_device.h
> >>>> @@ -66,6 +66,8 @@ public:
> >>>>    	int configureStreams(camera3_stream_configuration_t *stream_list);
> >>>>    	int processCaptureRequest(camera3_capture_request_t *request);
> >>>>    	void requestComplete(libcamera::Request *request);
> >>>> +	void streamProcessingComplete(Camera3RequestDescriptor::StreamBuffer *bufferStream,
> >>>> +				      Camera3RequestDescriptor::Status status);
> >>>>    
> >>>>    protected:
> >>>>    	std::string logPrefix() const override;
> >>>> @@ -95,6 +97,8 @@ private:
> >>>>    	int processControls(Camera3RequestDescriptor *descriptor);
> >>>>    	void completeDescriptor(Camera3RequestDescriptor *descriptor);
> >>>>    	void sendCaptureResults();
> >>>> +	void setBufferStatus(Camera3RequestDescriptor::StreamBuffer &buffer,
> >>>> +			     Camera3RequestDescriptor::Status status);
> >>>>    	std::unique_ptr<CameraMetadata> getResultMetadata(
> >>>>    		const Camera3RequestDescriptor &descriptor) const;
> >>>>    
> >>>> diff --git a/src/android/camera_request.h b/src/android/camera_request.h
> >>>> index c4bc5d6e..cc2b7035 100644
> >>>> --- a/src/android/camera_request.h
> >>>> +++ b/src/android/camera_request.h
> >>>> @@ -7,7 +7,9 @@
> >>>>    #ifndef __ANDROID_CAMERA_REQUEST_H__
> >>>>    #define __ANDROID_CAMERA_REQUEST_H__
> >>>>    
> >>>> +#include <map>
> >>>>    #include <memory>
> >>>> +#include <mutex>
> >>>>    #include <vector>
> >>>>    
> >>>>    #include <libcamera/base/class.h>
> >>>> @@ -43,6 +45,10 @@ public:
> >>>>    		Camera3RequestDescriptor *request;
> >>>>    	};
> >>>>    
> >>>> +	/* Keeps track of streams requiring post-processing. */
> >>>> +	std::map<CameraStream *, StreamBuffer *> pendingStreamsToProcess_;
> >>>> +	std::mutex streamsProcessMutex_;
> >>>> +
> >>>>    	Camera3RequestDescriptor(libcamera::Camera *camera,
> >>>>    				 const camera3_capture_request_t *camera3Request);
> >>>>    	~Camera3RequestDescriptor();
> >>>> diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> >>>> index 0e268cdf..4e275cde 100644
> >>>> --- a/src/android/camera_stream.cpp
> >>>> +++ b/src/android/camera_stream.cpp
> >>>> @@ -22,6 +22,7 @@
> >>>>    #include "camera_capabilities.h"
> >>>>    #include "camera_device.h"
> >>>>    #include "camera_metadata.h"
> >>>> +#include "post_processor.h"
> >>>>    
> >>>>    using namespace libcamera;
> >>>>    
> >>>> @@ -97,6 +98,20 @@ int CameraStream::configure()
> >>>>    		int ret = postProcessor_->configure(configuration(), output);
> >>>>    		if (ret)
> >>>>    			return ret;
> >>>> +
> >>>> +		postProcessor_->processComplete.connect(
> >>>> +			this, [&](Camera3RequestDescriptor::StreamBuffer *streamBuffer,
> >>>> +				  PostProcessor::Status status) {
> >>>> +				Camera3RequestDescriptor::Status bufferStatus;
> >>>> +
> >>>> +				if (status == PostProcessor::Status::Success)
> >>>> +					bufferStatus = Camera3RequestDescriptor::Status::Success;
> >>>> +				else
> >>>> +					bufferStatus = Camera3RequestDescriptor::Status::Error;
> >>>> +
> >>>> +				cameraDevice_->streamProcessingComplete(streamBuffer,
> >>>> +									bufferStatus);
> >>>> +			});
> >>>>    	}
> >>>>    
> >>>>    	if (type_ == Type::Internal) {
> >>>> diff --git a/src/android/jpeg/post_processor_jpeg.cpp b/src/android/jpeg/post_processor_jpeg.cpp
> >>>> index da71f113..cbbe7128 100644
> >>>> --- a/src/android/jpeg/post_processor_jpeg.cpp
> >>>> +++ b/src/android/jpeg/post_processor_jpeg.cpp
> >>>> @@ -198,6 +198,7 @@ int PostProcessorJpeg::process(Camera3RequestDescriptor::StreamBuffer *streamBuf
> >>>>    					 exif.data(), quality);
> >>>>    	if (jpeg_size < 0) {
> >>>>    		LOG(JPEG, Error) << "Failed to encode stream image";
> >>>> +		processComplete.emit(streamBuffer, PostProcessor::Status::Error);
> >>>>    		return jpeg_size;
> >>>>    	}
> >>>>    
> >>>> @@ -211,6 +212,7 @@ int PostProcessorJpeg::process(Camera3RequestDescriptor::StreamBuffer *streamBuf
> >>>>    
> >>>>    	/* Update the JPEG result Metadata. */
> >>>>    	resultMetadata->addEntry(ANDROID_JPEG_SIZE, jpeg_size);
> >>>> +	processComplete.emit(streamBuffer, PostProcessor::Status::Success);
> >>>>    
> >>>>    	return 0;
> >>>>    }
> >>>> diff --git a/src/android/post_processor.h b/src/android/post_processor.h
> >>>> index 128161c8..4ac74fcf 100644
> >>>> --- a/src/android/post_processor.h
> >>>> +++ b/src/android/post_processor.h
> >>>> @@ -7,6 +7,8 @@
> >>>>    #ifndef __ANDROID_POST_PROCESSOR_H__
> >>>>    #define __ANDROID_POST_PROCESSOR_H__
> >>>>    
> >>>> +#include <libcamera/base/signal.h>
> >>>> +
> >>>>    #include <libcamera/framebuffer.h>
> >>>>    #include <libcamera/stream.h>
> >>>>    
> >>>> @@ -16,11 +18,18 @@
> >>>>    class PostProcessor
> >>>>    {
> >>>>    public:
> >>>> +	enum class Status {
> >>>> +		Error,
> >>>> +		Success
> >>>> +	};
> >>>> +
> >>>>    	virtual ~PostProcessor() = default;
> >>>>    
> >>>>    	virtual int configure(const libcamera::StreamConfiguration &inCfg,
> >>>>    			      const libcamera::StreamConfiguration &outCfg) = 0;
> >>>>    	virtual int process(Camera3RequestDescriptor::StreamBuffer *streamBuffer) = 0;
> >>>> +
> >>>> +	libcamera::Signal<Camera3RequestDescriptor::StreamBuffer *, Status> processComplete;
> >>>>    };
> >>>>    
> >>>>    #endif /* __ANDROID_POST_PROCESSOR_H__ */
> >>>> diff --git a/src/android/yuv/post_processor_yuv.cpp b/src/android/yuv/post_processor_yuv.cpp
> >>>> index eeb8f1f4..8e77bf57 100644
> >>>> --- a/src/android/yuv/post_processor_yuv.cpp
> >>>> +++ b/src/android/yuv/post_processor_yuv.cpp
> >>>> @@ -54,12 +54,15 @@ int PostProcessorYuv::process(Camera3RequestDescriptor::StreamBuffer *streamBuff
> >>>>    	const FrameBuffer &source = *streamBuffer->srcBuffer;
> >>>>    	CameraBuffer *destination = streamBuffer->destBuffer.get();
> >>>>    
> >>>> -	if (!isValidBuffers(source, *destination))
> >>>> +	if (!isValidBuffers(source, *destination)) {
> >>>> +		processComplete.emit(streamBuffer, PostProcessor::Status::Error);
> >>>>    		return -EINVAL;
> >>>> +	}
> >>>>    
> >>>>    	const MappedFrameBuffer sourceMapped(&source, MappedFrameBuffer::MapFlag::Read);
> >>>>    	if (!sourceMapped.isValid()) {
> >>>>    		LOG(YUV, Error) << "Failed to mmap camera frame buffer";
> >>>> +		processComplete.emit(streamBuffer, PostProcessor::Status::Error);
> >>>>    		return -EINVAL;
> >>>>    	}
> >>>>    
> >>>> @@ -77,9 +80,12 @@ int PostProcessorYuv::process(Camera3RequestDescriptor::StreamBuffer *streamBuff
> >>>>    				    libyuv::FilterMode::kFilterBilinear);
> >>>>    	if (ret) {
> >>>>    		LOG(YUV, Error) << "Failed NV12 scaling: " << ret;
> >>>> +		processComplete.emit(streamBuffer, PostProcessor::Status::Error);
> >>>>    		return -EINVAL;
> >>>>    	}
> >>>>    
> >>>> +	processComplete.emit(streamBuffer, PostProcessor::Status::Success);
> >>>> +
> >>>>    	return 0;
> >>>>    }
> >>>>    

-- 
Regards,

Laurent Pinchart


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