[libcamera-devel] [PATCH 09/20] libcamera: pipeline: simple: converter: Add multi-stream support

paul.elder at ideasonboard.com paul.elder at ideasonboard.com
Tue Mar 2 01:11:20 CET 2021


Hi Laurent and Kieran,

On Tue, Mar 02, 2021 at 12:19:02AM +0200, Laurent Pinchart wrote:
> Hi Kieran,
> 
> On Mon, Feb 22, 2021 at 01:08:12PM +0000, Kieran Bingham wrote:
> > On 31/01/2021 22:46, Laurent Pinchart wrote:
> > > While the M2M device backing the converter doesn't support multiple
> > > streams natively, it can be run once per stream to produce multiple
> > > outputs from the same input, with different output formats and sizes.
> > 
> > Well, that's going to get a bit more fun ;-)
> > 
> > > To support this, create a class to model a stream and move control of
> > > the M2M device to the Stream class. The SimpleConverter class then
> > > creates stream instances and iterates over them. Each stream needs its
> > > own instance of the V4L2M2MDevice, to support different output
> > > configurations. The SimpleConverter class retains a device instance to
> > > support the query operations.
> > 
> > This reminds me of a discussion on linux-media, where having multiple
> > opens of an M2M device gets quite difficult to distinguish between the
> > different opened contexts in the kernel debug messages. Each queue has a
> > different type, but the separate open contexts are harder to distinguish.
> > 
> > I hope our multiple streams log outputs can be clearly separated
> > (presumably with a stream index)?
> 
> Good point... Seems I need to fix that :-)
> 
> Beside handling this in the converter, we could print the fd in
> V4L2VideoDevice::logPrefix(), do you think that would be useful ?

Ooh yeah I think that's a good idea.

> > > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > > ---
> > >  src/libcamera/pipeline/simple/converter.cpp | 294 ++++++++++++++------
> > >  src/libcamera/pipeline/simple/converter.h   |  44 ++-
> > >  src/libcamera/pipeline/simple/simple.cpp    |   6 +-
> > >  3 files changed, 250 insertions(+), 94 deletions(-)
> > > 
> > > diff --git a/src/libcamera/pipeline/simple/converter.cpp b/src/libcamera/pipeline/simple/converter.cpp
> > > index 8324baedc198..3db162d9edb8 100644
> > > --- a/src/libcamera/pipeline/simple/converter.cpp
> > > +++ b/src/libcamera/pipeline/simple/converter.cpp
> > > @@ -17,12 +17,157 @@
> > >  
> > >  #include "libcamera/internal/log.h"
> > >  #include "libcamera/internal/media_device.h"
> > > +#include "libcamera/internal/utils.h"
> > >  #include "libcamera/internal/v4l2_videodevice.h"
> > >  
> > >  namespace libcamera {
> > >  
> > >  LOG_DECLARE_CATEGORY(SimplePipeline)
> > >  
> > > +/* -----------------------------------------------------------------------------
> > > + * SimpleConverter::Stream
> > > + */
> > > +
> > > +SimpleConverter::Stream::Stream(SimpleConverter *converter)
> > > +	: converter_(converter)
> > > +{
> > > +	m2m_ = std::make_unique<V4L2M2MDevice>(converter->deviceNode_);
> > > +
> > > +	m2m_->output()->bufferReady.connect(this, &Stream::outputBufferReady);
> > > +	m2m_->capture()->bufferReady.connect(this, &Stream::captureBufferReady);
> > > +
> > > +	int ret = m2m_->open();
> > > +	if (ret < 0)
> > > +		m2m_.reset();
> > > +}
> > > +
> > > +int SimpleConverter::Stream::configure(const StreamConfiguration &inputCfg,
> > > +				       const StreamConfiguration &outputCfg)
> > > +{
> > > +	V4L2PixelFormat videoFormat =
> > > +		m2m_->output()->toV4L2PixelFormat(inputCfg.pixelFormat);
> > > +
> > > +	V4L2DeviceFormat format;
> > > +	format.fourcc = videoFormat;
> > > +	format.size = inputCfg.size;
> > > +	format.planesCount = 1;
> > > +	format.planes[0].bpl = inputCfg.stride;
> > > +
> > > +	int ret = m2m_->output()->setFormat(&format);
> > > +	if (ret < 0) {
> > > +		LOG(SimplePipeline, Error)
> > > +			<< "Failed to set input format: " << strerror(-ret);
> > > +		return ret;
> > > +	}
> > > +
> > > +	if (format.fourcc != videoFormat || format.size != inputCfg.size ||
> > > +	    format.planes[0].bpl != inputCfg.stride) {
> > > +		LOG(SimplePipeline, Error)
> > > +			<< "Input format not supported";
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	/* Set the pixel format and size on the output. */
> > > +	videoFormat = m2m_->capture()->toV4L2PixelFormat(outputCfg.pixelFormat);
> > > +	format = {};
> > > +	format.fourcc = videoFormat;
> > > +	format.size = outputCfg.size;

Why doesn't the output need plane information?

> > > +
> > > +	ret = m2m_->capture()->setFormat(&format);
> > > +	if (ret < 0) {
> > > +		LOG(SimplePipeline, Error)
> > > +			<< "Failed to set output format: " << strerror(-ret);
> > > +		return ret;
> > > +	}
> > > +
> > > +	if (format.fourcc != videoFormat || format.size != outputCfg.size) {
> > > +		LOG(SimplePipeline, Error)
> > > +			<< "Output format not supported";
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	inputBufferCount_ = inputCfg.bufferCount;
> > > +	outputBufferCount_ = outputCfg.bufferCount;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +int SimpleConverter::Stream::exportBuffers(unsigned int count,
> > > +					   std::vector<std::unique_ptr<FrameBuffer>> *buffers)
> > > +{
> > > +	return m2m_->capture()->exportBuffers(count, buffers);
> > > +}
> > > +
> > > +int SimpleConverter::Stream::start()
> > > +{
> > > +	int ret = m2m_->output()->importBuffers(inputBufferCount_);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	ret = m2m_->capture()->importBuffers(outputBufferCount_);
> > > +	if (ret < 0) {
> > > +		stop();
> > > +		return ret;
> > > +	}
> > > +
> > > +	ret = m2m_->output()->streamOn();
> > > +	if (ret < 0) {
> > > +		stop();
> > > +		return ret;
> > > +	}
> > > +
> > > +	ret = m2m_->capture()->streamOn();
> > > +	if (ret < 0) {
> > > +		stop();
> > > +		return ret;
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +void SimpleConverter::Stream::stop()
> > > +{
> > > +	m2m_->capture()->streamOff();
> > > +	m2m_->output()->streamOff();
> > > +	m2m_->capture()->releaseBuffers();
> > > +	m2m_->output()->releaseBuffers();
> > > +}
> > > +
> > > +int SimpleConverter::Stream::queueBuffers(FrameBuffer *input,
> > > +					  FrameBuffer *output)
> > > +{
> > > +	int ret = m2m_->output()->queueBuffer(input);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	ret = m2m_->capture()->queueBuffer(output);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +void SimpleConverter::Stream::outputBufferReady(FrameBuffer *buffer)
> > > +{
> > > +	auto it = converter_->queue_.find(buffer);
> > > +	if (it == converter_->queue_.end())
> > > +		return;
> > > +
> > > +	if (!--it->second) {
> > > +		converter_->inputBufferReady.emit(buffer);
> > > +		converter_->queue_.erase(it);
> > > +	}
> > > +}
> > > +
> > > +void SimpleConverter::Stream::captureBufferReady(FrameBuffer *buffer)
> > > +{
> > > +	converter_->outputBufferReady.emit(buffer);
> > > +}
> > > +
> > > +/* -----------------------------------------------------------------------------
> > > + * SimpleConverter
> > > + */
> > > +
> > >  SimpleConverter::SimpleConverter(MediaDevice *media)
> > >  {
> > >  	/*
> > > @@ -37,16 +182,14 @@ SimpleConverter::SimpleConverter(MediaDevice *media)
> > >  	if (it == entities.end())
> > >  		return;
> > >  
> > > -	m2m_ = std::make_unique<V4L2M2MDevice>((*it)->deviceNode());
> > > +	deviceNode_ = (*it)->deviceNode();
> > >  
> > > +	m2m_ = std::make_unique<V4L2M2MDevice>(deviceNode_);
> > >  	int ret = m2m_->open();
> > >  	if (ret < 0) {
> > >  		m2m_.reset();
> > >  		return;
> > >  	}
> > > -
> > > -	m2m_->output()->bufferReady.connect(this, &SimpleConverter::m2mInputBufferReady);
> > > -	m2m_->capture()->bufferReady.connect(this, &SimpleConverter::m2mOutputBufferReady);
> > >  }
> > >  
> > >  std::vector<PixelFormat> SimpleConverter::formats(PixelFormat input)
> > > @@ -141,86 +284,54 @@ SimpleConverter::strideAndFrameSize(const PixelFormat &pixelFormat,
> > >  }
> > >  
> > >  int SimpleConverter::configure(const StreamConfiguration &inputCfg,
> > > -			       const StreamConfiguration &outputCfg)
> > > +			       const std::vector<std::reference_wrapper<StreamConfiguration>> &outputCfgs)
> > >  {
> > > -	int ret;
> > > +	int ret = 0;
> > >  
> > > -	V4L2PixelFormat videoFormat =
> > > -		m2m_->output()->toV4L2PixelFormat(inputCfg.pixelFormat);
> > > +	streams_.clear();
> > > +	streams_.reserve(outputCfgs.size());
> > >  
> > > -	V4L2DeviceFormat format;
> > > -	format.fourcc = videoFormat;
> > > -	format.size = inputCfg.size;
> > > -	format.planesCount = 1;
> > > -	format.planes[0].bpl = inputCfg.stride;
> > > +	for (const StreamConfiguration &outputCfg : outputCfgs) {
> > > +		Stream &stream = streams_.emplace_back(this);
> > >  
> > > -	ret = m2m_->output()->setFormat(&format);
> > > -	if (ret < 0) {
> > > -		LOG(SimplePipeline, Error)
> > > -			<< "Failed to set input format: " << strerror(-ret);
> > > -		return ret;
> > > -	}
> > > +		if (!stream.isValid()) {
> > > +			LOG(SimplePipeline, Error) << "Failed to create stream";
> > > +			ret = -EINVAL;
> > > +			break;
> > > +		}
> > >  
> > > -	if (format.fourcc != videoFormat || format.size != inputCfg.size ||
> > > -	    format.planes[0].bpl != inputCfg.stride) {
> > > -		LOG(SimplePipeline, Error)
> > > -			<< "Input format not supported";
> > > -		return -EINVAL;
> > > +		ret = stream.configure(inputCfg, outputCfg);
> > > +		if (ret < 0)
> > > +			break;
> > >  	}
> > >  
> > > -	/* Set the pixel format and size on the output. */
> > > -	videoFormat = m2m_->capture()->toV4L2PixelFormat(outputCfg.pixelFormat);
> > > -	format = {};
> > > -	format.fourcc = videoFormat;
> > > -	format.size = outputCfg.size;
> > > -
> > > -	ret = m2m_->capture()->setFormat(&format);
> > >  	if (ret < 0) {
> > > -		LOG(SimplePipeline, Error)
> > > -			<< "Failed to set output format: " << strerror(-ret);
> > > +		streams_.clear();
> > >  		return ret;
> > >  	}
> > >  
> > > -	if (format.fourcc != videoFormat || format.size != outputCfg.size) {
> > > -		LOG(SimplePipeline, Error)
> > > -			<< "Output format not supported";
> > > -		return -EINVAL;
> > > -	}
> > > -
> > > -	inputBufferCount_ = inputCfg.bufferCount;
> > > -	outputBufferCount_ = outputCfg.bufferCount;
> > > -
> > >  	return 0;
> > >  }
> > >  
> > > -int SimpleConverter::exportBuffers(unsigned int count,
> > > +int SimpleConverter::exportBuffers(unsigned int output, unsigned int count,
> > >  				   std::vector<std::unique_ptr<FrameBuffer>> *buffers)
> > >  {
> > > -	return m2m_->capture()->exportBuffers(count, buffers);
> > > +	if (output >= streams_.size())
> > > +		return -EINVAL;
> > > +
> > > +	return streams_[output].exportBuffers(count, buffers);
> > >  }
> > >  
> > >  int SimpleConverter::start()
> > >  {
> > > -	int ret = m2m_->output()->importBuffers(inputBufferCount_);
> > > -	if (ret < 0)
> > > -		return ret;
> > > +	int ret;
> > >  
> > > -	ret = m2m_->capture()->importBuffers(outputBufferCount_);
> > > -	if (ret < 0) {
> > > -		stop();
> > > -		return ret;
> > > -	}
> > > -
> > > -	ret = m2m_->output()->streamOn();
> > > -	if (ret < 0) {
> > > -		stop();
> > > -		return ret;
> > > -	}
> > > -
> > > -	ret = m2m_->capture()->streamOn();
> > > -	if (ret < 0) {
> > > -		stop();
> > > -		return ret;
> > > +	for (Stream &stream : utils::reverse(streams_)) {
> > 
> > Do we have to start in reverse order?
> > I understand stopping them in the reverse order ... but starting?
> 
> Indeed, I'll fix that.

Ah, I was wondering about the reasoning for this. Now I see.

> > > +		ret = stream.start();
> > > +		if (ret < 0) {
> > > +			stop();
> > > +			return ret;
> > > +		}
> > >  	}
> > >  
> > >  	return 0;
> > > @@ -228,33 +339,48 @@ int SimpleConverter::start()
> > >  
> > >  void SimpleConverter::stop()
> > >  {
> > > -	m2m_->capture()->streamOff();
> > > -	m2m_->output()->streamOff();
> > > -	m2m_->capture()->releaseBuffers();
> > > -	m2m_->output()->releaseBuffers();
> > > +	for (Stream &stream : utils::reverse(streams_))
> > > +		stream.stop();
> > 
> > much nicer ;-)
> 
> I have to confess I really like how C++ makes this possible. The price
> to pay, of course, is total madness after studying templates.
> 
> > >  }
> > >  
> > > -int SimpleConverter::queueBuffers(FrameBuffer *input, FrameBuffer *output)
> > > +int SimpleConverter::queueBuffers(FrameBuffer *input,
> > > +				  const std::map<unsigned int, FrameBuffer *> &outputs)
> > >  {
> > > -	int ret = m2m_->output()->queueBuffer(input);
> > > -	if (ret < 0)
> > > -		return ret;
> > > +	unsigned int mask = 0;
> > > +	int ret;
> > >  
> > > -	ret = m2m_->capture()->queueBuffer(output);
> > > -	if (ret < 0)
> > > -		return ret;
> > > +	/* Validate the outputs as a sanity check. */
> > > +	if (outputs.empty())
> > > +		return -EINVAL;
> > > +
> > > +	for (auto [index, buffer] : outputs) {
> > > +		if (index >= streams_.size())
> > > +			return -EINVAL;
> > > +		if (mask & (1 << index))
> > 
> > I presume mask is checking to see/prevent there being multiple copies of
> > the same stream in outputs or something?
> > 
> > But this isn't very clear or readable - so a comment at least would help.
> 
> That's correct. I'll add a comment.

I thought it was fine, just that maybe mask could be named something
else. But I can't think of anything better, so maybe a comment would be
easier.

> > > +			return -EINVAL;
> > > +		if (!buffer)
> > > +			return -EINVAL;
> > > +
> > > +		mask |= 1 << index;
> > > +	}
> > > +
> > > +	/* Queue the input and output buffers to all the streams. */
> > > +	for (auto [index, buffer] : outputs) {
> > > +		ret = streams_[index].queueBuffers(input, buffer);
> > > +		if (ret < 0)
> > > +			return ret;
> > > +	}
> > > +
> > > +	/*
> > > +	 * Add the input buffer to the queue, with the number of streams as a
> > > +	 * reference count. Completion of the input buffer will be signalled by
> > > +	 * the stream that releases the last reference.
> > > +	 */
> > > +	queue_.emplace(std::piecewise_construct,
> > > +		       std::forward_as_tuple(input),
> > > +		       std::forward_as_tuple(outputs.size()));
> > >  
> > >  	return 0;
> > >  }
> > >  
> > > -void SimpleConverter::m2mInputBufferReady(FrameBuffer *buffer)
> > > -{
> > > -	inputBufferReady.emit(buffer);
> > > -}
> > > -
> > > -void SimpleConverter::m2mOutputBufferReady(FrameBuffer *buffer)
> > > -{
> > > -	outputBufferReady.emit(buffer);
> > > -}
> > > -
> > >  } /* namespace libcamera */
> > > diff --git a/src/libcamera/pipeline/simple/converter.h b/src/libcamera/pipeline/simple/converter.h
> > > index 739b24df0200..176978eefe48 100644
> > > --- a/src/libcamera/pipeline/simple/converter.h
> > > +++ b/src/libcamera/pipeline/simple/converter.h
> > > @@ -8,7 +8,10 @@
> > >  #ifndef __LIBCAMERA_PIPELINE_SIMPLE_CONVERTER_H__
> > >  #define __LIBCAMERA_PIPELINE_SIMPLE_CONVERTER_H__
> > >  
> > > +#include <functional>
> > > +#include <map>
> > >  #include <memory>
> > > +#include <string>
> > >  #include <tuple>
> > >  #include <vector>
> > >  
> > > @@ -37,26 +40,53 @@ public:
> > >  	strideAndFrameSize(const PixelFormat &pixelFormat, const Size &size);
> > >  
> > >  	int configure(const StreamConfiguration &inputCfg,
> > > -		      const StreamConfiguration &outputCfg);
> > > -	int exportBuffers(unsigned int count,
> > > +		      const std::vector<std::reference_wrapper<StreamConfiguration>> &outputCfg);
> > > +	int exportBuffers(unsigned int ouput, unsigned int count,
> > >  			  std::vector<std::unique_ptr<FrameBuffer>> *buffers);
> > >  
> > >  	int start();
> > >  	void stop();
> > >  
> > > -	int queueBuffers(FrameBuffer *input, FrameBuffer *output);
> > > +	int queueBuffers(FrameBuffer *input,
> > > +			 const std::map<unsigned int, FrameBuffer *> &outputs);
> > >  
> > >  	Signal<FrameBuffer *> inputBufferReady;
> > >  	Signal<FrameBuffer *> outputBufferReady;
> > >  
> > >  private:
> > > -	void m2mInputBufferReady(FrameBuffer *buffer);
> > > -	void m2mOutputBufferReady(FrameBuffer *buffer);
> > > +	class Stream
> > > +	{
> > > +	public:
> > > +		Stream(SimpleConverter *converter);
> > >  
> > > +		bool isValid() const { return m2m_ != nullptr; }
> > > +
> > > +		int configure(const StreamConfiguration &inputCfg,
> > > +			      const StreamConfiguration &outputCfg);
> > > +		int exportBuffers(unsigned int count,
> > > +				  std::vector<std::unique_ptr<FrameBuffer>> *buffers);
> > > +
> > > +		int start();
> > > +		void stop();
> > > +
> > > +		int queueBuffers(FrameBuffer *input, FrameBuffer *output);
> > > +
> > > +	private:
> > > +		void captureBufferReady(FrameBuffer *buffer);
> > > +		void outputBufferReady(FrameBuffer *buffer);
> > > +
> > > +		SimpleConverter *converter_;
> > > +		std::unique_ptr<V4L2M2MDevice> m2m_;
> > > +
> > > +		unsigned int inputBufferCount_;
> > > +		unsigned int outputBufferCount_;
> > > +	};
> > > +
> > > +	std::string deviceNode_;
> > >  	std::unique_ptr<V4L2M2MDevice> m2m_;
> > >  
> > > -	unsigned int inputBufferCount_;
> > > -	unsigned int outputBufferCount_;
> > > +	std::vector<Stream> streams_;
> > > +	std::map<FrameBuffer *, unsigned int> queue_;
> > >  };
> > >  
> > >  } /* namespace libcamera */
> > > diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
> > > index 7f9c57234256..b7a890ab772e 100644
> > > --- a/src/libcamera/pipeline/simple/simple.cpp
> > > +++ b/src/libcamera/pipeline/simple/simple.cpp
> > > @@ -610,7 +610,7 @@ int SimplePipelineHandler::configure(Camera *camera, CameraConfiguration *c)
> > >  		inputCfg.stride = captureFormat.planes[0].bpl;
> > >  		inputCfg.bufferCount = cfg.bufferCount;
> > >  
> > > -		ret = converter_->configure(inputCfg, cfg);
> > > +		ret = converter_->configure(inputCfg, { cfg });
> > >  		if (ret < 0) {
> > >  			LOG(SimplePipeline, Error)
> > >  				<< "Unable to configure converter";
> > > @@ -636,7 +636,7 @@ int SimplePipelineHandler::exportFrameBuffers(Camera *camera, Stream *stream,
> > >  	 * whether the converter is used or not.
> > >  	 */
> > >  	if (useConverter_)
> > > -		return converter_->exportBuffers(count, buffers);
> > > +		return converter_->exportBuffers(0, count, buffers);
> > 
> > I was wondering if it would be better to reference the Stream objects
> > rather than indexes, but I can see that might become confusing with our
> > Stream *stream we already have ...
> 
> I've thought about that, but it would require exposing the Stream class.
> If this was a public API I'd put more effort in the design :-)

Heh. I think indexes are fine. Due to the masking above I guess we're
limited to 31 streams?


Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>

> > And for now, we only have a single stream so index zero is enough for
> > now ...
> > 
> > Only a few trivial comments.
> > With those handled as you wish:
> > 
> > Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> > 
> > >  	else
> > >  		return data->video_->exportBuffers(count, buffers);
> > >  }
> > > @@ -917,7 +917,7 @@ void SimplePipelineHandler::bufferReady(FrameBuffer *buffer)
> > >  		FrameBuffer *output = converterQueue_.front();
> > >  		converterQueue_.pop();
> > >  
> > > -		converter_->queueBuffers(buffer, output);
> > > +		converter_->queueBuffers(buffer, { { 0, output } });
> > >  		return;
> > >  	}
> > >  
> 
> -- 
> Regards,
> 
> Laurent Pinchart
> _______________________________________________
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> libcamera-devel at lists.libcamera.org
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