[libcamera-devel] [PATCH v3 3/3] cam: Add optional argument to --capture to specify how many frames to capture

[Niklas Söderlund]

Hi Umang,

Thanks for your comment.

On 2020-07-28 16:07:56 +0000, Umang Jain wrote:
> Hi Niklas,
> 
> Thanks for extending --capture to capture a certain no. of frames.
> It super handy to use.
> 
> Just want to let you know, it does not work if I use short-hand "-C=10".
> However, cam -c 1 --capture=10 seems to work just fine.
> 
> On $cam -c 1 -C=10 O get the following:
> 
> [uajain at localhost libcamera]$ sudo ./build/src/cam/cam  -c 1 -C=10
> Can't parse integer argument for option --capture
> Options:
> ...

That is because for optional arguments to short options the = character 
is dropped :-)

    $ cam -c 1 -C10
    Using camera Logitech Webcam C930e
    Capture 10 frames
    fps: 0.00 stream0 seq: 000000 bytesused: 49517
    fps: 37.04 stream0 seq: 000001 bytesused: 50679
    fps: 8.13 stream0 seq: 000002 bytesused: 49837
    fps: 8.13 stream0 seq: 000003 bytesused: 50275
    fps: 7.87 stream0 seq: 000004 bytesused: 50851
    fps: 8.13 stream0 seq: 000005 bytesused: 51369
    fps: 8.06 stream0 seq: 000006 bytesused: 50756
    fps: 14.93 stream0 seq: 000007 bytesused: 51042
    fps: 15.62 stream0 seq: 000008 bytesused: 52641
    fps: 14.93 stream0 seq: 000009 bytesused: 51621

> 
> On 7/25/20 12:48 AM, Niklas Söderlund wrote:
> > Extend the '--capture' option with and optional numerical argument to be
> > able to specify how many frames to capture before exiting. If the
> > optional argument is not provided the old behavior of running until the
> > user interrupts with a SIGINT is retained.
> > 
> > Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> > Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> > * Changes since v2
> > - Move check in Capture::requestComplete() as to not leak the created
> >    but never used Request.
> > * Changes since v1
> > - Extend --capture option instead of adding a new --count option.
> > ---
> >   src/cam/capture.cpp | 18 ++++++++++++++++--
> >   src/cam/capture.h   |  2 ++
> >   src/cam/main.cpp    |  5 +++--
> >   3 files changed, 21 insertions(+), 4 deletions(-)
> > 
> > diff --git a/src/cam/capture.cpp b/src/cam/capture.cpp
> > index f811a18c579508a1..3d8e89d52c7ab68d 100644
> > --- a/src/cam/capture.cpp
> > +++ b/src/cam/capture.cpp
> > @@ -18,7 +18,8 @@ using namespace libcamera;
> >   Capture::Capture(std::shared_ptr<Camera> camera, CameraConfiguration *config,
> >   		 EventLoop *loop)
> > -	: camera_(camera), config_(config), writer_(nullptr), loop_(loop)
> > +	: camera_(camera), config_(config), writer_(nullptr), loop_(loop),
> > +	  captureCount_(0), captureLimit_(0)
> >   {
> >   }
> > @@ -26,6 +27,9 @@ int Capture::run(const OptionsParser::Options &options)
> >   {
> >   	int ret;
> > +	captureCount_ = 0;
> > +	captureLimit_ = options[OptCapture].toInteger();
> > +
> >   	if (!camera_) {
> >   		std::cout << "Can't capture without a camera" << std::endl;
> >   		return -ENODEV;
> > @@ -132,7 +136,11 @@ int Capture::capture(FrameBufferAllocator *allocator)
> >   		}
> >   	}
> > -	std::cout << "Capture until user interrupts by SIGINT" << std::endl;
> > +	if (captureLimit_)
> > +		std::cout << "Capture " << captureLimit_ << " frames" << std::endl;
> > +	else
> > +		std::cout << "Capture until user interrupts by SIGINT" << std::endl;
> > +
> >   	ret = loop_->exec();
> >   	if (ret)
> >   		std::cout << "Failed to run capture loop" << std::endl;
> > @@ -184,6 +192,12 @@ void Capture::requestComplete(Request *request)
> >   	std::cout << info.str() << std::endl;
> > +	captureCount_++;
> > +	if (captureLimit_ && captureCount_ >= captureLimit_) {
> > +		loop_->exit(0);
> > +		return;
> > +	}
> > +
> >   	/*
> >   	 * Create a new request and populate it with one buffer for each
> >   	 * stream.
> > diff --git a/src/cam/capture.h b/src/cam/capture.h
> > index acdefc47b24314d2..32940a2a12138887 100644
> > --- a/src/cam/capture.h
> > +++ b/src/cam/capture.h
> > @@ -41,6 +41,8 @@ private:
> >   	std::chrono::steady_clock::time_point last_;
> >   	EventLoop *loop_;
> > +	unsigned int captureCount_;
> > +	unsigned int captureLimit_;
> >   };
> >   #endif /* __CAM_CAPTURE_H__ */
> > diff --git a/src/cam/main.cpp b/src/cam/main.cpp
> > index 3e83feabe64e036c..f5aba041d7c4c181 100644
> > --- a/src/cam/main.cpp
> > +++ b/src/cam/main.cpp
> > @@ -167,8 +167,9 @@ int CamApp::parseOptions(int argc, char *argv[])
> >   	parser.addOption(OptCamera, OptionString,
> >   			 "Specify which camera to operate on, by name or by index", "camera",
> >   			 ArgumentRequired, "camera");
> > -	parser.addOption(OptCapture, OptionNone,
> > -			 "Capture until interrupted by user", "capture");
> > +	parser.addOption(OptCapture, OptionInteger,
> > +			 "Capture until interrupted by user or until <count> frames captured",
> > +			 "capture", ArgumentOptional, "count");
> >   	parser.addOption(OptFile, OptionString,
> >   			 "Write captured frames to disk\n"
> >   			 "The first '#' character in the file name is expanded to the stream name and frame sequence number.\n"

-- 
Regards,
Niklas Söderlund