[libcamera-devel] [PATCH] cam: Print timestamp of captured buffers

[Laurent Pinchart]

Hi Niklas,

On Mon, Aug 24, 2020 at 11:56:10PM +0200, Niklas Söderlund wrote:
> On 2020-08-22 16:35:42 +0300, Laurent Pinchart wrote:
> > Print the timestamp of the captured buffer in addition to the frame
> > rate, as this is more precise information that can help debugging issue.
> > While at it, compute the frame rate on the buffer timestamps instead of
> > sampling the clock in the request completion handler.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> 
> It would be nice to capture the before and after output of the tool in 
> the commit message. This is a nit so with and without it added,

I'll add

The log changes from

Using camera \_SB_.PCI0.XHC_.RHUB.HS05-5:1.0-0bda:58f4
Capture until user interrupts by SIGINT
fps: 0.00 stream0 seq: 000000 bytesused: 169968
fps: 28.57 stream0 seq: 000002 bytesused: 170352
fps: 31.25 stream0 seq: 000003 bytesused: 170428
fps: 32.26 stream0 seq: 000004 bytesused: 170672
fps: 27.78 stream0 seq: 000005 bytesused: 170568

to

Using camera \_SB_.PCI0.XHC_.RHUB.HS05-5:1.0-0bda:58f4
Capture until user interrupts by SIGINT
93473.942525 (0.00 fps) stream0 seq: 000000 bytesused: 183940
93474.006528 (15.62 fps) stream0 seq: 000002 bytesused: 183512
93474.038525 (31.25 fps) stream0 seq: 000003 bytesused: 183760
93474.074530 (27.77 fps) stream0 seq: 000004 bytesused: 182704
93474.106581 (31.20 fps) stream0 seq: 000005 bytesused: 182768

> Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> 
> > ---
> >  src/cam/capture.cpp | 18 +++++++++++-------
> >  src/cam/capture.h   |  4 ++--
> >  2 files changed, 13 insertions(+), 9 deletions(-)
> > 
> > diff --git a/src/cam/capture.cpp b/src/cam/capture.cpp
> > index af9029b743de..5510c009ca57 100644
> > --- a/src/cam/capture.cpp
> > +++ b/src/cam/capture.cpp
> > @@ -5,7 +5,6 @@
> >   * capture.cpp - Cam capture
> >   */
> >  
> > -#include <chrono>
> >  #include <iomanip>
> >  #include <iostream>
> >  #include <limits.h>
> > @@ -159,14 +158,19 @@ void Capture::requestComplete(Request *request)
> >  
> >  	const Request::BufferMap &buffers = request->buffers();
> >  
> > -	std::chrono::steady_clock::time_point now = std::chrono::steady_clock::now();
> > -	double fps = std::chrono::duration_cast<std::chrono::milliseconds>(now - last_).count();
> > -	fps = last_ != std::chrono::steady_clock::time_point() && fps
> > -	    ? 1000.0 / fps : 0.0;
> > -	last_ = now;
> > +	/*
> > +	 * Compute the frame rate. The timestamp is arbitrarily retrieved from
> > +	 * the first buffer, as all buffers should have matching timestamps.
> > +	 */
> > +	uint64_t ts = buffers.begin()->second->metadata().timestamp;
> > +	double fps = ts - last_;
> > +	fps = last_ != 0 && fps ? 1000000000.0 / fps : 0.0;
> > +	last_ = ts;
> >  
> >  	std::stringstream info;
> > -	info << "fps: " << std::fixed << std::setprecision(2) << fps;
> > +	info << ts / 1000000000 << "."
> > +	     << std::setw(6) << std::setfill('0') << ts / 1000 % 1000000
> > +	     << " (" << std::fixed << std::setprecision(2) << fps << " fps)";
> >  
> >  	for (auto it = buffers.begin(); it != buffers.end(); ++it) {
> >  		const Stream *stream = it->first;
> > diff --git a/src/cam/capture.h b/src/cam/capture.h
> > index b4e39d51fdfa..0aebdac944cf 100644
> > --- a/src/cam/capture.h
> > +++ b/src/cam/capture.h
> > @@ -7,8 +7,8 @@
> >  #ifndef __CAM_CAPTURE_H__
> >  #define __CAM_CAPTURE_H__
> >  
> > -#include <chrono>
> >  #include <memory>
> > +#include <stdint.h>
> >  
> >  #include <libcamera/buffer.h>
> >  #include <libcamera/camera.h>
> > @@ -38,7 +38,7 @@ private:
> >  
> >  	std::map<const libcamera::Stream *, std::string> streamName_;
> >  	BufferWriter *writer_;
> > -	std::chrono::steady_clock::time_point last_;
> > +	uint64_t last_;
> >  
> >  	EventLoop *loop_;
> >  	unsigned int captureCount_;

-- 
Regards,

Laurent Pinchart