techyian
commented
5 years ago Hi, thanks for raising the issue here, it means I can post more in a comment compared to Twitter.
You can keep your capture handler as you currently have it. However instead of calculating your timediffs in there, you can move the timediff code to a callback handler - in your case, you'll be wanting to use the FastImageOutputCallbackHandler class.
As described in this gist, you can see I calculate the timediffs in the following block of code:
if (eos)
{
if (DateTime.Now - _start > TimeSpan.FromSeconds(1))
{
MMALLog.Logger.Info($"FPS: {_fps}");
_fps = 0;
_start = DateTime.Now;
}
_fps++;
// In rapid capture mode, provide the ability to do post-processing once we have a complete frame.
this.WorkingPort.Handler?.PostProcess();
}There is a DateTime at the top of the class called _start and an int called _fps.
The reason I say the callback handler is a better place to calculate is because you have raw access to the buffer header object, and that will tell you whether the piece of data you're currently dealing with is the end of the file. We only want to increase the fps value if we're dealing with the end of a frame and the eos boolean will be true if the data is the end of the image frame.
As an example piece of code, this is what I'm currently using to test this functionality and it's returning between 10-11fps:
MMALCameraConfig.SensorMode = MMALSensorMode.Mode5;
MMALCameraConfig.VideoFramerate = new MMAL_RATIONAL_T(10, 1);
MMALCameraConfig.VideoResolution = new Resolution(810, 648);
using (var splitter = new MMALSplitterComponent(null))
using (var imgEncoder = new MMALImageEncoder(null, continuousCapture: true))
using (var nullSink = new MMALNullSinkComponent())
{
cam.ConfigureCameraSettings();
// Create our component pipeline.
imgEncoder.ConfigureOutputPort(0, MMALEncoding.JPEG, MMALEncoding.I420, 90);
cam.Camera.VideoPort.ConnectTo(splitter);
splitter.Outputs[0].ConnectTo(imgEncoder);
cam.Camera.PreviewPort.ConnectTo(nullSink);
// Camera warm up time
await Task.Delay(2000);
await cam.ProcessAsync(cam.Camera.VideoPort);
} I haven't used any capture handlers in this example as I'm not interested in saving the image frames, I just want to demonstrate the FPS calculation.
Does this make sense?
dommy1C
Using the inMemeoryHandler to deal with images in byte array and bypassing the automatically saving to disc routine I have this:
}
I find this works well.
However, I wish to throttle the fps to 10 frames per second. I am sure I can make sure I only pass 10 frames a second to my subscriber by comparing timediffs etc but what I was hoping to achieve was forcing the camera to only take 10 frames per second. Is this achievable?