Where does the preview delay mainly come from?

[zipswich]

The delay for resolution 4656x3496 is about 1000ms.
I took a look at do_preview void UVCPreview::do_preview(uvc_stream_ctrl_t *ctrl) in UVCPreview.cpp.

	for ( ; LIKELY(isRunning()) ; ) {
			frame_mjpeg = waitPreviewFrame();
			if (LIKELY(frame_mjpeg)) {
				//The following takes no time
				frame = get_frame(frame_mjpeg->width * frame_mjpeg->height * 2);
    			       //The following takes 150ms
    			       result = uvc_mjpeg2yuyv(frame_mjpeg, frame);   // MJPEG => yuyv
				//The following takes no time
				recycle_frame(frame_mjpeg);
				if (LIKELY(!result)) {
		                       //The following takes 200 ms for uvc_mjpeg2yuyv(frame_mjpeg, frame)
					frame = draw_preview_one(frame, &mPreviewWindow, uvc_any2rgbx, 4);
		                       //The entire process takes 350ms for uvc_mjpeg2yuyv(frame_mjpeg, frame)
					addCaptureFrame(frame);
				} else {
					recycle_frame(frame);
				}
			}
		}

Each iteration in the loop takes about 350ms, so the major part of the 1000ms delay is from somewhere else. Could anyone offer a tip on this?

[liu408309046]

Is there any solution? I have encountered a similar problem. When the resolution is set to a large one, the preview delay is very high

[shengjunhu]

Is there any solution? I have encountered a similar problem. When the resolution is set to a large one, the preview delay is very high

What is the maximum resolution you use ? Decoding is time-consuming during rendering.