Changing format of VideoInput

[Zjaun]

Attempting to change the format of the FrameGrabber, as it defaults to YUV2. Cheap capture cards do not usually support YUV2 at Full HD resolutions, so MJPEG is the way to go. However, the setFormat() method doesn't seem to do anything. Here is my attempt at doing so:

FrameGrabber grabber = new VideoInputFrameGrabber(8);
try {
    grabber.setFormat("mjpg"); // not sure if mjpg or MJPG, neither works
    grabber.start();
    // do something with the grabber
    grabber.close();
} catch (FrameGrabber.Exception e) {
    System.out.println(e);
}

I attempted to set the grabber's resolution outside the range of the supported ones, and I can clearly see that there are different formats:

SETUP: trying format RGB24 @ 1366 by 768
SETUP: trying format RGB32 @ 1366 by 768
SETUP: trying format RGB555 @ 1366 by 768
SETUP: trying format RGB565 @ 1366 by 768
SETUP: trying format YUY2 @ 1366 by 768
SETUP: trying format YVYU @ 1366 by 768
SETUP: trying format YUYV @ 1366 by 768
SETUP: trying format IYUV @ 1366 by 768
SETUP: trying format UYVY @ 1366 by 768
SETUP: trying format YV12 @ 1366 by 768
SETUP: trying format YVU9 @ 1366 by 768
SETUP: trying format Y411 @ 1366 by 768
SETUP: trying format Y41P @ 1366 by 768
SETUP: trying format Y211 @ 1366 by 768
SETUP: trying format AYUV @ 1366 by 768
SETUP: trying format Y800 @ 1366 by 768
SETUP: trying format Y8 @ 1366 by 768
SETUP: trying format GREY @ 1366 by 768
SETUP: trying format MJPG @ 1366 by 768
SETUP: trying format H264 @ 1366 by 768

I have seen a GitHub post regarding this, but it eventually swayed away to using the OpenCV implementation. Is there anyway to change the format of the VideoInput? Thanks!

[saudet]

I'm sure videoInput has a setting for that somewhere, we'd just need to add it in here somewhere:
https://github.com/bytedeco/javacv/blob/master/src/main/java/org/bytedeco/javacv/VideoInputFrameGrabber.java

[Zjaun]

Just learned about the videoInput class in this library. I can now set the format (or media type) by using the setRequestedMediaSubType() method. How can I grab frames from videoInput then? This is my attempt at doing so:

videoInput vi = new videoInput();
vi.setRequestedMediaSubType(18); // mjpeg
vi.setupDevice(8, 1920, 1080);
FrameGrabber grabber = new VideoInputFrameGrabber(8); // invalid, since device 8 is already in use by vi

[Zjaun]

Okay I have found a solution for this. I created a custom VideoInputFrameGrabber class that checks if the parameter of setFormat() is formats (VI_NTSC_M, VI_PAL_B, etc) or media subtypes (RGB24, RGB32, RGB555, etc.). I also think that the FrameGrabber class has to be modified as well, since the setFormat() method returns a boolean, whereas the setRequestedMediaSubType() method does not. That must return a boolean so that the custom VideoInputFrameGrabber class that I modified also throws an exception.

This is how I implemented my solution (if you have a better solution, please comment it here!)

public void start(int connection) throws Exception {
        myVideoInput = new videoInput();
        if (format != null && format.length() > 0) {
            String formats[] = {"PAL_B", "PAL_D", "PAL_G", "PAL_H", "PAL_I", "PAL_M", "PAL_N", "PAL_NC", 
                                "SECAM_B", "SECAM_D", "SECAM_G", "SECAM_H", "SECAM_K", "SECAM_K1", "SECAM_L",
                                "NTSC_M", "NTSC_M_J", "NTSC_433", };
            String subTypes[] = {"RGB24", "RGB32", "RGB555", "RGB565", "YUY2", "YVYU", "YUYV", "IYUV", "UYVY", 
                                 "YV12", "YVU9", "Y411", "Y41P", "Y211", "AYUV", "Y800", "Y8", "GREY", "MJPG"};
            boolean settingFormat = Arrays.asList(formats).contains(format);
            boolean settingSubType = Arrays.asList(subTypes).contains(format);
            if (settingFormat) {
                int f = format.equals("NTSC_M")   ? VI_NTSC_M   :
                        format.equals("PAL_B")    ? VI_PAL_B    :
                        format.equals("PAL_D")    ? VI_PAL_D    :
                        format.equals("PAL_G")    ? VI_PAL_G    :
                        format.equals("PAL_H")    ? VI_PAL_H    :
                        format.equals("PAL_I")    ? VI_PAL_I    :
                        format.equals("PAL_M")    ? VI_PAL_M    :
                        format.equals("PAL_N")    ? VI_PAL_N    :
                        format.equals("PAL_NC")   ? VI_PAL_NC   :
                        format.equals("SECAM_B")  ? VI_SECAM_B  :
                        format.equals("SECAM_D")  ? VI_SECAM_D  :
                        format.equals("SECAM_G")  ? VI_SECAM_G  :
                        format.equals("SECAM_H")  ? VI_SECAM_H  :
                        format.equals("SECAM_K")  ? VI_SECAM_K  :
                        format.equals("SECAM_K1") ? VI_SECAM_K1 :
                        format.equals("SECAM_L")  ? VI_SECAM_L  :
                        format.equals("NTSC_M_J") ? VI_NTSC_M_J :
                        format.equals("NTSC_433") ? VI_NTSC_433 : -1;
                myVideoInput.setFormat(deviceNumber, f);
                if (f >= 0 && !myVideoInput.setFormat(deviceNumber, f)) {
                    throw new Exception("videoInput.setFormat() Error: Could not set format " + format + ".");
                }
            } else if (settingSubType) {
                int s = format.equals("RGB24")  ? VI_MEDIASUBTYPE_RGB24  :
                        format.equals("RGB32")  ? VI_MEDIASUBTYPE_RGB32  :
                        format.equals("RGB555") ? VI_MEDIASUBTYPE_RGB555 :
                        format.equals("YUY2")   ? VI_MEDIASUBTYPE_YUY2   :
                        format.equals("YVYU")   ? VI_MEDIASUBTYPE_YVYU   :
                        format.equals("YUYV")   ? VI_MEDIASUBTYPE_YUYV   :
                        format.equals("IYUV")   ? VI_MEDIASUBTYPE_IYUV   :
                        format.equals("UYVY")   ? VI_MEDIASUBTYPE_UYVY   :
                        format.equals("YV12")   ? VI_MEDIASUBTYPE_YV12   :
                        format.equals("YVU9")   ? VI_MEDIASUBTYPE_YVU9   :
                        format.equals("Y411")   ? VI_MEDIASUBTYPE_Y411   :
                        format.equals("Y41P")   ? VI_MEDIASUBTYPE_Y41P   :
                        format.equals("Y211")   ? VI_MEDIASUBTYPE_Y211   :
                        format.equals("AYUV")   ? VI_MEDIASUBTYPE_AYUV   :
                        format.equals("Y800")   ? VI_MEDIASUBTYPE_Y800   :
                        format.equals("Y8")     ? VI_MEDIASUBTYPE_Y8     :
                        format.equals("GREY")   ? VI_MEDIASUBTYPE_GREY   :
                        format.equals("MJPG")   ? VI_MEDIASUBTYPE_MJPG   : -1;
                myVideoInput.setRequestedMediaSubType(s);
            }
            if (frameRate > 0) {
                myVideoInput.setIdealFramerate(deviceNumber, (int)frameRate);
            }
            if (!myVideoInput.setupDevice(deviceNumber, imageWidth  > 0 ? imageWidth  : 640,
                                                        imageHeight > 0 ? imageHeight : 480, connection)) {
                myVideoInput = null;
                throw new Exception("videoInput.setupDevice() Error: Could not setup device.");
            }   
        }
    }

[saudet]

Looks good! Please open a pull request

[saudet]

See pull #2107