Develop Reference

How to change rtsp streaming size in c#?

I am using rtsp streaming in c# using below code
However, the code below plays back the original size of the video.
I want to resize the video
How can I increase the size of my video?
video = new VideoCapture();
video.Open(rtspUrl);
using (Mat image = new Mat())
{
while (true)
{
if (!video.Read(image))
{
Cv2.WaitKey();
}
if (!image.Empty())
{
Bitmap bmp = OpenCvSharp.Extensions.BitmapConverter.ToBitmap(image);
pbStream.Image = bmp;
}
if (Cv2.WaitKey(1) >= 0)
break;
if (isRun == false)
{
break;
}
}
}
video = null;

Accord.Video.FFMPEG getting error for long video

I use Accord.Video.FFMPEG to extract images every 10 frames from a video. Total frames for this video is 38194 frames. First run is good, I can save image every 10 frames but after run of about 38185 frames i got null return from this code Bitmap bmpBaseOriginal = vReader.ReadVideoFrame();, if I see in the video there is no problem at the end of video.
I do something like this
using (var vReader = new VideoFileReader())
{
vReader.Open(files[0]);
TotalFrame = vReader.FrameCount;
countin = Convert.ToInt32(TotalFrame / Convert.ToDouble(countAsset));
Fps = vReader.FrameRate.Value;
int a = 0;
for (int i = 0; i < vReader.FrameCount; i++)
{
if(i < vReader.FrameCount - 1)
{
Bitmap bmpBaseOriginal = vReader.ReadVideoFrame();
if (i%10 == 0)
{
a++;
bmpBaseOriginal.Save(string.Format("{0}\\{1}.jpeg", dirVideo.FullName, a), ImageFormat.Jpeg);
}
bmpBaseOriginal.Dispose();
}
else
{
a++;
Bitmap bmpBaseOriginal = vReader.ReadVideoFrame();
bmpBaseOriginal.Save(string.Format("{0}\\{1}.jpeg", dirVideo.FullName, a), ImageFormat.Jpeg);
bmpBaseOriginal.Dispose();
}
}
vReader.Close();
}
this problem occurs again on another video if the video has a lot of frames, but no problem if the video has a less frames.
How to solve it?

How to extract rotated images from PDF with iText

I need to extract images from PDF.
I know that some images are rotated 90 degrees (I checked with online tools).
I'm using this code:
PdfRenderListener:
public class PdfRenderListener : IExtRenderListener
{
// other methods ...
public void RenderImage(ImageRenderInfo renderInfo)
{
try
{
var mtx = renderInfo.GetImageCTM();
var image = renderInfo.GetImage();
var fillColor = renderInfo.GetCurrentFillColor();
var color = Color.FromArgb(fillColor?.RGB ?? Color.Empty.ToArgb());
var fileType = image.GetFileType();
var extension = "." + fileType;
var bytes = image.GetImageAsBytes();
var height = mtx[Matrix.I22];
var width = mtx[Matrix.I11];
// rotated image
if (height == 0 && width == 0)
{
var h = Math.Abs(mtx[Matrix.I12]);
var w = Math.Abs(mtx[Matrix.I21]);
}
// save image
}
catch (Exception e)
{
Console.WriteLine(e);
}
}
}
When I save images with this code the rotated images are saved with distortion.
I have read this post iText 7 ImageRenderInfo Matrix contains negative height on Even number Pages and mkl answer.
In current transfromation matrix (mtx) I have these values:
0
841.9
0
-595.1
0
0
595.1
0
1
I know image rotated 90 degrees. How can I transform an image to get a normal image?

As #mkl mentioned, the true reason was not in the rotation of the image, but with the applied filter.
I analyzed the pdf file with iText RUPS and found that the image was encoded with a CCITTFaxDecode filter:
RUPS screen
Next, I looked for ways to decode this filter and found these questions
Extracting image from PDF with /CCITTFaxDecode filter.
How to use Bit Miracle LibTiff.Net to write the image to a MemoryStream
I used the BitMiracle.LibTiff.NET library
I wrote this method:
private byte[] DecodeInternal(byte[] rawBytes, int width, int height, int k, int bitsPerComponent)
{
var compression = GetCompression(k);
using var ms = new MemoryStream();
var tms = new TiffStream();
using var tiff = Tiff.ClientOpen("in-memory", "w", ms, tms);
tiff.SetField(TiffTag.IMAGEWIDTH, width);
tiff.SetField(TiffTag.IMAGELENGTH, height);
tiff.SetField(TiffTag.COMPRESSION, compression);
tiff.SetField(TiffTag.BITSPERSAMPLE, bitsPerComponent);
tiff.SetField(TiffTag.SAMPLESPERPIXEL, 1);
var writeResult = tiff.WriteRawStrip(0, rawBytes, rawBytes.Length);
if (writeResult == -1)
{
Console.WriteLine("Decoding error");
}
tiff.CheckpointDirectory();
var decodedBytes = ms.ToArray();
tiff.Close();
return decodedBytes;
}
private Compression GetCompression(int k)
{
return k switch
{
< 0 => Compression.CCITTFAX4,
0 => Compression.CCITTFAX3,
_ => throw new NotImplementedException("K > 0"),
};
}
After decoding and rotating the image, I was able to save a normal image. Thanks everyone for the help.

You can try this. I'm using Itext 7 for java. Here you still need to write your own listener:
public class MyImageRenderListener implements IEventListener {
protected String path;
protected String extension;
public MyImageRenderListener (String path) {
this.path = path;
}
public void eventOccurred(IEventData data, EventType type) {
switch (type) {
case RENDER_IMAGE:
try {
String filename;
FileOutputStream os;
ImageRenderInfo renderInfo = (ImageRenderInfo) data;
PdfImageXObject image = renderInfo.getImage();
if (image == null) {
return;
}
byte[] imageByte = image.getImageBytes(true);
extension = image.identifyImageFileExtension();
filename = String.format(path, image.getPdfObject().getIndirectReference().getObjNumber(), extension);
os = new FileOutputStream(filename);
os.write(imageByte);
os.flush();
os.close();
} catch (com.itextpdf.io.exceptions.IOException | IOException e) {
System.out.println(e.getMessage());
}
break;
default:
break;
}
}
public Set<EventType> getSupportedEvents() {
return null;
}
}
I checked for a pdf with a random rotation angle, and 90 degrees, the resulting picture was obtained without distortion
public void manipulatePdf() throws IOException, SQLException, ParserConfigurationException, SAXException {
PdfDocument pdfDoc = new PdfDocument(new PdfReader("path to pdf"), new PdfWriter(new ByteArrayOutputStream()));
MyImageRenderListener listener = new MyImageRenderListener("path to resulting image");
PdfCanvasProcessor parser = new PdfCanvasProcessor(listener);
for (int i = 1; i <= pdfDoc.getNumberOfPages(); i++) {
parser.processPageContent(pdfDoc.getPage(i));
}
pdfDoc.close();
}

ARCore for Unity save camera image

Using ARCore for Unity, trying to save Frame.CameraImage.AcquireCameraImageBytes() as image and scanning the image for QR code. But the converted image is not in actual scale and it is repeating, so not able to deduct the QR code correctly.
Here is my code
void Update()
{
using (var image = Frame.CameraImage.AcquireCameraImageBytes())
{
if (image.IsAvailable)
{
byte[] m_EdgeImage = null;
Color32[] pixels = null;
IParser Parser = new ZXingParser();
if (_texture == null || m_EdgeImage == null || _texture.width != image.Width || _texture.height != image.Height)
{
_texture = new Texture2D(image.Width, image.Height, TextureFormat.RGBA32, false, false);
m_EdgeImage = new byte[image.Width * image.Height*4];
}
System.Runtime.InteropServices.Marshal.Copy(image.Y, m_EdgeImage, 0, image.Width * image.Height);
_texture.LoadRawTextureData(m_EdgeImage);
_texture.Apply();
ParserResult Result = Parser.Decode(pixels, _texture.width, _texture.height);
if (Result != null)
{
Debug.Log("QRCODE");
}
else
{
var encodedJpg = _texture.EncodeToJPG();
var path = Application.persistentDataPath;
File.WriteAllBytes(path + "/test.jpg", encodedJpg);
Debug.Log("NOQRCODE");
Application.Quit();
}
}
}
}
Here is the converted image
What is wrong here

An ARCore camera image with its data accessible from the CPU in YUV-420-888 formatCheck this. The buffer size is width*height*1.5 for YUV. You may need to convert YUV to RGB format.

Image doesn't update when written to.. weird goings on

I have a Kinect WPF Application that takes images from the Kinect, does some feature detection using EmguCV (A C# opencv wrapper) and displays the output on the using a WPF image.
I have had this working before, but the application now refuses to update the screen image when the imagesource is written to, but I have not changed the way it works.
the Image(called video) is written to as such:
video.Source = bitmapsource;
in the colorframeready event handler.
This works fine until I introduce some opencv code before the imagesource is written to. It does not matter what source is used, so I don't think it is a conflict there. I have narrowed down the offending EmguCV code to this line:
RecentKeyPoints = surfCPU.DetectKeyPointsRaw(ImageRecent, null);
which jumps straight into the opencv code. It is worth noting that:
ImageRecent has completely different origins to the bitmapsource updating the screen.
Reading video.Source returns the bitmapsource, so it seems to be writing correctly, just not updating the screen.
Let me know if you want any more information...
void nui_ColorFrameReady(object sender, ColorImageFrameReadyEventArgs e)
{
// Checks for a recent Depth Image
if (!TrackingReady) return;
// Stores image
using (ColorImageFrame colorImageFrame = e.OpenColorImageFrame())
{
if (colorImageFrame != null)
{
if (FeatureTracker.ColourImageRecent == null)
//allocate the first time
FeatureTracker.ColourImageRecent = new byte[colorImageFrame.PixelDataLength];
colorImageFrame.CopyPixelDataTo(FeatureTracker.ColourImageRecent);
}
else return;
}
FeatureTracker.FeatureDetect(nui);
//video.Source = FeatureTracker.ColourImageRecent.ToBitmapSource();
video.Source = ((Bitmap)Bitmap.FromFile("test1.png")).ToBitmapSource();
TrackingReady = false;
}
public Bitmap FeatureDetect(KinectSensor nui)
{
byte[] ColourClone = new byte[ColourImageRecent.Length];
Array.Copy(ColourImageRecent, ColourClone, ColourImageRecent.Length);
Bitmap test = (Bitmap)Bitmap.FromFile("test1.png");
test.RotateFlip(RotateFlipType.RotateNoneFlipY);
Image<Gray, Byte> ImageRecent = new Image<Gray, byte>(test);
SURFDetector surfCPU = new SURFDetector(2000, false);
VectorOfKeyPoint RecentKeyPoints;
Matrix<int> indices;
Matrix<float> dist;
Matrix<byte> mask;
bool MatchFailed = false;
// extract SURF features from the object image
RecentKeyPoints = surfCPU.DetectKeyPointsRaw(ImageRecent, null);
//Matrix<float> RecentDescriptors = surfCPU.ComputeDescriptorsRaw(ImageRecent, null, RecentKeyPoints);
//MKeyPoint[] RecentPoints = RecentKeyPoints.ToArray();
// don't feature detect on first attempt, just store image details for next attempt
#region
/*
if (KeyPointsOld == null)
{
KeyPointsOld = RecentKeyPoints;
PointsOld = RecentPoints;
DescriptorsOld = RecentDescriptors;
return ImageRecent.ToBitmap();
}
*/
#endregion
// Attempt to match points to their nearest neighbour
#region
/*
BruteForceMatcher SURFmatcher = new BruteForceMatcher(BruteForceMatcher.DistanceType.L2F32);
SURFmatcher.Add(RecentDescriptors);
int k = 5;
indices = new Matrix<int>(DescriptorsOld.Rows, k);
dist = new Matrix<float>(DescriptorsOld.Rows, k);
*/
// Match features, provide the top k matches
//SURFmatcher.KnnMatch(DescriptorsOld, indices, dist, k, null);
// Create mask and set to allow all features
//mask = new Matrix<byte>(dist.Rows, 1);
//mask.SetValue(255);
#endregion
//Features2DTracker.VoteForUniqueness(dist, 0.8, mask);
// Check number of good maches and for error and end matching if true
#region
//int nonZeroCount = CvInvoke.cvCountNonZero(mask);
//if (nonZeroCount < 5) MatchFailed = true;
/*
try
{
nonZeroCount = Features2DTracker.VoteForSizeAndOrientation(RecentKeyPoints, KeyPointsOld, indices, mask, 1.5, 20);
}
catch (SystemException)
{
MatchFailed = true;
}
if (nonZeroCount < 5) MatchFailed = true;
if (MatchFailed)
{
return ImageRecent.ToBitmap();
}
*/
#endregion
//DepthMapColourCoordsRecent = CreateDepthMap(nui, DepthImageRecent);
//PointDist[] FeatureDistances = DistanceToFeature(indices, mask, RecentPoints);
//Image<Rgb,Byte> rgbimage = ImageRecent.Convert<Rgb, Byte>();
//rgbimage = DrawPoints(FeatureDistances, rgbimage);
// Store recent image data for next feature detect.
//KeyPointsOld = RecentKeyPoints;
//PointsOld = RecentPoints;
//DescriptorsOld = RecentDescriptors;
//CreateDepthMap(nui, iva);
//rgbimage = CreateDepthImage(DepthMapColourCoordsRecent, rgbimage);
// Convert image back to a bitmap
count++;
//Bitmap bitmap3 = rgbimage.ToBitmap();
//bitmapstore = bitmap3;
//bitmap3.Save("test" + count.ToString() + ".png");
return null;
}

This is a little late, but I had a similar problem and thought I'd share my solution.
In my case I was processing the depth stream. The default resolution was 640x480, and Emgu just wasn't able to process the image fast enough to keep up with the frameready handler. As soon as I reduced the depth stream resolution to 320x240 the problem went away.
I also went a bit further and moved my image processing to a different thread which sped it up even more (do a search for ComponentDispatcher.ThreadIdle). I'm still not able to do 640x480 at a reasonable frame rate, but at least the image renders so I can see what's going on.