QImage to QVideoFrame Conversion access violation issue

[iSolve_Tech]

QVideoFrameFormat format(image.size(), QVideoFrameFormat::pixelFormatFromImageFormat(image.format()));
QVideoFrame frame(format);
if (!frame.isValid()) {
qDebug() << "Error: Invalid video frame format";
// Handle error
} else {
if (!frame.map(QVideoFrame::ReadWrite)) {
qDebug() << "Error: Failed to map video frame";
// Handle error
} else {
// Check if mapping succeeded
qDebug() << "Video frame mapped successfully";

          // Perform memcpy for each plane
          const int planeCount = frame.planeCount();
          for (int plane = 0; plane < planeCount; ++plane) {
              uchar* frameBits = frame.bits(plane);
              uchar* imgBits = image.bits();
              const int planeBytes = frame.mappedBytes(plane);

              // Check if sizes match for this plane
              if (frameBits && imgBits && planeBytes >= 0) {
                  memcpy(frameBits, imgBits, planeBytes);
                  qDebug() << "Memcpy for plane" << plane << "completed successfully";
              } else {
                  qDebug() << "Error: Invalid pointer(s) or plane size";
                  // Handle error
              }
          }

          // Unmap the frame after memcpy
          frame.unmap();
      }
  }

This is my code for the conversion from QImage to QVideoFrame but am facing access violation issue due to this(memcpy(frameBits, imgBits, planeBytes)) I think so. How can I solve this issue?

[jsulm]

@iSolve_Tech said in QImage to QVideoFrame Conversion access violation issue:

I think so.

You think so or did you run in debugger to validate this assumption?
How does stack trace look like after the crash?

[iSolve_Tech]

@jsulm when executing image.bits() am getting Streaming Thread (10): EXC_BAD_ACCESS (code=1, address=0x127e98000)

[jsulm]

@iSolve_Tech Then check what you pass to memcpy: are both dest/src pointers valid? Is dest pointing to a memory chunk same size or bigger than src?

[Bonnie]

@iSolve_Tech
Some minor points:
First, this line will make a deep copy of the image data, which is a waste.

uchar* imgBits = image.bits();

So it is better to add const.

Second, since QImage does not support multiple planes, there will always be only plane 0.

Then the important point, have you tried print

qDebug() << planeBytes << image.sizeInBytes();

You probably will see planeBytes is not same as image.sizeInBytes()
That's what I suppose why memcpy would have access violation, the data size in QVideoFrame is aligned and maybe bigger than QImage. So what you should do is copy data line by line.

I modified your code to

QVideoFrameFormat format(image.size(), QVideoFrameFormat::pixelFormatFromImageFormat(image.format()));
QVideoFrame frame(format);
if (!frame.isValid() || frame.planeCount() <= 0) {
    qDebug() << "Error: Invalid video frame format";
    // Handle error
} else {
    if (!frame.map(QVideoFrame::ReadWrite)) {
        qDebug() << "Error: Failed to map video frame";
        // Handle error
    } else {
        // Check if mapping succeeded
        qDebug() << "Video frame mapped successfully";
        uchar* frameBits = frame.bits(0);
        const uchar* imgBits = image.constBits();
        const int planeBytes = frame.mappedBytes(0);

        // Check if sizes match for this plane
        if (frameBits && imgBits && planeBytes >= 0) {
            const int lineBytesFrame = frame.bytesPerLine(0);
            const int lineBytesImage = image.bytesPerLine();
            const int imageHeight = image.height();
            for(int line = 0; line < imageHeight; line++){
                // Perform memcpy for each line
                //you can add error handling here since memcpy_s can return errors
                memcpy_s(frameBits, lineBytesFrame, imgBits, lineBytesImage);
                frameBits += lineBytesFrame;
                imgBits += lineBytesImage;
            }
            qDebug() << "Memcpy completed successfully";
        } else {
            qDebug() << "Error: Invalid pointer(s) or plane size";
            // Handle error
        }

        // Unmap the frame after memcpy
        frame.unmap();
    }

[iSolve_Tech]

@Bonnie Thanks you so much for your time I will modify the code you provide and will check .

[iSolve_Tech]

@Bonnie QVideoFrameFormat format(image.size(), QVideoFrameFormat::pixelFormatFromImageFormat(image.format()));
QVideoFrame frame(format);
if (!frame.isValid() || frame.planeCount() <= 0) {
qDebug() << "Error: Invalid video frame format";
// Handle error
} else {
if (!frame.map(QVideoFrame::ReadWrite)) {
qDebug() << "Error: Failed to map video frame";
// Handle error
} else {
// Check if mapping succeeded
qDebug() << "Video frame mapped successfully";
uchar* frameBits = frame.bits(0);
const uchar* imgBits = image.constBits();
const int planeBytes = frame.mappedBytes(0);

            // Check if sizes match for this plane
            if (frameBits && imgBits && planeBytes >= 0) {
                const int lineBytesFrame = frame.bytesPerLine(0);
                const int lineBytesImage = image.bytesPerLine();
                const int imageHeight = image.height();
                for(int line = 0; line < imageHeight; line++){ // srinadh
                    // Perform memcpy for each line
      

                    memcpy(frameBits, imgBits, lineBytesImage);
                   
                }
                qDebug() << "Memcpy completed successfully";
            }

            else {
                qDebug() << "Error: Invalid pointer(s) or plane size";
                // Handle error
            }

            // Unmap the frame after memcpy
            frame.unmap();
        }
    }
    Buffer updatedFrame = Buffer(frame);
    updatedFrame.copyTsFrom(newFrame);
    updatedFrame.setUnmodifiedVideoFrame(newFrame.videoFrame());
    newFrame = updatedFrame;
    qDebug()  << "image processed"; 

this memcopy is working fine in iOS and Windows but in android after am converting the image to frame I can able to see black screen

[iSolve_Tech]

@Bonnie Can you please give me some idea regarding the issue in android ?

am getting this error - freeAllBuffers: 1 buffers were freed while being dequeued!

[SGaist]

@iSolve_Tech Hi,

From old memories, I think that on Android, it's an OpenGL texture and you have to handle it accordingly.

[Bonnie]

@iSolve_Tech Sorry I don't develop on android, also this seems not related to this topic.

[iSolve_Tech]

@SGaist Thanks for your reply will check in that way