imwrite_('1.jpg'): can't write data: unknown exception about opencv HOT 3 OPEN

Hello, I'm sorry but if you want to ask question, https://forum.opencv.org/ is better.
But because you said an exception that is not cv::Exception occurred, I comment it.

As the necessary information has not been shared sufficiently at this time, we are unable to investigate the cause.
So I believe only you can investigate it .

As first, please could you split investigation in to 2 steps ?

• Step1 ) Determine which is this problem in commonly part or Jpeg part.
• Step2 ) (If jpeg part) Determine where line make exception.

Step1 ) Determine which is this problem in commonly part or Jpeg part.

"can't write data..." message is output from here. This is commonly part.

This is commonly part. Could you try with BMP encoder?

-	imwrite("1.jpg", t_frame[index]);
+	imwrite("1.bmp", t_frame[index]);

Step2 ) (If jpeg part) Determine where line make exception.

If this problem occurs with only "1.jpg", not "1.bmp". Please could you try to isolate the cause ?
JpegEncoder is very simple.

Or please could you share more information, like before and after log, Mat information ?
(It is difficult to investigate without reproducible data.)

https://github.com/opencv/opencv/blob/4.9.0/modules/imgcodecs/src/grfmt_jpeg.cpp#L580

Appendix

There are different between source code and comment, so maybe it is hard to determine which is input Mat valid or invalid.

	//* These judgements don't work.
	if (t_frame[index].empty() || t_frame[index].dims <= 0 || t_frame[index].channels() <= 0) {
		std::cout << "Mat is invalid." << t_frame[index].cols << ",h:" << t_frame[index].rows << std::endl;
	}
	else {
		//* isContinuous: true type：16
		std::cout << "Mat is valid,w:" << t_frame[index].cols << ",h:" << t_frame[index].rows << std::endl;
		std::cout << "Mat isContinuous:" << t_frame[index].isContinuous() << ";type:" << t_frame[index].type() << std::endl;
	}

For Jpeg Encoder...

• t_frame[index].empty() is needed.
• t_frame[index].dims <= 0 should be t_frame[index].dims == 2. But usually it is not needed.
• t_frame[index].channels() <= 0 should be check 1 or 3.
• 1920x1080 is OK, but it is not checked.
• isContinuous is not important because JpegEncoder handle each lines.
• type:16 ( CV_8UC3 ) is OK, but it is not checked, only comment.

from opencv.

Hello, I'm sorry but if you want to ask question, https://forum.opencv.org/ is better. But because you said an exception that is not cv::Exception occurred, I comment it.

As the necessary information has not been shared sufficiently at this time, we are unable to investigate the cause. So I believe only you can investigate it .

As first, please could you split investigation in to 2 steps ?

• Step1 ) Determine which is this problem in commonly part or Jpeg part.
• Step2 ) (If jpeg part) Determine where line make exception.

Step1 ) Determine which is this problem in commonly part or Jpeg part.

"can't write data..." message is output from here. This is commonly part.

opencv/modules/imgcodecs/src/loadsave.cpp

Lines 769 to 776 in dad8af6

	catch (const cv::Exception& e)
	{
	CV_LOG_ERROR(NULL, "imwrite_('" << filename << "'): can't write data: " << e.what());
	}
	catch (...)
	{
	CV_LOG_ERROR(NULL, "imwrite_('" << filename << "'): can't write data: unknown exception");
	}

This is commonly part. Could you try with BMP encoder?

-	imwrite("1.jpg", t_frame[index]);
+	imwrite("1.bmp", t_frame[index]);

Step2 ) (If jpeg part) Determine where line make exception.

If this problem occurs with only "1.jpg", not "1.bmp". Please could you try to isolate the cause ? JpegEncoder is very simple.

Or please could you share more information, like before and after log, Mat information ? (It is difficult to investigate without reproducible data.)

https://github.com/opencv/opencv/blob/4.9.0/modules/imgcodecs/src/grfmt_jpeg.cpp#L580

Appendix

There are different between source code and comment, so maybe it is hard to determine which is input Mat valid or invalid.

	//* These judgements don't work.
	if (t_frame[index].empty() || t_frame[index].dims <= 0 || t_frame[index].channels() <= 0) {
		std::cout << "Mat is invalid." << t_frame[index].cols << ",h:" << t_frame[index].rows << std::endl;
	}
	else {
		//* isContinuous: true type：16
		std::cout << "Mat is valid,w:" << t_frame[index].cols << ",h:" << t_frame[index].rows << std::endl;
		std::cout << "Mat isContinuous:" << t_frame[index].isContinuous() << ";type:" << t_frame[index].type() << std::endl;
	}

For Jpeg Encoder...

• t_frame[index].empty() is needed.
• t_frame[index].dims <= 0 should be t_frame[index].dims == 2. But usually it is not needed.
• t_frame[index].channels() <= 0 should be check 1 or 3.
• 1920x1080 is OK, but it is not checked.
• isContinuous is not important because JpegEncoder handle each lines.
• type:16 ( CV_8UC3 ) is OK, but it is not checked, only comment.

Hello, I'm sorry but if you want to ask question, https://forum.opencv.org/ is better. But because you said an exception that is not cv::Exception occurred, I comment it.

As the necessary information has not been shared sufficiently at this time, we are unable to investigate the cause. So I believe only you can investigate it .

As first, please could you split investigation in to 2 steps ?

• Step1 ) Determine which is this problem in commonly part or Jpeg part.
• Step2 ) (If jpeg part) Determine where line make exception.

Step1 ) Determine which is this problem in commonly part or Jpeg part.

"can't write data..." message is output from here. This is commonly part.

opencv/modules/imgcodecs/src/loadsave.cpp

Lines 769 to 776 in dad8af6

	catch (const cv::Exception& e)
	{
	CV_LOG_ERROR(NULL, "imwrite_('" << filename << "'): can't write data: " << e.what());
	}
	catch (...)
	{
	CV_LOG_ERROR(NULL, "imwrite_('" << filename << "'): can't write data: unknown exception");
	}

This is commonly part. Could you try with BMP encoder?

-	imwrite("1.jpg", t_frame[index]);
+	imwrite("1.bmp", t_frame[index]);

Step2 ) (If jpeg part) Determine where line make exception.

If this problem occurs with only "1.jpg", not "1.bmp". Please could you try to isolate the cause ? JpegEncoder is very simple.

Or please could you share more information, like before and after log, Mat information ? (It is difficult to investigate without reproducible data.)

https://github.com/opencv/opencv/blob/4.9.0/modules/imgcodecs/src/grfmt_jpeg.cpp#L580

Appendix

There are different between source code and comment, so maybe it is hard to determine which is input Mat valid or invalid.

	//* These judgements don't work.
	if (t_frame[index].empty() || t_frame[index].dims <= 0 || t_frame[index].channels() <= 0) {
		std::cout << "Mat is invalid." << t_frame[index].cols << ",h:" << t_frame[index].rows << std::endl;
	}
	else {
		//* isContinuous: true type：16
		std::cout << "Mat is valid,w:" << t_frame[index].cols << ",h:" << t_frame[index].rows << std::endl;
		std::cout << "Mat isContinuous:" << t_frame[index].isContinuous() << ";type:" << t_frame[index].type() << std::endl;
	}

For Jpeg Encoder...

• t_frame[index].empty() is needed.
• t_frame[index].dims <= 0 should be t_frame[index].dims == 2. But usually it is not needed.
• t_frame[index].channels() <= 0 should be check 1 or 3.
• 1920x1080 is OK, but it is not checked.
• isContinuous is not important because JpegEncoder handle each lines.
• type:16 ( CV_8UC3 ) is OK, but it is not checked, only comment.

imwrite_('1.bmp'): can't write data: unknown exception

How can I catch this error, at the moment the program just exits

from opencv.

@JianJingGao

Step1

I said you should try with BMP encoder instead of JPEG encoder.
How about it ? Does it works well?

And please notice that we cannot help you and/or debug your program because no one can reproduce your problem in other environment,
If you don't want to investigate/debug, this problem will not fixed forever. If so, It is better to close this issue.

(BTW a quoting all of previous comment is not meaning.)

from opencv.