I'm trying to use the opencv librarie to display video files to the screen using sdl-2. I got it to work with smaller files(20.5Mb), but when i tryed using bigger files (100 and 136Mb) it didnt work and i go the message "ERROR: Coudnt load the video < video.avi>".
cv::VideoCapture video;
video.open(videoName);
if (!video.isOpened())
{
SDL_Log("ERROR: Coudnt load the video <%s>", videoName.c_str());
return;
}
I don't know if size was the problem, but that would make the most sense to me. I've not found any documentation on size restrictions thought. Any ideas on how to fix it?
PS: All were .avi files, and the file's name was not the problem. Was able to open them with ffplay if that matters at all. OpenCV version 2.4.8
Related
Hi stackoverflow community,
I recently had a problem with the performance of the opencv VideoWriter (see here), and I am now using cv::CAP_OPENCV_MJPEG as a backend instead of cv::CAP_FFMPEG.
Now I am running in another issue, so my code looks like this:
cv::VideoWriter videoWriter(path, cv::CAP_OPENCV_MJPEG, fourcc, fps, *size);
videoWriter.set(cv::VIDEOWRITER_PROP_QUALITY, 100);
int id = metaDataWriter.insertNow(path);
while (this->isRunning) {
while (!this->stackFrames.empty()) {
cv:Mat m = this->stackFrames.pop();
videoWriter << m;
}
}
videoWriter.release();
This loop runs in a separate thread and "isRunning" will be switched from outside. There is a stack with cv::Mat (stackFrames) which is filled by another thread that captures the images by a video capture card. This works fine, but if the file size is too big, several GB, I get the following error when the videoWriter.release() is called:
terminate called after throwing an instance of 'cv::Exception'
what(): OpenCV(4.4.0) /home/michael-gary/opencv/opencv/modules/videoio/src/container_avi.cpp:27: error: (-211:One of the arguments' values is out of range) Failed to write AVI file: chunk size is out of bounds in function 'safe_int_cast'
I tried to change the video container from .avi to .mkv, .mp4, .mpg but none of them is working, it does not even create the file. Only .avi is working, but fails by the release.
For now I will try to write multiple files, so I don't run in this problem, but I would like to face the problem itself.
Open for any suggestions
BR Michael
AVI files are practically limited in size.
when you force it to use OPENCV_MJPEG, it will only use OpenCV's own writing methods, which can only do AVI and MJPEG.
if you need a different container, you have to use a different backend, such as FFMPEG. you can still have MJPG for a codec (fourcc).
I am trying to encode a video using MediaFoundation on Windows 8.1, the output file should be an avi container, with a raw stream NV12.
The video is generated, and I can play it but when I open it with VLC I get the broken index detected (With options to play as is or fix it temporarly). If I press play as is, it plays ok. But this is generating a problem in other softwares.
I tried to research this and noticed that AVI supports 2 types of indexing
https://msdn.microsoft.com/en-us/library/windows/desktop/dd318189(v=vs.85).aspx
But this is for DirectShow and I am using MediaFoundation and I can't find anything related to this inside MediaFoundation.
Any help or suggestion will be appreciated.
Thanks.
Edit:
This is how I am creating the IMFMediaSink:
hr = MFCreateAttributes(&sinkAttributes, 5);
assert(SUCCEEDED(hr));
sinkAttributes->SetUnknown(MF_SINK_WRITER_ASYNC_CALLBACK, this);
sinkAttributes->SetGUID(MF_TRANSCODE_CONTAINERTYPE, MFTranscodeContainerType_AVI);
if (SUCCEEDED(hr)){
hr = MFCreateSinkWriterFromURL(videoURL, NULL, sinkAttributes, (IMFSinkWriter**)&sinkWriter);
}
I'm trying to compare 3 videos that are encoded by H.264, H.265, and VP9.
All of them are made by a same YUV video.
I want to use OpenCV's function to read each frame of the video and do some comparison:
VideoCapture vCap1, vCap2, vCap3;
vCap1.open("h264.mp4");
vCap2.open("h265.mp4");
vCap3.open("vp9.webm");
Mat frame1, frame2, frame3;
while (vCap1.read(frame1) && vCap2.read(frame2) && vCap3.read(frame3))
{
//do something
}
The vCap1 opened successfully, but vCap2 and vCap3 won't open.
Did I miss something to include to make it work?
Or OpenCV even not support the other 2 formats?
After using google :-) I found that
http://answers.opencv.org/question/10741/videocapture-format-supported-by-opencv/
Especially you have the needed codecs installed on your system. You can visit also
http://www.fourcc.org/codecs.php
for codecs.
The documentation from OpenCV is indeed not very helpful. :-)
What I would try if you are running under linux:
strace -xfo dump
and take a look in the system calls. Maybe you can find some hints of missing codec files, used configuration files and or other failed system function calls. If so, you have a startpoint.
I am reading in video files with openCV, I use the following simple code to do this.
std::string arg = argv[1];
VideoCapture capture(arg); //try to open string, this will attempt to open it as a video file
if (!capture.isOpened()) {
cerr << "Failed to open video file!\n" << endl;
help(argv);
system("Pause");
return 1;
}
I can load and manipulate several videos, but I have problems with others. I imagine this is down to codec issues. I can play the videos using old style win media player, so the codecs are on the system, but I imagine not available in opencv?
Does anyone know what codecs and video format will definitely play on opencv and what is a good option to convert video to these formats?
Many Thanks
Indeed, the supported codec of OpenCV is dependent on your platform and avaible codecs.
This tutorial Creating a video with OpenCV explains the video codec of OpenCV clearly. Though it is meant for writing videos, I think the underlying principle is the same with reading videos.
The function C++: double VideoCapture::get(int propId) can retrieve your loaded video's codec property by setting propId = CV_CAP_PROP_FOURCC. The interpretation of FOURCC can be found on this site. If you have problems with reading .avi videos, it is very likely that the codes is not installed in your platform.
I am trying to display video feed from IP- Camera(D-Link DCS 932L). I Have gone through topics for the same and tried the code from different posts, but am unable to get the video feed from the camera.
Here's the code which i tried.
#include <opencv/cv.h>
#include <opencv/highgui.h>
using namespace cv;
int main(int argc, char *argv[])
{
Mat frame;
namedWindow("video", 1);
String url = "http://admin:admin#172.32.20.55:80/image/jpeg.cgi";
VideoCapture cap(url);
/* VideoCapture cap(0);*/
while ( cap.isOpened() )
{
cap >> frame;
if(frame.empty()) break;
imshow("video", frame);
if(waitKey(30) >= 0) break;
}
return 0;
}
I tried many different kind of url's but i was unable to display any video feed. I thought it might be code problem so I even tried displaying the USB Webcam and it worked. So now i come to conclusion that the problem seems to be with URL which am passing. Heres the list of urls which I tried. I got this Url options from iSpy.Here are those URL's
(JPEG)http://admin:admin#172.32.20.55:80?IMAGE.JPG
(JPEG)http://admin:admin#172.32.20.55:80/image/jpeg.cgi
(MPEG)http://admin:admin172.32.20.55:80/video.cgi?resolution=VGA
(MPEG)http://admin:admin172.32.20.55:80/video/mjpg.cgi
(MPEG)http://admin:admin172.32.20.55:80/mjpeg.cgi? user=admin&password=admin&channel=0
(MPEG)http://admin:pnqadmin172.32.20.55:80/VIDEO.CGI
Please let me know what can be probable problem for displaying the video feed.
Is their something to do with the setting of the OpenCv or something else.Please note that am using VS2010 and C++ Need help of all the Expert out their.
Thanks in advance.
I solved my problem. The problem was with URL. I changed the URL and it worked smooth..!
The URL i used was as follows.
"http://USER:PWD#IPADDRESS:8088/mjpeg.cgi?user=USERNAME&password=PWD&channel=0&.mjpg";
I keep getting the same error:
warning: Error opening file <../../modules/highgui/src/cap_ffmpeg_impl.hpp:529>
I was trying to stream MJPG video from a Foscam IP camera. The URL opened just fine but I couldn't read any frames. May be there was some problem with the video codec.
Here's a hack written in Python that worked for me: https://stackoverflow.com/a/18411168/3183051
Perhaps my answer is too late. Check if opencv_ffmpegXXX.dll or opencv_ffmpegXXX_64.dll (if you are building 64bit executable) is in the same folder where your executable is. Replace XXX with the number of opencv version you use.