I work on a 16.04 system, and have successfully installed opencv 3.1 with FFMPEG flags enabled. I double checked this was actually the case by cv2.getBuildInformation() and I got FFMPEG = YES.
I am trying to open a video that is hostel on a private server by my workplace (I am logged in to the VPN, in case thats a concern) and I can access this video over the browser. But videocapture with cv2 fails.
>>> cap = cv2.VideoCapture("https://xxx.mp4", cv2.CAP_ANY) #dummy url
>>> cap
<VideoCapture 0x7f63300fa4b0>
>>> cap.isOpened()
False
This is always the case for https urls. It seems to be able to work with local videos just fine. I have tried a bunch of different thing: initially thought it was a gstreamer problem so I checked my plugins, had some gst-bad versions (ref: https://github.com/GStreamer/gst-plugins-ugly), removed those and replaced with good versions, no joy. Also tried to explicitly tell videoCapture to use cv2.CAP_ANY and cv2.CAP_FFMPEG flags while reading the video, still no luck.
I disabled the Gstreamer flag while compiling opencv, but even with it set to ON, there was no difference in my problem.
I haven't been able to find a solution to this issue and have been looking and trying different things for days now! Any ideas?
Eventually, I gave up on trying to install and reinstall opencv3.1, and switched to opencv 3.4.1. With that, and my current (as original question post) configuration for gstreamer and ffmpeg, I only had to create symlinks for libopencv_core.so.2.4 that gstreamer was looking for, and the rest of it worked fine.
Hope this helps someone!
I haven't managed to figure out what exactly was the issue with opencv3.1 (like I mentioned, that is the configuration my other colleagues have, and the functionality works just fine for them) but this is what I ended up doing after spending days on the issue.
Related
As it's mentioned in Release highlights, OpenCV (4.5.5) now have Audio support in videoio module. However, there's no documentation related on this topic.
I've tried a few things on my own like:
cv::VideoCapture cap(fileName,cv::CAP_MSMF);
However, no results so far.
How can I activate Audio Support? Am I missing something?
(Does not work neither for camera nor video files)
Additionally, I don't use pre-built binaries but, tried with pre-built ones(for Windows) and it didn't work neither.
As far as I see, this question does not make any sense unless they implement an interface. That's why they have no documentation about this topic. Hope they'll bring that feature with 4.5.6.
I am trying to remove opencv fully from my system. I was trying to learn ROS, while in tutorials I faced an issue. After creating empty workspace I invoke
catkin_make
It gives an common error, I searched and asked around in answers.ros
here is the link of the question
I think I found out the problem was opencv libraries which I had build before installing ROS-Noetic, creating the error, I searched around how to remove opencv, but non of the answers totally remove opencv without removing my opencv names files.
Is there a common solution on how to remove opencv?
Ubuntu 20.04
ROS Noetic
Best way if you installed opencv from source and still have the build directory, simply go there and call make uninstall. Another solution is to delete all opencv related files as you already know and suggested in many other similar questions like this. You could also try to use synaptic package manager if you installed using a package.
I suggest for the future to install development libraries a custom folder, so it will be just a matter of deleting that folder if something goes wrong. In this way you can also have different opencv versions in your system, this is how I do.
I've hit a roadblock with using GPUImage. I'm trying to apply a filter (SepiaFilter or OpacityFilter) on a prerecorded video. What I'm expecting to see is the video played back with the filter applied to it. I followed the SimpleFileVideoFilter example for my code. What I ended up with is a video that is unplayable by Quicktime (m4v extension) and the live preview of the rendering all skewed. I thought it was my code at first so I ran the example app from the examples directory and lo and behold I got the same issue. Is the library broken? I just refreshed from master out of GitHub.
Thanks!
Here's a sample output of the video generated
http://youtu.be/SDb9GfVf9Lc
No matter what filter is applied the resultant video are all similar. (all skewed )
#Brad Larson (I hope you see this message), do you know what I can be doing wrong? I am using the latest XCode and source code of GPUImage. I also tried using the latest from CocoaPods as well. Both end up the same.
I assume you're trying to run this example via the Simulator. Movie playback in the Simulator has been broken for as long as I can remember. You need to run this on an actual device to get movie playback to work.
Unfortunately, one of the recent pull requests that I brought in appears to have introduced some crashing bugs even there, and I may need to revert those changes and figure out what went wrong. Even that's not an iOS version thing, it's a particular bug with a recent code addition. I haven't had the time to dig into it and fix it, though.
I have the following issue, I cannot find a solution on the web, please let me know if you can help me or point me to a proper info about this issue.
To understand the background, Im porting a game from flashDevelop to Flash Builder (please dont give me tips about this comment if doesn't help to my particular problem). Everything works fine right now, the game use a file null.swf as a container of local files (I don't undertand that part completely, but the game has a lot of embed swc files, and the game use the null.swf to access those files, through LoaderMax).
The problem is that everything works fine with a fast build, but it's not working with a standard build, I have the error on Loader class that says "Multiple application domains are not supported on this operating system".
Useful information:
Im using AIR 3.9, compilation flash swf-version=20 (I had 18 when I started with this issue)
null.swf is properly included on the IPA, the code recognize the file, and as I said before it works with a fast build.
For embed swc files, I had to include the files with a compiler argument: "-include-libraries ../../filename.swc ../../filename2.swc etc.."
Thanks for any help.
Regards
It's fixed, using a context:
context = new LoaderContext(false, ApplicationDomain.currentDomain, null);
If I use the third parameter, like ..., SecurityDomain.currentDomain); it doesn't work.
I am running Python2.7.1 and OpenCV 2.2 without problems in my WinXP laptop and wrote a tracking program that is working without a glitch. But for some strange reason I cannot get the same program to run in any other computer where I tried to install OpenCV and Python (using the same binaries or appropriate 64 bit binaries). In those computers OpenCV seems to be correctly installed (although I have only tested and CaptureFromCamera() in the webcam of the laptop), but CaptureFromFile() return 'None' and give "error: Array should be CvMat or IplImage" after a QueryFrame, for example.
This simple code:
import cv /
videofile = cv.CaptureFromFile('a.avi') /
frame = cv.QueryFrame(videofile) /
print type(videofile) /
print type(frame)
returns:
type 'cv.Capture' /
type 'NoneType'
OpenCV and Python are in the windows PATH...
I have moved the OpenCV site-packages content back and forth to the Pyhton27 Lib\Site-packages folder.
I tried different avi files (just in case it was some CODEC problem). This AVI uses MJPEG encoding (and GSpot reports that ffdshow Video Decoder is used for reading).
Images work fine (I think): the simple convert code:
im = cv.LoadImageM("c:\tests\colormap3.tif")
cv.SaveImage("c:\tests\colormap3-out.png", im)
opens, converts and saves the new image...
I have tested with AVI files in different folders, using "c:\", "c:/", "c:\" and "c://".
I am lost here... Anyone has any idea of what stupid and noob mistake may be the cause of this? Thanks
It may sound stupid, but I just had the same issue with the same symptoms for the same code snippet (Python 2.7.1, Win 7, OpenCV 2.2.0). I changed file path from
capture = cv.CaptureFromFile('C:\Misc\tree.avi')
to
capture = cv.CaptureFromFile('C:/Misc/tree.avi')
and voila
<type 'cv.Capture'>
<type 'cv.iplimage'>
I was having this problem, and here is how I fixed it. I took a look at the output of OpenCV's cmake command, and it had the following line:
...
-- FFMPEG: NO
...
In order to fix this, you might be able to get away with simply installing the following libraries:
sudo apt-get install libavformat-dev libavcodec-dev libavfilter-dev libswscale-dev
Re-running cmake will hopefully now say:
...
-- FFMPEG: YES
...
Re-compile OpenCV, re-install it, and hopefully you can now read videos. If you still have problems, you can try to compile ffmpeg using the --enable-shared option, using these as guides:
http://opencv.willowgarage.com/wiki/FFMPEG
http://ubuntuforums.org/showthread.php?t=786095
Hope that helps.
This must be an issue with the default codecs. OpenCV uses brute force methods to open video files or capture from camera. It goes by trial and error through all sources/codecs/apis it can find in some reasonable order. (at least 1.1 did so).
That means that on n different systems (or days) you may get n different ways of accessing the same video. The order of multiple webcams for instance, is also non-deterministic and may depend on plugging order or butterflies.
Find out what your laptop uses, (re)install that on all the systems and retry.
Also, in the c version, you can look at the capture's properties
look for cvGetCaptureProperty and cvSetCaptureProperty where you might be able to hint to the format.
[EDIT]
Just looked i tup in the docs, these functions are also available in Python. Take a look, it should help.