So I decided to try making a screen recorder and I was following a tutorial.
So, the code works exactly as it should but after I finish the code and try running the .avi file I get the following error:
I searched around the web but I couldn't find the answer for my question, you guys have any idea?
OpenCV uses FFMPEG under the hood and ships release builds without the proprietary codecs you often need. I’ve been compiling OpenCV from source for 10 years and have successfully gotten good and repeatable codecs maybe once. Here are my recommendations...
Did the video play in VLC? That often is more forgiving. Use VLC first to troubleshoot the rest of your code if it plays there.
Play with many different FOURCC codes. When using only free codecs, you have to iterate through a lot of them before finding a valid match. Also, I’ve found that settings such as too low a frame rate can cause players to not work well.
Build a copy of FFMPEG from source with non-free drivers, then build OpenCV from source using those. This is a rabbit hole of doom though cause each codec is itself a separate package and install. You will spend a lot of time learning how to build software.
Use OpenCV for image processing and write video using a video writer API directly. Libav/FFMPEG, libx264, and others all have direct callable APIs so you can use them.
Related
I have spent weeks looking for a way to turn my webcam (built into the computer) into a QR scanner using Python but nothing has worked.
In the first instance, I tried installing this software which supposedly would allow me to turn my camera into a barcode scanner, which could then use this video to decode the codes in python. I installed the scanner along with 'pywin32' which was supposedly the library I needed to use, but I couldn't get the two to communicate as my computer kept saying that pywin32 has not been installed (although it had).
Then, I moved onto using zbar/ pyzbar. I downloaded all of the modules that were recommended (I followed the instructions set out on here) but these each came with several more error messages. It was all to do with various libraries and modules not being installed - I've tried downloading PIL/pillow, pyqrcode and a number of other things that are supposed to work, but for some reason, don't.
I don't feel that I can provide any evidence of code as I haven't got any code to fix for this particular issue -- I am simply looking for anyone who may know of a way to transform an ordinary webcam into a barcode/qr scanner using python.
Assuming none of the libraries I need are installed on my computer at the moment, could someone please explain to me exactly which libraries I will need to download, where I can find them, and how I could use them to make Python communicate with my webcam?
This is for my A Level Coursework and the scanner is absolutely fundamental to the program; if anyone can provide me with a useful, understandable solution then I would be really grateful. I apologise if this question is still a little too broad - I am a complete novice to coding and after searching endlessly for hours to find a solution, I feel that this is my final resort.
I did a project on zbar a couple of years ago, and it took 6 months to get zbar working :)
Here's how I setup zbar:
Zbar python module does require zbar.exe. Go to http://zbar.sourceforge.net/download.html and click either ZBar 0.10 Windows installer if you have windows, or Linux builds. Run zbar-0.10-setup.exe and follow installation instructions.
The Zbar python module is available on pypi. That means a simple pip install zbar will install it.
To get .py examples of Zbar running, first download the source code for zbar (top link on http://zbar.sourceforge.net/download.html ), unzip the tar.bz2 file (use 7zip). Inside the unzipped folder there should be /examples. Inside the folder, you will find several examples (proccessor.py is a good one), which can be run just as you would normally run a python program.
PointGrey is a leading manufacturer of machine vision cameras, but unfortunately their support for Mac OS is very limited. A www search led me to guess that I need to install libusb and libdc1394 in order to recognize the camera, which i did using brew. This did not work.
I don't understand exactly how libusb and libdc1394 libraries work under the hood, other than that they handle the hand-shaking with the camera and data transfer via the USB bus. OpenCV usually makes it incredibly easy to open a camera and start processing frames, but unfortunately when it doesn't work it's not clear how to debug. I found python wrappers for libusb and libdc1394 and included them in my code, which resulted in no errors, but no luck grabbing frames either.
If you don't have an exact answer, suggest strategies for solving this problem i.e. how should I systematically approach this, diagnosing all the possible failure modes. Is there a way that I can see more of what's going on when OpenCV tries to detect and read from a camera?
My python/opencv code works well with a simple capture = cv2.VideoCapture(0)
but doesn't work with capture = cv2.VideoCapture(1), giving output as follows:
Warning, camera failed to properly initialize!
Cleaned up camera.
Typically cv2.VideoCapture(0) will give the built-in camera on my macbook, and from what I understand cv2.VideoCapture(1) will give the next available camera (i.e. plugged in through USB).
I know the camera works well on a windows machine (in Windows Movie Maker). Do I need to do something further under the hood to get python and opencv to recognize the camera under OS X?
Many years later, we can answer this question. FLIR, which acquired PointGrey, has released Spinnaker, a cross-platform SDK with a UI and a set of pre-compiled examples for accessing the camera: https://www.flir.com/support-center/iis/machine-vision/downloads/spinnaker-sdk-and-firmware-download/
I'm trying to get the wxPython video player described here to work in Windows, so that I can do some minor modifications to it and get a script running that will let a user hit the spacebar while watching a video and spit out a record of the timing of each spacebar press. So far, though, I can't even get the videoplayer working; when I try to open a video, I get the following error message:
Unable to load (filename): Unsupported format?
A little google searching turned up the possibility that I might be missing gstreamer packages, so I installed the closest thing I could find from here, but it still doesn't work. What exactly do I need to have installed to get wxPython to play videos, and how do I install it?
Thanks!
wxPython should use GStreamer on Linux, if available. See http://wxpython-users.1045709.n5.nabble.com/wxpython-gstreamer-and-overlapping-panel-staticText-td4834139.html or http://pythonide.blogspot.com/2008/03/howto-write-wxpython-video-player-with.html although I don't see why that matters when the OP was talking about Windows.
I created a simple media player using the mplayer control. You can read about it here: http://www.blog.pythonlibrary.org/2010/07/24/wxpython-creating-a-simple-media-player/ It was tested on Windows XP and Windows 7 with no issues.
I have this question in my head for over a year now. And I guess you guys may have the answer.
In some Python GUI app, I need to display a video stream.
I need to record some part of this stream to reread it later.
Moreover, I need to make this python application multi platform (OSX, GNU, Windows)
I am open to many solutions :
Connect the camera to a stream and read the stream with the python app. (RTP + VLC could do the trick)
Use Phonon to read the camera
Create an abstract class to define differents reader and use Quicktime, Win32 or GStreamer in function of the OS.
What is your experience, what would you use to do that ?
I've looked into this periodically as well, and it seems the complexity of the underlying task is just too high to have a simple shortcut abstraction library for your topic question. I would suggest using pyopencv for the specific task you articulate, however. It has a class for webcam input/capture which works across platforms and has a reasonable user-base, in python, posting examples. The latest is 2.3.1 and quite recent. You can get a windows version of it, compiled for you, on the unbelievably helpful site (not mine, just saying):
http://www.lfd.uci.edu/~gohlke/pythonlibs/
Since you ask for experience with a few libraries, I'd say: gstreamer worked for me on linux but was a huge pain to setup on windows and didn't work for me. This was quite some time ago and perhaps it's working better now. vlc.py is a simple library to test and see whether vlc would work for you. It doesn't work on 64 bit windows platforms at the moment; not sure why, but it seems many have reported similar errors, so it depends on how much cross-platform support you need.
Unfortunately, this is not easy to do. I've written most of a program that does video recording/playback on the 3 major desktop OS's. The state of video playback/recording in a "out-of-the-box" way is still unsolved for cross-platform, other than HTML embedding. This has a lot to do with the fact that:
Codecs are proprietary
OS's don't support common codecs
ffmpeg and similar projects have licenses that require you to release your source code if you include them in certain ways
A lot of the video playback players that exist are each rewritten by hand to handle each frame, buffering, streaming, audio sync'ing, and the like.
So you can go with HTML, or you can suffer through the cross-platform issues with the following coding libaries:
Python mplayer
Python vlc
Python opencv
Python pyaudio
Python pyside/pyqt phonon or qtmultimedia
Once you get it working on one development machine, expect it to break when it comes to installation on the end-user machine (distribute via: pyinstaller / appdmg / apt / chocolatey / Inno Setup )
On OSX, brew still has a lot of issues with this, but macports works better (I still had to do a lot of patching)
Linux is by far the easiest.
Windows is in-between the to as far as difficulty
I'd be eager to hear how iOS / Android / Windows RT / Kindle are
The problem is not unique, as even Netflix has yet to have a cross-platform video app: https://www.quora.com/Is-Netflix-building-an-app-for-the-Mac-App-Store?share=1
I'm trying to write my own media player (like Foobar), and I'm having trouble tracking down a Python library that'll play MP3s. I know Pymedia does mp3s, but it looks outdated - the latest installer is for Python version 2.4, and I'm using 2.6. I've never had much success with Pygame, and Pyglet doesn't look like it has too much in the way of documentation. Are there any other alternatives?
There is http://pyglet.org/ and also have you tried http://code.google.com/p/mp3play/? It's also available from PyPi (http://pypi.python.org/pypi/mp3play/) However, I think mp3play is Win32 only for now.
Looking at the updates, there were commits within last couple of months.
I've been using PyMedia in Python 2.6.5 on Windows successfully. Caveats: the documentation is bad and wrong -- many of the tutorials have glaring errors or otherwise don't work -- so I had to do some experimentation and Googling to get my code to work right. Also for whatever reason the maintainers seem to have stopped updating the project site 4 years ago, though they seem to be actively doing something.
I found installers here:
http://www.lfd.uci.edu/~gohlke/pythonlibs/
The semi-active forum linked from their website includes some code maintainers who are semi-helpful. I'm jboyd99 if anyone is looking for tips.
For reasons that are beyond me the focus is on car audio systems, despite the fact that it is a fairly fully featured library that does some things no other free Python library does, like read MP3s into raw PCM data. The library has some flaws -- I'll probably use PyAudio or PyAudiere for actual playback for better control of synchrony issues.
Maybe it'd be simpler to write that part of your application in Python 2.4 as a separate "backend". This way you could use PyMedia (http://pymedia.org/) (as you mentioned) for the actual playback. It'd allow you to write your GUI in another Python version (like 2.6), which would also mean more decoupling of program components and parallelism (smoother GUI).
If you target only the Windows platform, then using Media Player via COM might help:
http://www.daniweb.com/code/snippet216465.html