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Description
Transferred from http://code.opencv.org/issues/1938
|| Dmitry Kit on 2012-05-15 16:14
|| Priority: Normal
|| Affected: None
|| Category: python bindings
|| Tracker: Bug
|| Difficulty: None
|| PR: None
|| Platform: None / None
Python cv2.VideoCapture.read() does not read all frames
I have some python code that tries to read all the frames from a video file (attached). However, using the following loop:
<pre>
g_capture = cv2.VideoCapture('fence.wmv')
ret = True
while ret:
ret,im = g_capture.read()
cv2.imshow("video", im)
cv2.waitKey(2)
</pre>
results in only ~178 or so frames read before ret becomes False and things start failing. However, when I do:
<pre>
g_capture.set(cv2.cv.CV_CAP_PROP_POS_FRAMES, 201)
</pre>
I correctly get the frame 201. Furthermore the following C code works just fine:
<pre>
int main(int argc, char* argv[])
{
CvCapture* capture = cvCaptureFromAVI("fence.wmv");
IplImage* img = 0;
while(true) {
if(!cvGrabFrame(capture)){ // capture a frame
printf("Could not grab a frame\n\7");
cvWaitKey();
exit(0);
}
img=cvRetrieveFrame(capture); // retrieve the captured frame
cvShowImage("mainWin", img);
cvWaitKey(20); // wait 20 ms
}
cvReleaseCapture(&capture);
}
</pre>
I am using the svn version of opencv source code (from about 3 days ago) and I have tried to convert the original video to a supported avi format using the mencoder command found on http://opencv.willowgarage.com/wiki/VideoCodecs .
This bug might be a duplicate of http://code.opencv.org/issues/1690
History
Dmitry Kit on 2012-05-24 23:20
Realized I forgot to follow some instructions when I filed this bug:
The opencv build information is included below:
<pre>
General configuration for OpenCV 2.4.0 =====================================
Version control: svn:8335
Platform:
Host: Windows 6.1 x86
CMake: 2.8.8
CMake generator: Visual Studio 10
CMake build tool: /MICROS~1.0/Common7/IDE/devenv.com
MSVC: 1600
C/C++:
Built as dynamic libs?: YES
C++ Compiler: cl
C++ flags (Release): /DWIN32 /D_WINDOWS /W4 /EHs /GR /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /arch:SSE /arch:SSE2 /Oi /fp:fast /wd4251 /MP8 /MD /O2 /Ob2 /D NDEBUG /Zi
C++ flags (Debug): /DWIN32 /D_WINDOWS /W4 /EHs /GR /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D_SCL_SECURE_NO_WARNINGS /Gy /bigobj /arch:SSE /arch:SSE2 /Oi /fp:fast /wd4251 /MP8 /D_DEBUG /MDd /Zi /Ob0 /Od /RTC1
C Compiler: cl
C flags (Release): /DWIN32 /D_WINDOWS /W3 /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /arch:SSE /arch:SSE2 /Oi /fp:fast /MP8 /MD /O2 /Ob2 /D NDEBUG /Zi
C flags (Debug): /DWIN32 /D_WINDOWS /W3 /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /arch:SSE /arch:SSE2 /Oi /fp:fast /MP8 /D_DEBUG /MDd /Zi /Ob0 /Od /RTC1
Linker flags (Release): /STACK:10000000 /machine:X86 /INCREMENTAL:NO /debug
Linker flags (Debug): /STACK:10000000 /machine:X86 /debug /INCREMENTAL
OpenCV modules:
To be built: calib3d contrib core features2d flann gpu highgui imgproc legacy ml nonfree objdetect photo python stitching ts video videostab
Disabled by user: world
Disabled by dependency: -
Unavailable: androidcamera java
GUI:
QT 4.x: YES (ver 4.7.4 EDITION = OpenSource)
QT OpenGL support: YES (optimized /x32/qt/lib/QtOpenGL4.lib debug /x32/qt/lib/QtOpenGLd4.lib)
OpenGL support: YES (glu32 opengl32)
Media I/O:
ZLib: build (ver 1.2.6)
JPEG: build (ver 62)
PNG: build (ver 1.5.9)
TIFF: build (ver 42)
JPEG 2000: build (ver 1.900.1)
OpenEXR: NO
OpenNI: NO
OpenNI PrimeSensor Modules: NO
XIMEA: NO
Video I/O: DirectShow
FFMPEG: YES (prebuilt binaries)
codec: YES (ver 53.61.100)
format: YES (ver 53.32.100)
util: YES (ver 51.35.100)
swscale: YES (ver 2.1.100)
gentoo-style: YES
Other third-party libraries:
Use IPP: NO
Use TBB: YES (ver 4.0 interface 6004)
Use Cuda: YES (ver 4.2)
Use Eigen: NO
Use Clp: NO
NVIDIA CUDA: (ver 4.2)
Use CUFFT: YES
Use CUBLAS: YES
NVIDIA GPU arch: 11 12 13 20 21 30
NVIDIA PTX archs: 11 12 13 20 21 30
NVIDIA GPU features: 11 12 13 20 20 30 20
Python:
Interpreter: /Python27/python.exe (ver 2.7.2)
Libraries: /Python27/libs/python27.lib (ver 2.7.2)
numpy: /Python27/lib/site-packages/numpy/core/include (ver 1.6.1)
packages path: /Python27/Lib/site-packages
Documentation:
Build Documentation: NO
Sphinx: NO
PdfLaTeX compiler: /MiKTeX 2.9/miktex/bin/x64/pdflatex.exe
Tests and samples:
Tests: YES
Performance tests: YES
Examples: NO
Install path: /opencv_new/trunk/opencv/build32/install
cvconfig.h is in: /opencv_new/trunk/opencv/build32
-----------------------------------------------------------------
</pre>
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