Tried a lot of options and am running out of ideas. I was hoping someone here could help. I am trying to write some code in python that will extract frames (say every tenth frame) from a video (.avi or .wmv) and create a picture (.jpg preferably - but other formats will do). I have had no success and was wondering if someone could assist me in solving my problem by providing an alternative to what I have tried and failed.
I have tried PyMedia (the example in their tutorial http://pymedia.org/tut/src/dump_video.py.html does not work - the program bombs out when it looks for the video codecs):
#dm= muxer.Demuxer( inFile.split( '.' )[ -1 ] ) This line does not work
dm= muxer.Demuxer( 'avi' ) #This modified line does seem to work however
i= 1
inFile = "VideoTest.avi"
f= open( inFile, 'rb' )
s= f.read( 400000 )
r= dm.parse( s )
v= filter( lambda x: x[ 'type' ]== muxer.CODEC_TYPE_VIDEO, dm.streams )
v_id= v[ 0 ][ 'index' ]
print 'Assume video stream at %d index: ' % v_id
c= vcodec.Decoder( dm.streams[ v_id ] ) #this is the point where it crashes.
I have tried OpenCV v2.2 for Python but that doesn't work either (I can get most of OpenCV to work - except the one function, CaptureFromFile, that I need does not work). I believe the reason this function doesn't work is because on Windows it requires highGui to operate and for some reason, python and opencv cannot find highgui eventhough it is in the correct directory. I also understand OpenCV has issues with finding and applying correct video codecs so I am not sure which is the cause of my problem.
I have looked at pyFFMPEG but the last build for that was version 2.6 and I am running python 2.7.
I am running this on Windows Vista and Windows 7 machines, have Python 2.7 and OpenCV 2.2 loaded on C:\ and all other python packages (pygames, pymedia, numpy, scipy) installed in C:\python27\Libs\site-packages..." I downloaded and installed from executables, all packages were built for python 2.7. My Path variable includes Python27 and OpenCV and I have a PYTHONPATH variable.
Thanks for any ideas or recommendations.
I tried the following to extract each frames as a separate image:
import cv2
file_path = "some\path\to\the\file.avi"
video_object = cv2.VideoCapture(path)
success = True
while success:
success,frame = video_object.read()
if success:
cv2.imwrite(path[:-4]+"_"+str(i)+".jpg",frame)
print("Done!")
This script saves each frame as an image in the same folder as the source file. It may not be the most efficient way to do this, but it works for me! I know my string parsing is not the most recommended, but it works.
video_object.read() returns two object. The first is a bool indicating whether the reading operation was a success or not, and the second is the image.
There may be limitations with respect to the video codec, of which I am not aware. I'm using Python 2.7 with the most recent version of openCV and Numpy as of 11/7/2013.
Related
The Darknet guide to detect objects in images using pre-trained weights is here: https://pjreddie.com/darknet/yolo/
The command to run is:
./darknet detect cfg/yolov3.cfg yolov3.weights data/dog.jpg
The last argument is the path to a file, I've tried to change it to data/*.jpg but didn't work.
How to use Darknet to detect a whole directory of images?
As per the link mentioned below, one can use cv2.dnn.readNetFromDarknet module to read darknet, trained weights and configuration file to make a loaded model in python. Once the model is loaded, one can simply use for loop for prediction.
Please refer this link for further clarification
There is a simple way to detect objects on a list of images based on this repository AlexeyAB/darknet.
./darknet detector test cfg/obj.data cfg/yolov3.cfg yolov3.weights < images_files.txt
You can generate the file list either from the command line (Send folder files to txt ) or using a GUI tool like Nautilus on Ubuntu.
Two extra flags -dont_show -save_labels will disable the user interaction, and save the detection results to text files instead.
There's a trick to make Darknet executable load weights once and infer multiple image files. Use expect to do the trick.
Install expect:
sudo yum install expect -y
#sudo apt install expect -y
Do object detection on multiple images:
expect <<"HEREDOC"
puts "Spawning...";
spawn ./darknet detect cfg/yolov3-tiny.cfg yolov3-tiny.weights;
set I 0;
expect {
"Enter Image Path" {
set timeout -1;
if {$I == 0} {
send "data/dog.jpg\r";
incr I;
} elseif {$I == 1} {
send "data/kite.jpg\r";
incr I;
} else {
exit;
}
exp_continue;
}
}
HEREDOC
Another solution is loading Darknet from Python2 (not 3, Darknet is using Python2).
1a) Clone darknet as described in https://pjreddie.com/darknet/yolo/
1b) Go to the cloned dir, download yolov3-tiny.weights and yolov3.weights as said in https://pjreddie.com/darknet/yolo/
2) Copy darknet/examples/detector.py to darknet dir
3) Edit the new detector.py
Change .load_net line to use: cfg/yolov3-tiny.cfg and yolov3-tiny.weights
Change .load_meta line to use: cfg/coco.data
4a) Detect objects in images by adding some dn.dectect lines in detector.py
4b) Run detector.py
I have added this (https://github.com/kewlbear/FFmpeg-iOS-build-script) version of ffmpeg to my project. I can't see the entry point to the library in the headers included.
How do I get access to the same text command based system that the stand alone application has, or an equivalent?
I would also be happy if someone could point me towards documentation that allows you to use FFmpeg without the command line interface.
This is what I am trying to execute (I have it working on windows and android using the CLI version of ffmpeg)
ffmpeg -framerate 30 -i snap%03d.jpg -itsoffset 00:00:03.23333 -itsoffset 00:00:05 -i soundEffect.WAV -c:v libx264 -vf fps=30 -pix_fmt yuv420p result.mp4
Actually you can build ffmpeg library including the ffmpeg binary's code (ffmpeg.c). Only thing to care about is to rename the function main(int argc, char **argv), for example, to ffmpeg_main(int argc, char **argv) - then you can call it with arguments just like you're executing ffmpeg binary. Note that argv[0] should contain program name, just "ffmpeg" should work.
The same approach was used in the library VideoKit for Android.
To do what you want, you have to use your compiled FFmpeg library in your code.
What you are looking for is exactly the code providing by FFmpeg documentation libavformat/output-example.c (that mean AVFormat and AVCodec FFmpeg's libraries in general).
Stackoverflow is not a "do it for me please" platform. So I prefer explaining here what you have to do, and I will try to be precise and to answer all your questions.
I assume that you already know how to link your compiled (static or shared) library to your Xcode project, this is not the topic here.
So, let's talk about this code. It creates a video (containing video stream and audio stream randomly generated) based on a duration. You want to create a video based on a picture list and sound file. Perfect, there are only three main modifications you have to do:
The end condition is not reaching a duration, but reaching the end of your file list (In code there is already a #define STREAM_NB_FRAMES you can use to iterate over all you frames).
Replace the dummy void fill_yuv_image by your own method that load and decode image buffer from file.
Replace the dummy void write_audio_frame by your own method that load and decode the audio buffer from your file.
(you can find "how to load audio file content" example on documentation starting at line 271, easily adaptable for video content regarding documentation)
In this code, comparing to your CLI, you can figure out that:
const char *filename; in the main should be you output file "result.mp4".
#define STREAM_FRAME_RATE 25 (replace it by 30).
For MP4 generation, video frames will be encoded in H.264 by default (in this code, the GOP is 12). So no need to precise libx264.
#define STREAM_PIX_FMT PIX_FMT_YUV420P represents your desired yuv420p decoding format.
Now, with these official examples and related documentation, you can achieve what you desire. Be careful that there is some differences between FFmpeg's version in these examples and current FFmpeg's version. For example:
st = av_new_stream(oc, 1); // line 60
Could be replaced by:
st = avformat_new_stream(oc, NULL);
st->id = 1;
Or:
if (avcodec_open(c, codec) < 0) { // line 97
Could be replaced by:
if (avcodec_open2(c, codec, NULL) < 0) {
Or again:
dump_format(oc, 0, filename, 1); // line 483
Could be replaced by:
av_dump_format(oc, 0, filename, 1);
Or CODEC_ID_NONE by AV_CODEC_ID_NONE... etc.
Ask your questions, but you got all the keys! :)
MobileFFMpeg is an easy to use pod for the purpose. Instructions on how to use MobileFFMpeg at: https://stackoverflow.com/a/59325680/1466453
MobileFFMpeg gives a very simple method for translating ffmpeg commands to your IOS objective-c program.
Virtually all ffmpeg commands and switches are supported. However you have to get the pod with appropriate license. e.g min-gpl will not give you features of libiconv. libiconv is convered in vidoe, gpl and full-gpl licenses.
Please highlight if you have specific issues regarding use of MobileFFMpeg
import cv2
cap = cv2.VideoCapture("StopMoti2001.mpeg")
if cap.isOpened():
print 'fine'
else:
print 'not fine'
output is 'not fine' I have checked for various videos and I also moved the ffmpeg file moving to PATH and still the problem remains same. can you please suggest a solution
Solved my problem, Actually I was working in anaconda, so instead of moving ffmpeg to Python27, I should move it to Anaconda dll folder to make it work.
I am trying to run a very simple program. To open and jpg file and display it using the opencv library for python. Initially it all worked fine but now it just opens a window which doesn't show the image but says 'not responding'. I need to go to the task manager and close it!
from numpy import *
import matplotlib as plt
import cv2
img = cv2.imread('amandapeet.jpg')
print img.shape
cv2.imshow('Amanda', img)
You missed one more line:
cv2.waitKey(0)
Then the window shows the image until you press any key on keyboard. Or you can pass as following:
cv2.waitKey(1000)
cv2.destroyAllWindows()
Here, window shows image for 1000 ms, or 1 second. After that, the window would disappear itself. But in some cases, it won't. So you can forcefully destroy it using cv2.destroyAllWindows()
Please read more tutorials first : http://docs.opencv.org/trunk/doc/py_tutorials/py_tutorials.html
None of the answers here worked in MacOS. The following works:
Just add a cv2.waitKey(1) after cv2.destroyAllWindows().
Example:
import cv2
image = cv2.imread('my_image.jpg')
cv2.imshow('HSV image', hsv_image); cv2.waitKey(0); cv2.destroyAllWindows(); cv2.waitKey(1)
The solution that worked for me:
Switch from inline graphics to auto. It worked both in Spyder and in Jupyter notebooks.
To change Spyder setting:
Go to Tools > Preferences > IPhyton console > Graphics > Backend: Automatic
(Change backend from Inline to Automatic)
To change Notebook setting:
Enter command:
%matplotlib auto
Some background for my case (for those who may be quick to judge):
It used to work fine: I could open an image, it would load, and it would be responsive (doesn't say "Not responding", can close, focus, etc.) Then I installed some packages and ran some demo notebooks that apparently messed up some settings (Spyder open files were reset too).
I tried adding waitKey(1) (and 0, 30, 1000, etc values too). It made the image load, at least. But the image frame was "Not Responding": didn't refresh, couldn't close, didn't come to top, etc. Had to close using cv2.destroyAllWindows().
Note that everything worked fine during the duration of waitKey. I put this in a loop that shows the same image in the same named window and waits for a few seconds. During the loop everything works fine. As soon as the loop ends, the image window is "Not responding" (which looks like a GUI thread issue). I tried using cv2.startWindowThread(), and didn't make any difference.
Finally, changing from Inline graphics to Auto brought everything back to order.
I've been working with opencv 3.2 and matplotlib too recently and discovered (through trial and error of commenting out lines) that the import of pyplot from matplotlib has some sort of interference with the cv2.imshow() function. I'm not sure why or how it really works but in case anyone searches for this issue and comes across this old forum, this might help. I'm working to try to find a solution around this interference bu
I did also face the same issue. I am running through command line python prompt in centos 7 with the following code
>> import cv2, numpy as np
>> cap=cv2.VideoCapture(0)
>> img=cap.read()
>> cap.release()
>> cv2.imshow('image',img[1])
>> cv2.waitKey(0)
>> cv2.destroyAllWindows()
>> cv2.waitKey(1)
Even then the problem persisted and didn't solve. So I added
>> cv2.imshow('image',img[1])
Adding this did close the image window.Running the command again would create a new instance. Hope you can try if you still face any issues.
The cv2.imshow() function always takes two more functions to load and close the image. These two functions are cv2.waitKey() and cv2.destroyAllWindows(). Inside the cv2.waitKey() function, you can provide any value to close the image and continue with further lines of code.
# First line will provide resizing ability to the window
cv.namedWindow('Amanda', cv.WINDOW_AUTOSIZE)
# Show the image, note that the name of the output window must be same
cv.imshow('Amanda', img)
# T0 load and hold the image
cv.waitKey(0)
# To close the window after the required kill value was provided
cv.destroyAllWindows()
Hoping that you will get the image in a separate window now.
I've installed opencv-contrib-python library instead of opencv-python and now cv2.imshow() function works as expected.
If you have used python notebooks then there is a problem in using cv2.waitKey(0) and cv2.destroyallwindows() in Unix based system to run a program of opencv.
I have an alternative method which would prevent from freezing your image
Steps: -Copy the code from python notebooks and create new filename.py and paste it
- Open terminal
- cd path/to/file
- source activate VirtualEnvironment
- python filename.py
This will run code directly from terminal. Hope this helps you. Example Link: https://youtu.be/8O-FW4Wm10s
I was having this same error until I added the below lines of code. For the waitKey, you can input figures above 0(i.e 1, 100 and above). It serves as the delay time for the window and it is in milliseconds.
----> cv2 waitKey(0)
----> cv2 destroyAllWindows()
I found that i had a breakpoint on the
cv2.waitkey()
funtion. removing that fixed the issue for me
As I tried all solutions mentioned above, it works for displaying an image but in my case, I want to display the video not just the single image in the window, So to solve the problem added
k=cv2.waitkey(10)
if k == 27:
break
after cv2.imshow('title',img)
Recently I migrated to OpenCV 2.4.3 from OpenCV 2.4.1.
My program which worked well with 2.4.1 version now encounters problem with 2.4.3.
The problem is related to VideoCapture that can not open my video file.
I saw a similar problem while searching the internet, but I couldn't find a proper solution for this. Here is my sample code:
VideoCapture video(argv[1]);
while(video.grab())
{
video.retrieve(imgFrame);
imshow("Video",ImgFrame);
waitKey(1);
}
It's worth mentioning that capturing video from webcam device works well, but I want to grab stream from file.
I'm using QT Creator 5 and I compiled OpenCV with MinGW. I'm using Windows.
I tried several different video formats and I rebuilt OpenCV with and without ffmpeg, but the problem still persists.
Any idea how to solve the problem?
Try this:
VideoCapture video(argv[1]);
int delay = 1000.0/video.get(CV_CAP_PROP_FPS);
while(1)
{
if ( !video.read(ImgFrame)) break;
imshow("Video",ImgFrame);
waitKey(delay);
}
In my experience with OpenCV I struggled using IP cams until my mentor discovered how to get them to work, don't forget to plug your IP address in otherwise it won't work!
import cv2
import numpy as np
import urllib.request
# Sets up the webcam and connects to it and initalizes a variable we use for it
stream=urllib.request.urlopen('http://xx.x.x.xx/mjpg/video.mjpg')
bytes=b''
while True:
# Takes frames from the camera that we can use
bytes+=stream.read(16384)
a = bytes.find(b'\xff\xd8')
b = bytes.find(b'\xff\xd9')
if a!=-1 and b!=-1:
jpg = bytes[a:b+2]
bytes= bytes[b+2:]
frame = cv2.imdecode(np.fromstring(jpg, dtype=np.uint8),cv2.IMREAD_COLOR)
img = frame[0:400, 0:640] # Camera dimensions [0:WIDTH, 0:HEIGHT]
# Displays the final product
cv2.imshow('frame',frame)
cv2.imshow('img',img)
# Hit esc to kill
if cv2.waitKey(1) ==27:
exit(0)