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• How to run ffmpeg command from the client side ?

  12 janvier 2017, par Debraj Biswas

  I am trying to make an online examination portal. When students start the exam, their webcam will start automatically and record the stream live and store in the server. Invigilators will either watch the students live or they can watch the saved live streams later.

  After many research on various technologies I came across this link. It uses Node JS with websockets and ffmpeg. I ran the ffmpeg command and it streamed the live video successfully.

  But the problem is, in order to live stream, the students have to have ffmpeg installed in their system and they should run the command directly from the terminal. So how can I change this ? The students will live stream from their browser, because this is a web portal. If we put this command in a PHP script, then the command will run at the server side. But client side command should run in this case. How can I run command from client side ?

  Any suggestions will be helpful.

• Video Codec For Commercial Use [on hold]

  17 décembre 2015, par mFeinstein

  I am new in video programming and I need to make a commercial application that needs to export some video. I was going to use OpenCV, but the documentation says it can’t write a video larger than 2Gb and that’s not something that my project can tolerate.

  I have an industrial camera and I will receive each frame of the camera in my C++ code and I want to transform the frames in a video. So far I am thinking about using FFmpeg for the video generation, but I am afraid of all these patented codecs.

  Are there any codecs that are free for commercial use ?

  Edit :

  Some are flaging this post as not related to programing or opinion based.

  1. I am not asking for an opinion, but a list of commercial free codecs. I am not asking which are good or bad (which is opinion based) I just can’t find a list online.

  2. This is about programing, there are lots of posts here in SO about legal issues on software like licensing, there is even one with a "legal" tag. I found many posts related to codecs licenses but none with a list of free ones. Of course this is programing related, I will develop and architecture my code around my options.

• OpenCV VideoCapture can't read from stream

  18 décembre 2018, par Josep Valls

  I can open a stream in VLC but in OpenCV I cannot capture frames. (Python 2.7, OpenCV 3.4.3 binary distribution x86, Windows 10). I’ve been following this guide : https://medium.com/@tomgrek/hackers-guide-to-the-aws-deeplens-1b8281bc6e24 but I cannot seem to read from random streams online (not sure whether I should be able to, I saw this question opencv videocapture can’t open MJPEG stream about compiling with ffmpeg but I just downloaded the binary available in Sourceforge).

  • I am using an AWS Deeplens, updated to the latest version.

  • Installed ffmpeg, latest version.

  Then, in /etc/ffserver.conf I added :

  <stream>
  
  File "/opt/awscam/out/ch1_out.h264"
  
  VideoFrameRate 6
  
  VideoSize 320x240
  
  NoAudio
  
  </stream>
  
  
  
  <stream>
  
  File "/opt/awscam/out/ch2_out.mjpeg"
  
  VideoFrameRate 3
  
  VideoSize 640x480
  
  Format mjpeg
  
  NoAudio
  
  </stream>

  • I start ffserver -f /etc/ffserver.conf
  • On my Windows machine, I use WSL and open an SSH tunnel into the AWS Deeplens ssh -L 8090:localhost:8090 aws_cam@192.168.0.10
  • At this point, in my Windows machine I can open VLC and if I point to http://localhost:8090/camera.mjpeg I can see the stream from the camera.

  But if I run the following code :

  cam = cv2.VideoCapture("http://localhost:8090/camera.mjpeg")
  
  success, frame = cam.read()
  
  opened = cam.isOpened()
  
  success, frame, opened

  I get :

  False, None, False

  If I browse to http://localhost:8090/stat.html, I see :

  Available Streams
  
  Path    Served Conns     bytes  Format  Bit rate kbits/s    Video kbits/s   Codec   Audio kbits/s    Codec  Feed
  
  test1.mpg   0   0   mpeg    96  64  mpeg1video  32  mp2 feed1.ffm
  
  test.asf    0   0   asf_stream  320 256 msmpeg4 64  wmav2   feed1.ffm
  
  stat.html   17  42150   -   -   -       -   
  
  index.html  0   0   -   -   -       -   
  
  camera.h264 3   6805k   h264    0   0   libx264 0       /opt/awscam/out/ch1_out.h264
  
  camera.mjpeg    12  41073k  mjpeg   0   0   mjpeg   0       /opt/awscam/out/ch2_out.mjpeg

  And every time I call VideoCapture() I see how the number of Served for the camera.mjpeg stream increased by a 2 or 3 and the bytes, increases a few megabytes but I don’t see anything in OpenCV. I have not tried any other video device in my Windows 10 but I can read images no problem. I also tried a random stream online, also opens in VLC but not in OpenCV, tried this one : http://136.176.70.200/mjpg/video.mjpg

  Any ideas ?