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• Trying to get frame timestamp with ffmpeg from a RTSP camera

  12 juin 2022, par jaygzixst

  I'm trying to retrieve the timestamp of each frame of a camera using an rstp stream and them.
For recording I use the following command line and it's work :

  


  ffmpeg
-correct_ts_overflow 0
-probesize 1G
-analyzeduration 1G
-i rtsp://user:password@ip:port
-vcodec copy
-bsf:v h264_mp4toannexb
-bufsize 10M
-acodec copy
-f ssegment
-segment_list_flags live
-segment_atclocktime 1
-reset_timestamps 1
-write_empty_segments 1
-segment_time 15
-segment_list C:\Video\Delivery\ffmpeg\list.video
-segment_list_type csv
-strftime 1 "C:\Video\Delivery\ffmpeg\%%Y%%m%%d_%%H-%%M-%%S.ts"


  


  And for some utility I would like to be able to retrieve the timestamp of the machine when I receive a frame, so by searching a bit I found different post on '-mkvtimestamp_v2'. By trying it alone with the camera as if below :

  


  ffmpeg
-copyts ^
-correct_ts_overflow 0 ^
-probesize 1G ^
-analyzeduration 1G ^
-i rtsp://user:password@ip:port
-c copy
-pix_fmt yuv420p
-flush_packets 1
-vframes 10
-reset_timestamps 1
-timestamp now
-copyts
-f mkvtimestamp_v2 timestamp.txt
-vsync 0


  


  It works perfectly.

  


  But from the moment I try to record AND try to retrieve the timestamp simultaneously with the following command :

  


  ffmpeg
-use_wallclock_as_timestamps 1
-correct_ts_overflow 0
-probesize 1G
-analyzeduration 1G
-i rtsp://user:password@ip:port
-vcodec copy
-bsf:v h264_mp4toannexb
-bufsize 10M
-acodec copy
-f ssegment
-segment_list_flags live
-segment_atclocktime 1
-reset_timestamps 1
-write_empty_segments 1
-segment_time 15
-segment_list C:\Video\Delivery\ffmpeg\list.video
-segment_list_type csv
-strftime 1 "C:\Video\Delivery\ffmpeg\%%Y%%m%%d_%%H-%%M-%%S.ts"
-copyts
-vcodec copy
-flush_packets 1
-f mkvtimestamp_v2 log.txt
-vsync 0


  


  I get a lot of : Non-monotonous DTS in output stream 0:0 warning.
I also have on average one minute delay between the recorded timestamps, and the real timestamp.
And the first video recorded have a bugged timer on a video player like this : Here

  


  I've tried arranging the command in different orders but I get nothing conclusive...

  


  So if you have any idea that would be a big help !

  


  I work on Windows 10 and I use ffmpeg-3.4.1.

  


  Cordially,

  


  Jay

  


• Add animated overlay to video from camera

  22 juillet 2017, par Oleg Filimonov

  I need to overlay multiple images with animated position, alpha and rotation on recorded video. What’s the best way to accomplish this ?

  Currently I’m looking at ffmpeg, is it possible to add position animation to overlays using ffmpeg ?

• OpenCV Multi-camera handling issue

  19 janvier 2013, par user1797582

  1) I get this errors while handling two logitech c310 cameras with OpenCV(updated Kubuntu Linux)

  VIDIOC_STREAMON : No space left on device

  Whole error log is as below

  **IDIOC_QUERYMENU: Invalid argument
  
  VIDIOC_QUERYMENU: Invalid argument**
  
  VIDIOC_QUERYMENU: Invalid argument
  
  VIDIOC_QUERYMENU: Invalid argument
  
  VIDIOC_QUERYMENU: Invalid argument
  
  VIDIOC_QUERYMENU: Invalid argument
  
  VIDIOC_QUERYMENU: Invalid argument
  
  **libv4l2: error turning on stream: No space left on device**
  
  **VIDIOC_STREAMON: No space left on device**
  
  OpenCV Error: Bad flag (parameter or structure field) (Unrecognized or unsupported array type) in cvGetMat, file /home/rjdp/Computer_Vision/0_Installers/OpenCV-2.4.2/modules/core/src/array.cpp, line 2482
  
  terminate called after throwing an instance of 'cv::Exception'
  
    what():  /home/rjdp/Computer_Vision/0_Installers/OpenCV-2.4.2/modules/core/src/array.cpp:2482: error: (-206) Unrecognized or unsupported array type in function cvGetMat

  2) It happens only when Handling two cameras, Even at default low res 640x480. I still tried to lower resolution in code to 320x240 which also did not work.

  3) I searched in lot of other posts here & on other sites. Which told me there is not enough USB cam bandwidth available. So I tried to plug one cam in front USB & one in the back side which also failed :(

  My Question is :

  Is it possible to solve this issue of bandwith/memory & run two or
  more cameras together on opencv 2.4.2 ?? OpenCV uses ffmpeg to handle I/O so can i tell my camera hardware with some ffmpeg command to take input stream with compressed MPEG mode instead of bandwidth consuming normal mode.

  CODE IS AS BELOW :

  #include "opencv2/opencv.hpp"
  
  #include 
  
  using namespace cv;
  
  
  
  int main(int, char**)
  
  {
  
      VideoCapture cap01(0); // open the default camera
  
      cap01.set(CV_CAP_PROP_FRAME_WIDTH,320);
  
      cap01.set(CV_CAP_PROP_FRAME_HEIGHT,240);
  
      //sleep(1);
  
      if(!cap01.isOpened())  // check if we succeeded
  
          return -1;
  
      namedWindow("Camera01",1);
  
  
  
      VideoCapture cap02(1); // open the default camera
  
      cap02.set(CV_CAP_PROP_FRAME_WIDTH,320);
  
      cap02.set(CV_CAP_PROP_FRAME_HEIGHT,240);
  
     if(!cap02.isOpened())  // check if we succeeded
  
          return -1;
  
      namedWindow("Camera02",1);
  
  
  
      for(;;)
  
      {
  
          Mat frame, frame_1;
  
          //Mat frame02;
  
          cap02 >> frame;
  
          imshow("Camera01", frame);
  
          if(waitKey(30) >= 0) break;
  
          Mat frame_1;
  
          cap02 >> frame_1; 
  
          imshow("Camera02", frame_1);
  
          if(waitKey(30) >= 0) break;
  
      }
  
  
  
      return 0;
  
  }