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• Opencv VideoCapture not streaming RTSP link and returns "no frame !"

  6 septembre 2023, par Asadullah Naeem

  I am trying to stream my HikVision IP camera throough python. I am using cv2.VideoCapture("rtsp_link") which works fine on my Laptop but when I try to run the same python script with same Opencv and FFmpeg version it gives me following error :

  


  Error :

  


  [h264 @ 000002124c7f9a40] missing picture in access unit with size 47
[h264 @ 000002124c7f9a40] no frame!


  


  I have so far tried to run this script on 5 computer devices but it gives the same error. I am using the following python script and my Opencv version is 4.6.0.66 and ffmpeg version 2022-06-20-git-56419428a8-essentials_build-www.gyan.dev :

  


  Python Script :

  


  import cv2

# RTSP stream URL
rtsp_url = "rtsp://username:password@ip_address:port/Streaming/Channels/501"

# Open the RTSP stream
cap = cv2.VideoCapture(rtsp_url)

# Check if the stream was successfully opened
if not cap.isOpened():
    print("Failed to open RTSP stream.")
    exit()

# Read and display frames from the stream
while True:
    # Read a frame from the stream
    ret, frame = cap.read()

    # Check if the frame was successfully read
    if not ret:
        print("Failed to read frame from RTSP stream.")
        break

    # Display the frame
    cv2.imshow("RTSP Stream", frame)

    # Exit if 'q' is pressed
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# Release the resources
cap.release()
cv2.destroyAllWindows()



  


  Update :

  


  Code runs on a laptop on both wifi and mobile internet (4G) but on other devices rtsp link is accessible only with mobile internet (4G).

  


• ffmpeg doesn't work when the script is launched by cron - No protocol specified, Cannot open display :0.0

  14 janvier 2024, par a k

  ffmpeg in my script doesn't work when the script is launched by cron of the root

  


  Error : No protocol specified, Cannot open display :0.0

  


  OS : Ubuntu 20.04

  


  #!/bin/bash
log=/var/log/log2/log2.txt

echo ______________ $(date) >> "$log"
echo "$""DISPLAY" "=      "  "$DISPLAY" >> "$log" ;
echo whoami '         ' $(whoami) >> "$log" 
echo pwd '            ' $(pwd) >> "$log" 
echo "$""USER" "=" '        ' "$USER" >> "$log"
echo PATH '           ' "$PATH" >> "$log"
echo which ffmpeg '   ' $(which ffmpeg)>> "$log" 
echo whereis ffmpeg ' ' $(whereis ffmpeg) >> "$log" 
echo "\nls -l /bin/* | grep ffmpeg" '        ' >> "$log"
ls -l /usr/bin/* | grep ffmpeg >> "$log"
echo "ls -l /var/log | grep log2" ' '>> "$log"
ls -l /var/log | grep log2 >> "$log"

ffmpeg -y -f x11grab -s 1366x768 -i :0.0 -r 25 /var/log/log2/test.mp4 -loglevel error 2>>"$log" &

echo "pid ffmpeg ""$""!"" = " "$!" >> "$log" 
sleep 5
kill "$!"
echo exit >> "$log"
exit


  


  When Cron (Cron of the root) launches the script, ffmpeg shows the error "No protocol specified, Cannot open display :0.0"

  


  /var/log/log2/log2.txt :

  


  ______________ ven. 05 mai 2023 04:10:01 CEST
$DISPLAY =       
whoami           root
pwd              /root
$USER =          
PATH             /usr/bin:/bin
which ffmpeg     /usr/bin/ffmpeg
whereis ffmpeg   ffmpeg: /usr/bin/ffmpeg /usr/share/ffmpeg /usr/share/man/man1/ffmpeg.1.gz
ls -l /usr/bin/* | grep ffmpeg  
-rwxr-xr-x 1 root   root      284976 mai   18  2022 /usr/bin/ffmpeg
ls -l /var/log | grep log2  
drwxrwxrwx  2 root              root               4096 mai    5 04:09 log2
pid ffmpeg $! =  74590
No protocol specified
[x11grab @ 0x56244aa06740] Cannot open display :0.0, error 1.
:0.0: Input/output error
exit


  


  When I launch the script manually as a not-root user (with sudo), everything work correctly :

  


  ______________ ven. 05 mai 2023 04:10:47 CEST
$DISPLAY =       :0
whoami           root
pwd              /home/an
$USER =          root
PATH             /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin
which ffmpeg     /usr/bin/ffmpeg
whereis ffmpeg   ffmpeg: /usr/bin/ffmpeg /usr/share/ffmpeg /usr/share/man/man1/ffmpeg.1.gz
ls -l /usr/bin/* | grep ffmpeg  
-rwxr-xr-x 1 root   root      284976 mai   18  2022 /usr/bin/ffmpeg
ls -l /var/log | grep log2  
drwxrwxrwx  2 root              root               4096 mai    5 04:09 log2
pid ffmpeg $! =  74618
exit


  


  When I launch the script manually as the root, everything works correctly :

  


  ______________ ven. 05 mai 2023 04:11:27 CEST
$DISPLAY =       :0
whoami           root
pwd              /root
$USER =          root
PATH             /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin
which ffmpeg     /usr/bin/ffmpeg
whereis ffmpeg   ffmpeg: /usr/bin/ffmpeg /usr/share/ffmpeg /usr/share/man/man1/ffmpeg.1.gz
ls -l /usr/bin/* | grep ffmpeg  
-rwxr-xr-x 1 root   root      284976 mai   18  2022 /usr/bin/ffmpeg
ls -l /var/log | grep log2  
drwxrwxrwx  2 root              root               4096 mai    5 04:11 log2
pid ffmpeg $! =  74683
exit


  


  When crontab of an ordinary user launches the script, it works correctly :

  


  $DISPLAY =       
whoami           an
pwd              /home/an
$USER =          
PATH             /usr/bin:/bin
which ffmpeg     /usr/bin/ffmpeg
whereis ffmpeg   ffmpeg: /usr/bin/ffmpeg /usr/share/ffmpeg /usr/share/man/man1/ffmpeg.1.gz
ls -l /usr/bin/* | grep ffmpeg  
-rwxr-xr-x 1 root   root      284976 mai   18  2022 /usr/bin/ffmpeg
ls -l /var/log | grep log2  
drwxrwxrwx  2 root              root               4096 mai    5 05:05 log2
pid ffmpeg $! =  77601
exit


  


  I have tried to put into the script :

  


  export DISPLAY=":0"

  


  export DISPLAY=":0.0"

  


  export DISPLAY=":1"

  


• Gstreamer missing Decoder meta/x-gst-fourcc-mebx

  27 juin 2024, par ZZak

  I'm currently working with GStreamer in a Linux environment and encountered an issue after upgrading from GStreamer 1.18 to 1.22. While trying to process a video file, I received the following error message :

  


  [hevc @ 0x7f26101eba00] Skipping NAL unit 62 
[hevc @ 0x7f26100fcd40] Skipping NAL unit 62 
[hevc @ 0x7f2610113e00] Skipping NAL unit 62 
missing-plugin, type=(string)decoder, detail=(GstCaps)meta/x-gst-fourcc-mebx, name=(string)"meta/x-gst-fourcc-mebx\ decoder";



  


  Also discoverer gives
Missing plugins (gstreamer|1.0|gst-discoverer-1.0|meta/x-gst-fourcc-mebx decoder|decoder-meta/x-gst-fourcc-mebx)

  


  Source video is with .MOV video(made by iPhone) with I420_10LE format and not corrupted.
Also it's data (streams) :

  


   Stream #0:0(und): Video: hevc (Main 10) (hvc1 / 0x31637668), yuv420p10le(tv, bt2020nc/bt2020/arib-std-b67), 1920x1080, 8455 kb/s, 29.97 fps, 29.97 tbr, 600 tbn, 600 tbc (default)
    Metadata:
      rotate          : 90
      creation_time   : 2022-02-12T07:53:40.000000Z
      handler_name    : Core Media Video
      vendor_id       : [0][0][0][0]
      encoder         : HEVC
    Side data:
      DOVI configuration record: version: 1.0, profile: 8, level: 4, rpu flag: 1, el flag: 0, bl flag: 1, compatibility id: 4
      displaymatrix: rotation of -90.00 degrees
  Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 181 kb/s (default)
    Metadata:
      creation_time   : 2022-02-12T07:53:40.000000Z
      handler_name    : Core Media Audio
      vendor_id       : [0][0][0][0]
  Stream #0:2(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
    Metadata:
      creation_time   : 2022-02-12T07:53:40.000000Z
      handler_name    : Core Media Metadata
  Stream #0:3(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
    Metadata:
      creation_time   : 2022-02-12T07:53:40.000000Z
      handler_name    : Core Media Metadata
  Stream #0:4(und): Data: none (mebx / 0x7862656D), 34 kb/s (default)
    Metadata:
      creation_time   : 2022-02-12T07:53:40.000000Z



  


  This suggests that a GStreamer plugin with a decoder for the MIME type meta/x-gst-fourcc-mebx is missing from my environment. I didn't face this issue with version 1.18, but it started occurring after the upgrade to 1.22.
I've tried searching for information about this specific decoder, but I haven't been able to find any relevant details.
Could you please provide any insights or guidance on how to handle this MIME type, or which plugin should be installed to provide the necessary decoder ? If this decoder is part of a proprietary plugin or requires a specific setup, any information on how to proceed would be greatly appreciated.
Thank you for your time and help !