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• How to enable hardware support for H.264 encoding on raspberry Pi 4B

  24 mars 2021, par MSD Paul

  I am trying to enable the hardware support for H264 encoding on raspberry pi 4B model. Compiling FFmpeg source enabling the configurations

  



  sudo ./configure --arch=armel --target-os=linux --enable-gpl --enable-omx --enable-omx-rpi --enable-nonfree


  



  following the link, https://github.com/legotheboss/YouTube-files/wiki/(RPi)-Compile-FFmpeg-with-the-OpenMAX-H.264-GPU-acceleration

  



  but while executing the encoding command after building and installing the ffmpeg with those configuration properly, I am getting the following error

  



  [h264_omx @ 0x156b6e0] Using OMX.broadcom.video_encode
[h264_omx @ 0x156b6e0] OMX error 80001000
[h264_omx @ 0x156b6e0] err 80001018 (-2147479528) on line 561
Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
Conversion failed!


  



  command used :

  



  ffmpeg -i /media/pi/pic_1_org.png -c:v h264_omx -c:a copy -b:v 1500k outputfile.mp4


  



  I just want to encode a single 4K image into a .mp4 file using H.264 encoder. 
Please let me know how to resolve this issue ?

  


• "Missing reference picture" error when saving rtsp stream with ffmpeg

  4 mars 2020, par Cédric Kamermans

  I want to record 10 seconds of video with an IP camera via ffmpeg. The output video looks fine but i get a bunch of "Missing reference picture" errors in the log. This only happens in the beginning of the process. I also get the warning "circular_buffer_size is not supported on this build".

  I started of with the following code :

  -y -i rtsp://username:password@IP:88/videoMain -t 10 ffmpeg_capture.mp4

  But this resulted in the output being corrupted in the beginning.
  I found the following code on a forum and this seems to fix that problem. The errors still remain though.

  -y -i rtsp://username:password@IP:88/videoMain -b 900k -vcodec copy -r 60 -t 10 ffmpeg_capture.mp4

  One thing to note is that currently we’re using a C2 V3 IP camera. This model is just for testing, we will upgrade to a better model when we get this working.

  I want to clarify that i’m just beginning to use ffmpeg, so I don’t quite understand it yet. It would be greatly appreciated if someone could provide an example code of how I can fix this problem.

  Thanks in advance !

• Video size optimization

  21 janvier 2020, par Heba Gamal Eldin

  I’m working on a task that should optimize the video’s size before uploading to the server in a web application.
  So i want my model to automatically optimize each input video size.

  I have many trials in different approaches like FFmpeg :
  I used libx265, h264 and lib265 as a codec, with some videos it increases the video size and others minimize it with little ratio and it takes so long to generate the output file.

  for example with video of size 8M

  input = {input_name: None}
  
  output = {output_name: '-n preset faster -vcodec libx265 -crf 28'} 

  The output file is 10M.

  And also tried OpenCV :
  But the output videos aren’t written the file appears 0kb size.

  ex : with input video resolution (1280×544)
  I want to down scale it by :

  cap= cv2.VideoCapture(file_name)
  
  cap.set(3,640)
  
  cap.set(4,480)
  
  codec = cv2.VideoWriter_fourcc(*'XDIV')
  
  out = cv2.VideoWriter(output_file, codec, 28.0 , (640,480))
  
  While cap.isOpened():
  
     bol, frame = cap.read()
  
     out.write(frame)
  
     cv2.imshow('video', frame)

  I become little bit confused. what are the parameters of the input,output videos i should consider to be optimized and make a vital size change in each specific video ? Is it the codec, width, height only ?

  What is the most effective approach to do this ?

  Should i build a predictive model for estimating the suitable output video file parameters or there is a method that auto adjust ?

  if there’s an illustrative example please provide me.