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• How to Write to AVI with OpenCV Python on Windows 10

  29 juillet 2019, par Novak

  I want to write properly formed frames of video data to an AVI.

  All attempts fail.

  What I end up with, after long efforts of debugging, are *.avi files of non-zero length in the desired directory, which will not play with any of multiple video players already installed on my system.

  Please note : High quality answers will be COMPLETE and DETAIL oriented. In particular, questions about writing video with OpenCV tend to generate drive-by responses including little more than another four-letter code to stick in fourcc. Answers which do so without also telling me at a minimum what file extension to use, what file type it will generate, and why it is expected to work over what I give above are unhelpful.

  Here are the salient details of the system :

  Operating System : Windows 10
  Language : Python 3.7, with Anaconda 3
  OpenCV : 4.1.0

  Here Is What I Have Done/Tried :

  Installed FFMPEG as per this link, restarted Anaconda, and verified ffmpeg (ffmpeg -version) from within Anaconda, with the following result :

  ffmpeg version N-94396-g47b6ca0b02 Copyright (c) 2000-2019 the FFmpeg developers
  
  built with gcc 9.1.1 (GCC) 20190716
  
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt
  
  libavutil      56. 32.100 / 56. 32.100
  
  libavcodec     58. 55.100 / 58. 55.100
  
  libavformat    58. 30.100 / 58. 30.100
  
  libavdevice    58.  9.100 / 58.  9.100
  
  libavfilter     7. 58.100 /  7. 58.100
  
  libswscale      5.  6.100 /  5.  6.100
  
  libswresample   3.  6.100 /  3.  6.100
  
  libpostproc    55.  6.100 / 55.  6.100

  Multiple variations on the theme of :

  import cv2
  
  fourcc = cv2.VideoWriter_fourcc(*"DIVX")
  
  vidout = cv2.VideoWriter(baseDir + "videos\\foo.avi", fourcc, 30, (530, 476))
  
  
  
  for frame in frames:
  
      <do stuff="stuff" to="to" generate="generate" foo="foo">
  
      cv2.imshow("foo", foo)
  
      vidout.write(foo)
  
  vidout.release()
  
  </do>

  Verified shape, dtype, and general viability of output data with cv2.imshow("foo", foo)

  Results : Unplayable AVI files

• Real-time streaming of rawdata images to Android with FFMPEG

  29 juillet 2015, par Philies

  CONDITIONS

  I have an C++ server (Linux) and want to transmit rawdata images (RGB, 32bit) to an Android device in real-time.
  The server generates the rawdata images (with or without bitmap header) continuously every x miliseconds. Now, I want to put the rawdata images into a stream and transmit them without much delay to the Android client.

  I’ve chosen FFMPEG for this kind of job.

  The input for FFMPEG should be the rawdata images, which are generated just in time. The output should be an rtsp stream (h264 or is another format better ?).
  On client side I will play the stream with the Android MediaPlayer. That works for a RTSP url like rtsp ://184.72.239.149/vod/mp4:BigBuckBunny_115k.mov

  ---

  PREVIOUS APPROCH :

  I’ve installed FFMPEG on my server.

  Depending on this question : https://ffmpeg.org/pipermail/ffmpeg-user/2013-April/014617.html ... here is my FFMEG command :

  ffmpeg -an -f rawvideo -vcodec rawvideo -pix_fmt rgb32 -r 10 -i -vcodec libx264 -r 30 -tune zerolatency -preset ultrafast -bsf:v h264_mp4toannexb -f mpegts udp://192.168.1.20:1234

  Explanation of the parameters :

  • -an = ignore audio
  • -report = log file in current directory

  INPUT :

  • -f = rawvideo (video format)
  • -vcodec = rawvideo (video codec)
  • -pix_fmt = rgb32
  • -r = 10 (frame rate)

  OUTPUT :

  • -vcodec = libx264
  • -r = 30 (frame rate)
  • -bsf:v = h264_mp4toannexb
  • -f = mpegts udp ://192.168.1.20:1234

  ---

  C++ Server Code Snippet :

  /* -------  Get image rawdata from source ------- */
  
  ...
  
  /* -------  Create image header which fits to the image rawdata ------- */
  
  ...
  
  
  
  /* ------- Store the picture local (not necessary?) ------- */
  
  FILE *f;
  
  f = fopen("/home/philies/test.bmp","wb");
  
  
  
  //Write Bitmap Headers
  
  fwrite(&imageFileHeader,1,sizeof(imageFileHeader),f);
  
  fwrite(imageInfoHeader,1, imageInfoHeader,f);
  
  
  
  //Write Bitmap Rawdata
  
  fwrite(lastImage.GetBitmapRawData(),1,imageSize,f);
  
  
  
  
  
  —> ffmpeg ???

  ---

  PROBLEMS/QUESTIONS :

  1. How can I specify the rawvideo of the ffmpeg command respectively how can I specify my bitmap rawdata (with or without header ?) as the input of the FFMPEG ?

  2. Is the FFMPEG command correct ?

  If I fire the FFMPEG command in the terminal I get this error :

  vcodec : no such file or directory

  EDIT :
  In the first step, I will open the udp stream with the VLC player on my Android device. After that I will set up a FFserver to create a RTSP stream

• What would be the correct way to use Exec or Transcode ffmpeg in SRS version of Windows 5.0.128

  29 janvier 2023, par diegosn79

  i was doing tests in different ways, and i can't use the Exec or Transcode option, i highlight that I have copied the ffmpeg.exe in the objs folder.
These are the codes I tried, and I attach the log errors.

  


  exec {

enabled on;

publish ./objs/ffmpeg.exe -rtbufsize 10M -i rtmp://10.1.9.240/live/encoder  -vf scale=1080:720 -c:v libx264 -profile:v high -level 4.2 -preset fast -b:v 1500k -c:a aac -ac 2 -b:a 96k -f flv -y rtmp://10.1.9.240:1935/live/encoderlow/;

}


  


  LOGS

  


  [2023-01-04 10:05:46.410][WARN][1309][01568ctu][11] EXEC : Ignore error, code=3028(FFmpegFork)(Failed to fork FFmpeg trancoder process) :
process start : vfork process failed, cli=./objs/ffmpeg.exe -rtbufsize 10M -i rtmp ://10.1.9.240/live/encoder -vf scale=1080:720 -c:v libx264 -profile:v high -level 4.2 -preset fast -b:v 1500k -c:a aac -ac 2 -b:a 96k -f flv -y rtmp ://10.1.9.240:1935/live/encoderlow/
thread [1309][01568ctu] : do_cycle() [./src/app/srs_app_ng_exec.cpp:108][errno=11]
thread [1309][01568ctu] : start() [./src/app/srs_app_process.cpp:197][errno=11]

  


  transcode

  


      enabled     on;

    ffmpeg      ./objs/ffmpeg.exe;

    engine ff {

        enabled         on;

        vfilter {

        }

        vcodec          libx264;

        vthreads        4;

        vprofile        high;

        vpreset         fast;

        vbitrate        1500k;

        vparams {

        }

        acodec          libfdk_aac;

        aparams {

        }

        output          rtmp://127.0.0.1:[port]/[app]/[stream]_[engine]?vhost=[vhost];

    }

}


  


  LOGS

  


  [2023-01-04 11:04:45.295][WARN][1489][34r32764][11] Encoder : Ignore error, code=3028(FFmpegFork)(Failed to fork FFmpeg trancoder process) : ffmpeg start : vfork process failed, cli=./objs/ffmpeg.exe -f flv -i rtmp ://127.0.0.1:1935/live ?vhost=defaultVhost/encoder -vcodec libx264 -b:v 1500000 -threads 4 -profile:v high -preset fast -acodec libfdk_aac -f flv -y rtmp ://127.0.0.1:1935/live/encoder_ff ?vhost=defaultVhost 1 > ./objs/ffmpeg-encoder-defaultVhost-live-encoder-ff.log 2 > ./objs/ffmpeg-encoder-defaultVhost-live-encoder-ff.log
thread [1489][34r32764] : do_cycle() [./src/app/srs_app_encoder.cpp:117][errno=11]
thread [1489][34r32764] : start() [./src/app/srs_app_process.cpp:197][errno=11]