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• Broadcast mjpeg stream via websocket using ffmpeg and Python Tornado

  25 février 2016, par Asampaiz

  Well, i have been strugling for weeks now. Searching and reading a hundred of pages and nearly surrender.

  I need your help, this is the story : I want to stream my Logitech C930e webcam (connected to Raspi 2) to web browser. I have tried so many different way, such as using ffserver to pass the stream from ffmpeg to the web browser, but all of that is using same basic, it’s all need a re-encoding. ffserver will always re-encode the stream that passed by ffmpeg, no matter it is already on the right format or not. My webcam have built-in video encoding to mjpeg until 1080p, so that is the reason why i use this webcam, i don’t want using all of Raspi 2 resource just for encoding those stream.

  This approach end up in eating all my Raspi 2 Resources.

  Logitech C930e ---mjpeg 720p (compressed) instead of rawvideo---> ffmjpeg (copy, no reencoding) —http—> ffserver(mjpeg, reencoding to mjpeg ;this is the problem) —http—> Firefox

  My new approach

  Logitech C930e ---mjpeg 720p (compressed) instead of rawvideo---> ffmjpeg (copy, no reencoding —pipe—> Python3 (using tornado as the web framework) —websocket—> Firefox

  The problem of the new approach

  The problem is i can not make sure the stream format that passed by ffmpeg via pipe to Python is ready | compatible to be streamed to browser via websocket. I mean i already do all these step above but the result is unreadable image shown in the browser (like TV lost signal).

  1. I need help figuring out how to feed python the right mjpeg stream format with ffmpeg
  2. I need help on the client side (javascript) how to show the binary message that sent via websocket (the mjpeg stream)

  This is my current script

  Executing ffmpeg in Python (pipe) - Server Side

  --- cut ---
  
          multiprocessing.Process.__init__(self)
  
          self.resultQ = resultQ
  
          self.taskQ = taskQ
  
          self.FFMPEG_BIN = "/home/pi/bin/ffmpeg"
  
          self.video_w = 1280
  
          self.video_h = 720
  
          self.video_res = '1280x720'
  
          self.webcam = '/dev/video0'
  
          self.frame_rate = '10'
  
          self.command = ''
  
          self.pipe = ''
  
          self.stdout = ''
  
          self.stderr = ''
  
  
  
      #Start the ffmpeg, this parameter need to be ajusted,
  
      #video format already tried rawvide, singlejpeg, mjpeg
  
      #mpjpeg, image2pipe
  
      #i need help here (to make sure the format is right for pipe)
  
      def camera_stream_start(self):
  
              self.command = [ self.FFMPEG_BIN,
  
                  '-loglevel', 'debug',
  
                  '-y', 
  
                  '-f', 'v4l2',
  
                  '-input_format', 'mjpeg',
  
                  '-s', self.video_res,
  
                  '-r', self.frame_rate,
  
                  '-i', self.webcam,
  
                  '-c:v', 'copy',
  
                  '-an', 
  
                  '-f', 'rawvideo',
  
                  #'-pix_fmts', 'rgb24',
  
                  '-']
  
              self.pipe = sp.Popen(self.command, stdin=sp.PIPE, stdout = sp.PIPE, shell=False)
  
              #return self.pipe
  
  
  
      #stop ffmpeg
  
      def camera_stream_stop(self):
  
          self.pipe.stdout.flush()
  
          self.pipe.terminate()
  
          self.pipe = ''
  
          #return self.pipe
  
  
  
      def run(self):
  
          #start stream
  
          self.camera_stream_start()
  
          logging.info("** Camera process started")
  
          while True:
  
              #get the stream from pipe,
  
              #this part is also need to be ajusted
  
              #i need help here
  
              #processing the stream read so it can be
  
              #send to browser via websocket
  
              stream = self.pipe.stdout.read(self.video_w*self.video_h*3)
  
  
  
              #reply format to main process
  
              #in main process, the data will be send over binary websocket
  
              #to client (self.write_message(data, binary=True))
  
              rpl = {
  
                  'task' : 'feed',
  
                  'is_binary': True,
  
                  'data' : stream
  
              }
  
              self.pipe.stdout.flush()
  
              self.resultQ.put(rpl)
  
              #add some wait
  
              time.sleep(0.01)
  
          self.camera_stream_stop()
  
          logging.info("** Camera process ended")

  ffmpeg output

  --- Cut ---     
  
  Successfully opened the file.
  
  Output #0, rawvideo, to 'pipe:':
  
    Metadata:
  
      encoder         : Lavf57.26.100
  
      Stream #0:0, 0, 1/10: Video: mjpeg, 1 reference frame, yuvj422p(center), 1280x720 (0x0), 1/10, q=2-31, -1 kb/s, 10 fps, 10 tbr, 10 tbn, 10 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
  Press [q] to stop, [?] for help
  
  --- Cut ---     

  JavaScript websocket - on the client side

  --- Cut ---
  
  socket = new WebSocket(url, protocols || []);
  
  socket.binaryType = "arraybuffer";
  
  
  
  socket.onmessage = function (message) {
  
      //log.debug(message.data instanceof ArrayBuffer);
  
      //This is for the stream that sent via websocket
  
      if(message.data instanceof ArrayBuffer)
  
      {
  
          //I need help here
  
          //How can i process the binary stream
  
          //so its can be shown in the browser (img)
  
          var bytearray = new Uint8Array(message.data);
  
          var imageheight = 720;
  
          var imagewidth = 1280;
  
  
  
          var tempcanvas = document.createElement('canvas');
  
          tempcanvas.height = imageheight;
  
          tempcanvas.width = imagewidth;
  
          var tempcontext = tempcanvas.getContext('2d');
  
  
  
          var imgdata = tempcontext.getImageData(0,0,imagewidth,imageheight);
  
  
  
          var imgdatalen = imgdata.data.length;
  
  
  
          for(var i=8;i/this is for ordinary string that sent via websocket
  
      else{
  
          pushData = JSON.parse(message.data);
  
          console.log(pushData);
  
      }
  
  
  
   --- Cut ---

  Any help, feedback or anything is very appreciated. If something not clear please advice me.

• FFMPEG : Video file to YUV conversion by binary ffmpeg and by code C++ give different results

  30 juin 2016, par Anny G

  Disclaimer : I have looked at the following question,
  FFMPEG : RGB to YUV conversion by binary ffmpeg and by code C++ give different results
  but it didn’t help and it is not applicable to me because I am not using SwsContext or anything.

  Following first few tutorials by http://dranger.com/ffmpeg/, I have created a simple program that reads a video, decodes it and then when the frame is decoded, it writes the raw yuv values to a file (no padding), using the data provided by AVFrame after we successfully decoded a frame. To be more specific, I write out arrays AVFrame->data[0], AVFrame->data[1] and AVFrame->data[2] to a file, i.e. I simply append Y values, then U values, then V values to a file. The file turns out to be of yuv422p format.

  When I convert the same original video to a raw yuv format using the ffmpeg(same version of ffmpeg) command line tool, the two yuv files are the same in size, but differ in content.

  FYI, I am able to play both of the yuv files using the yuv player, and they look identical as well.

  Here is the exact command I run to convert the original video to a yuv video using ffmpeg command line tool

   ~/bin/ffmpeg -i super-short-video.h264 -c:v rawvideo -pix_fmt yuv422p  "super-short-video-yuv422p.yuv"

  What causes this difference in bytes and can it be fixed ? Is there perhaps another way of converting the original video to a yuv using the ffmpeg tool but maybe I need to use different settings ?

  Ffmpeg output when I convert to a yuv format :

  ffmpeg version N-80002-g5afecff Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.1)
  
    configuration: --prefix=/home/me/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/home/me/ffmpeg_build/include --extra-ldflags=-L/home/me/ffmpeg_build/lib --bindir=/home/me/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree --extra-cflags=-pg --extra-ldflags=-pg --disable-stripping
  
    libavutil      55. 24.100 / 55. 24.100
  
    libavcodec     57. 42.100 / 57. 42.100
  
    libavformat    57. 36.100 / 57. 36.100
  
    libavdevice    57.  0.101 / 57.  0.101
  
    libavfilter     6. 45.100 /  6. 45.100
  
    libswscale      4.  1.100 /  4.  1.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, h264, from 'super-short-video.h264':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: h264 (High), yuv420p, 1280x720, 25 fps, 25 tbr, 1200k tbn
  
  [rawvideo @ 0x24f6fc0] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
  
  Output #0, rawvideo, to 'super-short-video-yuv422p.yuv':
  
    Metadata:
  
      encoder         : Lavf57.36.100
  
      Stream #0:0: Video: rawvideo (Y42B / 0x42323459), yuv422p, 1280x720, q=2-31, 200 kb/s, 25 fps, 25 tbn
  
      Metadata:
  
        encoder         : Lavc57.42.100 rawvideo
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> rawvideo (native))
  
  Press [q] to stop, [?] for help
  
  frame=   50 fps=0.0 q=-0.0 Lsize=   90000kB time=00:00:02.00 bitrate=368640.0kbits/s speed=11.3x    
  
  video:90000kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000%

• Compile ffmpeg and x264 with —enable-shared

  20 août 2016, par John Allard

  I am trying to compile ffmpeg with shared-library support, because when I compiled it statically it ended up making huge libraries, like libavcodec.a with 75MB in size. Any programs that I compiled against libavcodec was at least 50MB in size. This only happens on my RaspberryPi though, if I do

  ls -lsth $(which ffmpeg)

  on my RPI3 I get

  15M -rwxr-xr-x 1 pi pi 15M Jul 29 21:49 /home/pi/camiocam/cam/binaries/bin//ffmpeg

  While if I do the same on my macbook I get this output

  488 -r-xr-xr-x  1 john  admin   242K Jul 26 19:34 /usr/local/Cellar/ffmpeg/3.1.1/bin/ffmpeg

  To get shared library support I did the following

  # download and install libx264
  
  cd ~/ffmpeg_build
  
  git clone git://git.videolan.org/x264.git
  
  cd x264
  
  PATH="$HOME/bin:$PATH" ./configure --host=arm-unknown-linux-gnueabi  --prefix="$HOME/ffmpeg_build" --bindir="$HOME/bin" --enable-shared --disable-opencl
  
  # PATH="$HOME/bin:$PATH" make -j 8
  
  # PATH="$HOME/bin:$PATH" make install
  
  # ldconfig

  and ...

  # to install ffmpeg
  
  
  
  cd ~/ffmpeg_sources
  
  wget http://ffmpeg.org/releases/ffmpeg-snapshot.tar.bz2
  
  tar xjvf ffmpeg-snapshot.tar.bz2
  
  cd ffmpeg
  
  PATH="$HOME/bin:$PATH" PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure --prefix="$HOME/ffmpeg_build" --arch=armel --target-os=linux --extra-cflags="-I$HOME/ffmpeg_build/include" --enable-pic  --extra-ldflags="-L$HOME/ffmpeg_build/lib" --bindir="$HOME/bin" --enable-gpl --enable-libx264 --enable-nonfree --enable-shared
  
  PATH="$HOME/bin:$PATH" make -j 8

  Which gives this output

  License: nonfree and unredistributable
  
  Creating config.mak, config.h, and doc/config.texi...
  
  config.h is unchanged
  
  libavutil/avconfig.h is unchanged
  
  libavcodec/bsf_list.c is unchanged
  
  libavformat/protocol_list.c is unchanged
  
  CC      libavcodec/libx264.o
  
  POD     doc/ffprobe.pod
  
  POD     doc/ffmpeg-all.pod
  
  POD     doc/ffserver-all.pod
  
  POD     doc/ffmpeg.pod
  
  POD     doc/ffprobe-all.pod
  
  POD     doc/ffserver.pod
  
  MAN     doc/ffprobe.1
  
  MAN     doc/ffmpeg.1
  
  MAN     doc/ffserver.1
  
  MAN     doc/ffmpeg-all.1
  
  MAN     doc/ffprobe-all.1
  
  MAN     doc/ffserver-all.1
  
  GEN     libavcodec/libavcodec.ver
  
  LD      libavcodec/libavcodec.so.57
  
  AR      libavcodec/libavcodec.a
  
  LD      libavformat/libavformat.so.57
  
  LD      libavfilter/libavfilter.so.6
  
  LD      libavdevice/libavdevice.so.57
  
  library.mak:102: recipe for target 'libavdevice/libavdevice.so.57' failed
  
  make: *** [libavdevice/libavdevice.so.57] Killed
  
  make: *** Deleting file 'libavdevice/libavdevice.so.57'

  I’ve tried to add the --enable-pic flag to the ffmpeg configure command but that made no difference.