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• How can I open a program using PYTHON with Mutliprocessing, and send it strings from the main process ?

  12 février 2018, par Just Askin

  I have a program that sends frames as strings to FFMPEG using something similar to :

  Working script that streams without using multiprocessing module currently on Ubuntu

  #!/usr/bin/python
  
  import sys, os
  
  import subprocess as sp
  
  import pygame
  
  from pygame.locals import QUIT, KEYUP, K_ESCAPE
  
  import pygame.display
  
  
  
  pygame.init()
  
  os.environ['SDL_VIDEODRIVER'] = 'dummy'
  
  pygame.display.init()
  
  Display_Surface = pygame.display.set_mode([1280,720], 0, 32)
  
  
  
  # FFMPEG command and settings
  
  command = ['ffmpeg', '-framerate', '25', '-s', '1280x720', '-pix_fmt', 'rgba', '-f', 'rawvideo', '-i', '-',
  
             '-f', 'lavfi', '-i', 'anullsrc=cl=mono',
  
             '-pix_fmt', 'yuv420p','-s', 'hd720', '-r', '25', '-g', '50',
  
             '-f', 'flv', 'rtmp://a.rtmp.youtube.com/live2/xxxx-xxxx-xxxx-xxxx']
  
  
  
  pipe = sp.Popen(command, bufsize=0, stdin=sp.PIPE)
  
  
  
  while True:
  
      # Quit event handling
  
      for event in pygame.event.get():
  
          if event.type == QUIT or (event.type == KEYUP and event.key == K_ESCAPE):
  
              pygame.quit()
  
              sys.exit()
  
  
  
      pipe.stdin.write(pygame.image.tostring(Display_Surface, "RGBA"))
  
  
  
  pipe.stdin.close()
  
  pygame.display.quit()
  
  os._exit()

  This works fine, except for the fact that it is killing my CPU, which in turn causes my live stream to freeze often. The stupid GIL won’t let FFMPEG run on another CPU/Core while I have 3 perfectly good cores doing nothing.

  I just whipped up some code to open FFMPEG in another process. (By the way, I’m familiar with threading.Thread, but not Multiprocessing).

  import os
  
  import subprocess as sp
  
  import multiprocessing
  
  
  
  class FFMPEG_Consumer():
  
  
  
      def __init__(self):
  
          proc = multiprocessing.Process(target=self.start_ffmpeg)
  
          proc.start()
  
  
  
      def start_ffmpeg(self):
  
          command = ['ffmpeg','-pix_fmt', 'rgba', '-f', 'rawvideo', '-i', '-',
  
                     '-f, 'lavfi', '-i', 'anullsrc=channel_layout=stereo:sample_rate=44100',
  
                     '-pix_fmt', 'yuv420p','-s', 'hd720', '-f', 'flv', 'rtmp://example.com']
  
  
  
          pipe = sp.Popen(command, bufsize=-1, stdin=sp.PIPE)
  
  
  
      def send_down_the_pipe(self, frame):
  
          pipe.stdin.write(frame)
  
  
  
  ffmpeg = FFMPEG_Consumer()

  For anyone that knows how to use multiprocessing, I’m sure you will immediately see that this does not work because I can’t share variables this way across processes. But, it does open FFMPEG on another core.

  Most online tutorials and resources focus creating pools of workers and queues to send those workers something to be processed until a job is finished. I am however trying to send a new string repeatedly to FFMPEG through each iteration.

  How can I pipe my string to that process/instance of FFMPEG ?

  Or is what I’m trying to do not possible ?

  This was the working solution (with dumbed down FFMPEG settings) :

  #!/usr/bin/python
  
  import sys, os, multiprocessing
  
  import subprocess as sp
  
  import pygame
  
  from pygame.locals import QUIT, KEYUP, K_ESCAPE
  
  import pygame.display
  
  
  
  pygame.init()
  
  os.environ['SDL_VIDEODRIVER'] = 'dummy'
  
  pygame.display.init()
  
  Display_Surface = pygame.display.set_mode([1280,720], 0, 32)
  
  
  
  class FFMPEGConsumer(object):
  
      def __init__(self):
  
          self._r, self._w = multiprocessing.Pipe()
  
          self.reader = os.fdopen(self._r.fileno(), 'r')
  
          self.writer = os.fdopen(self._w.fileno(), 'w', 0)
  
          self.proc = None
  
  
  
      def start_ffmpeg(self):
  
  
  
          command = ['ffmpeg', '-framerate', '25', '-s', '1280x720', '-pix_fmt', 'rgba', '-f', 'rawvideo', '-i', '-',
  
             '-f', 'lavfi', '-i', 'anullsrc=cl=mono',
  
             '-pix_fmt', 'yuv420p','-s', 'hd720', '-r', '25', '-g', '50',
  
             '-f', 'flv', 'rtmp://a.rtmp.youtube.com/live2/xxxx-xxxx-xxxx-xxxx']
  
  
  
          self.proc = sp.Popen(command, bufsize=-1, stdin=self.reader)
  
  
  
      def send_down_the_pipe(self, frame):
  
          self.writer.write(frame)
  
          #print self._stdin.read()
  
  
  
      def __del__(self):
  
          self.reader.close()
  
          self.writer.close()
  
  
  
  ffmpeg = FFMPEGConsumer()
  
  
  
  while True:
  
      # Quit event handling
  
      for event in pygame.event.get():
  
          if event.type == QUIT or (event.type == KEYUP and event.key == K_ESCAPE):
  
              pygame.quit()
  
              sys.exit()
  
  
  
      ffmpeg.send_down_the_pipe(pygame.image.tostring(Display_Surface, "RGBA"))
  
      proc.join()
  
  
  
  pipe.stdin.close()
  
  pygame.display.quit()
  
  os._exit()

  All cores are firing and no lags so far !!!

• avformat/wavdec : Consider AV_INPUT_BUFFER_PADDING_SIZE in set_spdif()

  24 novembre 2020, par Michael Niedermayer

  avformat/wavdec : Consider AV_INPUT_BUFFER_PADDING_SIZE in set_spdif()
  The buffer is read by using the bit reader
  
  Fixes : out of array read
  
  Fixes : 27539/clusterfuzz-testcase-minimized-ffmpeg_dem_WAV_fuzzer-5650565572591616
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/wavdec.c

• How to show a watermark for 3 second on a MP4 using FFmpeg

  6 février 2014, par b1izzard

  I need to add a 3-second watermark to a Camera recorded video in Android. I'm using FFmpeg static build to execute the commands.

  Approach I

  I had tried the below command using latest version of FFmpeg(version N-60108-gda25a65) in my Desktop running Linux Mint, the command works fine.

  ffmpeg -y -itsoffset 3 -i input.mp4 -i myImage.jpg -filter_complex "[0:v][1:v]overlay=0:0:enable=between(t\,0\,3)"  -codec:a copy output.mp4

  In Android I'm using the FFmpegv1.2 with below config to execute the command.

   *******Starting FFMPEG
  
      ***ffmpeg version 1.2 Copyright (c) 2000-2013 the FFmpeg developers***
  
      ***  built on Mar 31 2013 23:44:57 with gcc 4.6 (GCC) 20120106 (prerelease)***
  
      ***  configuration: --arch=arm --target-os=linux --enable-runtime-cpudetect --enable-pic --disable-shared --enable-static --cross-prefix=/opt/android-ndk-r8e/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/arm-linux-androideabi- --sysroot=/opt/android-ndk-r8e/platforms/android-8/arch-arm --extra-cflags='-march=armv6' --extra-ldflags= --enable-ffmpeg --disable-ffplay --disable-ffprobe --disable-ffserver --disable-network***
  
      ***  libavutil      52. 18.100 / 52. 18.100***
  
      ***  libavcodec     54. 92.100 / 54. 92.100***
  
      ***  libavformat    54. 63.104 / 54. 63.104***
  
      ***  libavdevice    54.  3.103 / 54.  3.103***
  
      ***  libavfilter     3. 42.103 /  3. 42.103***
  
      ***  libswscale      2.  2.100 /  2.  2.100***
  
      ***  libswresample   0. 17.102 /  0. 17.102***

  Java Code to run the FFmpeg command :

  String[] ffmpegCommandToAddWatermark = { 
  
              mFfmpegInstallPath, "-y", "-itsoffset","3",
  
               "-i", INPUT_VIDEO_PATH, "-i", WATERMARK_IMAGE_PATH,
  
               "-filter_complex","[0:v][1:v]overlay=0:0:between(t\\,0\\,3)",
  
               "-strict","-2",
  
               "-codec:a","copy",OUTPUT_VIDEO_PATH};          
  
          try {
  
          Process ffmpegProcess = new ProcessBuilder(ffmpegCommandToAddWatermark)
  
              .redirectErrorStream(true).start();
  
  
  
          String line;
  
  
  
          BufferedReader reader = new BufferedReader(
  
              new InputStreamReader(ffmpegProcess.getInputStream()));
  
          Log.d(TAG, "*******Starting FFMPEG");
  
          while ((line = reader.readLine()) != null ) {
  
  
  
              Log.d(TAG, "***" + line + "***");
  
          }
  
          Log.d(null, "****ending FFMPEG****");
  
  
  
          } catch (Exception e) {
  
          e.printStackTrace();
  
          }

  The command execution failed with following error :

  ***[overlay @ 0x271f770] No option name near 'between(t,0,3)'***
  
  ***[AVFilterGraph @ 0x2711530] Error initializing filter 'overlay' with args '0:0:between(t,0,3)'***
  
  ***Error configuring filters.***

  The same command executes successfully when :enable=between(t\,0\,3) is removed, but the resulting output video has the watermark throughout the timeline, but I need watermark only for the starting 3 seconds.

  Approach II :

  I tried to convert WaterMarkImage to WaterMarkVideo

  ffmpeg -y -loop 1 -r 30 -i WaterMarkImage.jpg -b:v "4096k" -vf "scale=640:480" -t 3 WaterMarkVideo.mp4

  And then merge the WaterMarkVideo.mp4+CameraRecordedVideo.mp4 using the concat command :

  ffmpeg -y -f concat -i inputs.txt -c copy output.mp4

  The resulting output is corrupt due to BitRate,FrameRate,etc., mismatch. Any idea to solve the problem ?.