Sur d’autres sites (10993)

• Unable to send image to ffmpeg stdin from QProcess

  4 décembre 2019, par Go0od

  It not writing png file. I want to save central widget to png file. I have 2 files, one is main file and second one is ui file. Link has ui file.

  Getting error code :

  QWindowsPipeWriter::write failed. (The handle is invalid.)

  main.py

  import sys
  
  from PyQt5.QtWidgets import QWidget
  
  from PyQt5 import QtCore, QtGui, QtWidgets
  
  from green import Ui_MainWindow
  
  class MyWindow(QtWidgets.QMainWindow, Ui_MainWindow, QWidget):
  
     def __init__(self):
  
      QtWidgets.QMainWindow.__init__(self)
  
      Ui_MainWindow.__init__(self)
  
  
  
      self.setupUi(self)
  
      self.widger_screen()
  
  
  
  def widger_screen(self):
  
  
  
      self.process = QtCore.QProcess(app)
  
      self.process.setProcessChannelMode(self.process.ForwardedChannels)
  
      self.process.setOpenMode(self.process.WriteOnly)
  
      self.process.start('ffmpeg',
  
                         ['-y',
  
                          '-analyzeduration', '1000',
  
                          '-vcodec', 'png', '-i', '-',
  
                          '-vcodec', 'mpeg4',
  
                          '-qscale', '5', '-r', '24', 'video.avi',
  
                          "-loglevel", "debug"])
  
      for i in range(100):
  
          QWidget.grab(self.centralwidget).save(self.process, "PNG")
  
  
  
  if __name__ == '__main__':
  
  app = QtWidgets.QApplication(sys.argv)
  
  window = MyWindow()
  
  window.show()
  
  sys.exit(app.exec_())

  green.ui
  https://paste.pythondiscord.com/ugorifokiq.py

• Create a mkv file with colored background and containing a given audio and subtitle stream

  25 mai 2023, par rdrg109

  Table of contents

  


  

  • The context

  


  • Minimal working example

  


  • What I've tried

    

    • Create a mkv file with colored background and an audio stream

    


    • Create a mkv file with colored background, an audio stream and a subtitles stream

    


    


  


  • The question

  


  


  


  The context

  


  I have a *.flac file and a *.srt file. I want to merge those files in a MKV file, but at the same time, I want to add a video stream. I want the video stream to show a green background the entire time.

  


  


  Minimal working example

  


  For our experimentation, let's create two sample files : one *.flac file and one *.srt file.

  


  The following command creates a *.flac file that lasts 60 seconds and contains a sine wave.

  


  $ ffmpeg -y -f lavfi -i "sine=f=1000:d=60" input.flac


  


  The following command creates a *.srt file. Note that our last subtitle lasts until the sixth second, this is intended.

  


  $ cat << EOF > input.srt
1
00:00:00,000 --> 00:00:03,000
This is the first subtitle in a
SRT file.

2
00:00:03,000 --> 00:00:06,000
This is the second subtitle in a
SRT file.
EOF


  


  


  What I've tried

  


  


  Create a mkv file with colored background and an audio stream

  


  I know how to create a MKV file containing a given audio stream and a colored background as the video stream.

  


  The following command creates a MKV file containing input.flac as the audio stream and green background as the video stream. The MKV file have the same duration as input.flac.

  


  $ ffmpeg \
  -y \
  -f lavfi \
  -i color=c=green:s=2x2 \
  -i input.flac \
  -c:v libx264 \
  -c:a copy \
  -shortest \
  output.mkv


  


  The following command shows the duration of the streams in the resulting file.

  


  $ ffprobe -v error -print_format json -show_entries stream=codec_type:stream_tags=duration output.mkv | jq -r ''


  


  {
  "programs": [],
  "streams": [
    {
      "codec_type": "video",
      "tags": {
        "DURATION": "00:00:58.200000000"
      }
    },
    {
      "codec_type": "audio",
      "tags": {
        "DURATION": "00:01:00.000000000"
      }
    }
  ]
}


  


  


  Create a mkv file with colored background, an audio stream and a subtitles stream

  


  To add a subtitles stream, I just need to specify the *.srt file. However, when I do this, the duration of the video is set to the time of the last subtitle in the *.srt file. This is expected because I have used -shortest. I would get the result I'm looking for if it were possible to specify the stream that -shortest gives top priority to. I haven't found this information on the Internet.

  


  $ ffmpeg \
  -y \
  -f lavfi \
  -i color=c=green:s=2x2 \
  -i input.flac \
  -i input.srt \
  -c:v libx264 \
  -c:a copy \
  -shortest \
  output.mkv


  


  The following command shows the duration of the streams in the resulting file. Note that the maximum duration of the resulting file is 6 seconds, while in the resulting file from the previous section it was 1 minute.

  


  $ ffprobe -v error -print_format json -show_entries stream=codec_type:stream_tags=duration output.mkv | jq -r ''


  


  {
  "programs": [],
  "streams": [
    {
      "codec_type": "video",
      "tags": {
        "DURATION": "00:00:01.160000000"
      }
    },
    {
      "codec_type": "audio",
      "tags": {
        "DURATION": "00:00:03.134000000"
      }
    },
    {
      "codec_type": "subtitle",
      "tags": {
        "DURATION": "00:00:06.000000000"
      }
    }
  ]
}


  


  


  The question

  


  Given a *.flac file and a *.srt file. How to merge them in a *.mkv file so that it has the *.flac file as the audio stream, the *.srt file as the subtitles stream and a green background as the video stream ?

  


• AVFrame / AVPicture change color component

  26 avril 2014, par RoeeL

  Given a video stream (runs with SDL), I need to somehow make the video’s frames color green only, blue only and red only (depends on input).

  How can I do that ? How can I set the color component to be RED only for instance ? (R = 255, G = 0, B = 0)

  Didn’t manage to find anything on google. would love to get some assistance.

  thanks