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• How to use ffmpeg to extract frames from video and read as a list of images in python in memory without writing files

  11 octobre 2020, par yiy

  At my application server, I have a stream of Webm chunks coming from browsers that users record live videos. I want to analyze each frame simultaneously. So I used python to create a generator yielding the Webm file binaries to feed into ffmpeg. I use the command python convert.py | ffmpeg -i pipe: -r 1 output%3d.jpg to create a set of frames files. (The convert.py is just the generator to yield binary webm data for ffmpeg).

  


  My question is that how can I make the ffmpeg output to a new pipe that in python I can read as a list of images directly ?

  


• avcodec/parser : move parsers list and related API to its own file

  21 juillet 2018, par James Almer

  avcodec/parser : move parsers list and related API to its own file
  And add it to the CONFIGURABLE_COMPONENTS list in Makefile. This way, changes
  
  to the new file will be tracked and the usual warning to suggest re-running
  
  configure will be shown.
  Reviewed-by : Rostislav Pehlivanov <atomnuker@gmail.com>
  
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] Makefile
  • [DH] configure
  • [DH] libavcodec/Makefile
  • [DH] libavcodec/parser.c
  • [DH] libavcodec/parsers.c

• Trim with transition/fade using FFMPEG given a list of timestamps

  19 janvier 2024, par realsarm

  I have a video and a list of timestamps that I want to filter.

  


  [
  {
    "timestamp": [10, 20],
    "state": true
  },
  {
    "timestamp": [30, 40],
    "state": false
  },
  {
    "timestamp": [50, 60],
    "state": true
  },
  {
    "timestamp": [70, 80],
    "state": true
  }
]


  


  I have a script like this to trim based on state.

  


      video_path = Path(video_in.name)
    video_file_name = video_path.stem

    timestamps_to_cut = [
        (timestamps_var[i]['timestamp'][0], timestamps_var[i]['timestamp'][1])
        for i in range(len(timestamps_var)) if timestamps_var[i]['state']]

    between_str = '+'.join(
        map(lambda t: f'between(t,{t[0]},{t[1]})', timestamps_to_cut))

    if timestamps_to_cut:
        video_file = ffmpeg.input(video_path)
        video = video_file.video.filter(
            "select", f'({between_str})').filter("setpts", "N/FRAME_RATE/TB")
        audio = video_file.audio.filter(
            "aselect", f'({between_str})').filter("asetpts", "N/SR/TB")

        output_video = f'./videos_out/{video_file_name}.mp4'
        ffmpeg.concat(video, audio, v=1, a=1).output(
            output_video).overwrite_output().global_args('-loglevel', 'quiet').run()


  


  How can I smooth out this trimming like adding a fade or smoothing transition each time state is false ?