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• WebM Semantic Video Demo

  18 août 2010, par noreply@blogger.com (John Luther)

  Brett Gaylor at WebMadeMovies has posted an HTML5 demo of popcorn.js, “a javascript library for manipulating open video on the web.” The demo plays a video while using semantic data in the video to trigger machine-translated subtitles, map lookups, Twitter feeds and other elements on the page. If you’re using a WebM-enabled browser the page serves a WebM video, otherwise it serves an Ogg or MP4 video depending on the browser’s capabilities.

  See Brett’s post or the popcorn.js wiki page for more info. You can also download the source from the Mozilla github repo.

  

• ffplay - how to have video and audio waveform [duplicate]

  19 février 2018, par francis

  This question already has an answer here :

  • ffplay / ffmpeg setup table with audio and video filters
    
    1 answer
    

  I’ve been trying out various commands trying to figure out how to have a stack of video and audio waveform according to : https://trac.ffmpeg.org/wiki/FancyFilteringExamples#waveform

  Video only :

  ffplay -i abc.mp4 -vf "split[a][b];[a]waveform=e=1,split=1[c];[c]crop=in_w:16:0:0,lutyuv=y=val:v=180[high]; [b][high]vstack=2"

  Audio only :

  ffplay -f lavfi 'amovie=april.flac,asplit=2[out1][a]; [a]showwaves=s=640x240[waves]; [waves] vstack[out0]'

  But there isn’t any that combines and shows the top half as video and bottom half as the audio waveform. Is it possible ?

• How to add new video files to HLS ?

  3 décembre 2022, par Nori

  I'm having trouble live streaming a video file that is constantly updated using HLS.

  


  Video files recorded by POST from the client are sent to the server.

  


  The server converts the received video to HLS (.m3u8 .ts).

  


  You can convert to .m3u8 and .ts with the following code.

  


  def to_m3u8(movie_path: Path):
    """
    Convert mp4 to m3u8.
    :param movie_path:
    :return: m3u8 file path
    """
    m3u8_path = movie_path.parent/f"{movie_path.stem}.m3u8"
    command = f"ffmpeg -i {movie_path} " \
              f"-c copy " \
              f"-f segment -segment_time_delta 0 " \
              f"-segment_list_type hls " \
              f"-movflags +faststart " \
              f"-preset ultrafast " \
              f"-hls_playlist_type event " \
              f"-hls_flags append_list " \
              f"-hls_list_size 10 " \
              f"-segment_list_size 0 " \
              f"-segment_list {m3u8_path} " \
              f"-segment_format mpegts " \
              f"{movie_path.parent}/segment_%03d.ts"

    logger.info(f"command: {command}")
    subprocess.run(command, shell=True)
    return m3u8_path


  


  I can see the .m3u8 .ts file being overwritten every time I receive POST data.

  


  But when I open the .m3u8 in VLC it plays a few seconds of video and then stops.

  


  .m3u8 file is like this.

  


  #EXTM3U
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-ALLOW-CACHE:YES
#EXT-X-TARGETDURATION:5
#EXTINF:4.660000,
segment_000.ts
#EXTINF:4.120000,
segment_001.ts
#EXTINF:0.160000,
segment_002.ts
#EXT-X-ENDLIST


  


  I thought #EXT-X-ENDLIST is don't need. So I remove the line. Below code.

  


      with open(m3u8_path, "r") as f:
        lines = f.readlines()
    with open(m3u8_path, "w") as f:
        for line in lines:
            if line.startswith("#EXT-X-ENDLIST") is False:
                f.write(line)


  


  How ever it can't streaming. It's behave like a movie file.

  


  How can I read the newly added files at any time ?

  


  Can it be handled by changing FFmpege options ?