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• How to properly abort av_seek_frame on FFmpeg ?

  5 mars 2021, par SuRGeoNix

  Normally, you wouldn't care aborting av_seek_frame as it would be really fast on a local file. However, in my case I use a custom AVIOContext for torrent streaming with custom read/seek functions and I'm not able to abort a single seek request !

  


  I've already tried interrupt callbacks (they will not be called at all), some timeouts (rw_timeout/timeout etc.) but by checking FFmpeg's code didn't find anything at all. My last chance was to try to return on read/seek functions an error (I've tried AVERROR_EXIT) which causes even more problems (memory leaks).

  


  The main issue is with Matroska formats that they need to resync (level-1) and they are trying to scan the whole file.

  


  Unfortunately, I'm using C# .NET with FFmpeg.Autogen bindings which means that I don't have low-level access to play around. My workaround is to re-open the whole format context in case on seek abort (to ensure that the player will continues to play at least)

  


  Hope you have a tip for me !

  


  (By the way for some http/hls web formats interrupt callbacks are supported)

  


• ffmpeg - How to estimate CRF for h264 video target size

  10 septembre 2022, par the_RR

  According to the x264 encode documentation, in the CRF topic, it is informed that for every 6 additional points, the file size is reduced by approximately 50%.

  


  From this statement, it is assumed that the CRF has an exponential influence in reducing the final size of the video. But what is the exponential ratio ?

  


  I wouldn't want to use CRF18 with max-rate adjusted to reach a final size, as maxrate damage complex video scenes more strongly, as bitrate reduction via max_rate is not uniform, but it hits the scenes that require the highest bitrate first.

  


• moviepy ruining video after combining them

  1er juin 2020, par jjakeryan

  I'm trying to make a program that downloads videos from TikTok and combines all the separate videos into one .mp4 file and moves the final video to a folder on my desktop. I've been able to make it download all the videos and when I watch the separate videos they play fine however when I combine the videos some of the videos are messed up and look like this but the audio is fine.

  



  #slecting all .mp4 files
    video_files = glob.iglob("*.mp4")

    print(video_files)
    clips = []

    for clip in video_files:  # For each mp4 file name
        clips.append(VideoFileClip(clip))  # Store them as a VideoFileClip and add to the clips list

    today = date.today()

    final = concatenate_videoclips(clips)  # Concatenate the VideoFileClips
    final.write_videofile(f"{today}.mp4", codec="libx264")


#moving completed video to folder on desktop
    shutil.move(f'{today}.mp4', '/Users/jacobmarrandio/Desktop/done_videos/')


  



  thanks for any help