Recherche avancée

Sur d’autres sites (10243)

• avfilter/af_surround : allow non-power of 2 win_size

  16 novembre 2022, par Paul B Mahol

  avfilter/af_surround : allow non-power of 2 win_size
  

  • [DH] libavfilter/af_surround.c

• Given 2 input videos of different lengths at 60 FPS with multiple common sections in between, what is the best way to sync them at the common section ?

  27 janvier 2024, par PirateApp

  
input vs output

  


  

  • In my actual case, there are 4 videos (basically gaming videos recorded from 4 different machines)

  


  • Each video may start or end at different duration (manually controlled by people starting and stopping recording and therefore their lengths vary slightly)

  


  • Each video has one or more common sections (basically a cutscene playing at the same time)

  


  • The distance between the common sections is the same in every video

  


  • How do I sync the videos at the common section ?

  


  • Basically I want to create a split screen video such that the common part plays at the same time on all the sub parts of the video

  


  • Keep in mind that the common sections wont be EXACTLY equal (because of graphics differences between machines but highly similar like dx9 vs dx11 or gamma)
What have I tried ?

  


  • Naive approach

  


  • Start video 1 at 0, start video 2 at 0.017, render the whole thing and check if it is in sync

  


  • Start video 1 at 0, start video 2 at 0.033, render the whole thing and check if it is in sync

  


  • Basically loop through the length of the video at each frame interval, render the full video and check if we get a synced version

  


  


  This sounds like a terrible idea honestly

  


    for (t1 in length of video a) {
    for (t2 in length of video b) {
       render a video with a and b starting at t1, t2 respectively
       increment t2 by 0.017 for b
    }
    increment t1 by 0.017 for a
  }


  


  Final output with 4 videos should look like this all synced at common sections


  


  Any better ideas ?

  


• Streaming a video to /dev/video0 using gstreamer and v4l2 shows a black screen [on hold]

  24 septembre 2019, par Lawliet

  I’ve been trying to use a video as a webcam for quite a while now. The command

  gst-launch-1.0 filesrc location=newflag.webm ! decodebin ! videoconvert ! v4l2sink device=/dev/video0

  Using this command, i’m able to watch the stream using VLC but Discord and Firefox display a black screen when using /dev/video0 as a webcam.

  I got it working using ffmpeg to stream the video in yuv420p so I suspect videoconvert converts the stream to YUY2 which is I guess not supported by Discord nor Firefox.

  Any idea on how to get this to work ?