Recherche avancée

Sur d’autres sites (6751)

• From 2 videos create one split screen video, 2 separate audio streams and a thumbnail from the resultant split screen video - all in one pass

  27 avril 2020, par Ben Hardy

  I'm using ffmpeg to create several single splitscreen videos out of 2 separate videos. The 2 videos have audio so I want to extract the 2 video's audio streams as 2 separate mp3s and also create a thumbnail out of the finished splitscreen video. Is it possible to do these 3 actions in one pass ?
  
Here is the code I'm using to create the splitscreen and the 2 separate mp3

  



  ffmpeg -i input0.mov -i input1.mov -filter_complex "[0]scale=640x360[v0];[1]scale=640x360[v1];[v0][v1] hstack[v]" -map "[v]" output.mp4 -map 0:a audio0.mp3 -map 1:a audio1.mp3

  



  However I want to also create a thumbnail out of the resultant split screen video in the same pass, but if I add "image.jpg" at the end it only makes a thumbnail out of input1.mov not the resultant splitscreen video made from input0 and input1 and makes all the outputs only 1 frame long. Here is the code :

  



  ffmpeg -i input0.mov -i input1.mov -filter_complex "[0]scale=640x360[v0];[1]scale=640x360[v1];[v0][v1] hstack[v]" -map "[v]" output.mp4 -map 0:a audio0.mp3 -map 1:a audio1.mp3 image.jpg

  



  Is there a solution to this that will let me create all the correct outputs in one pass ?

  


• FFMPEG How to overwrite existing file without making a copy ?

  13 août 2022, par Dresden21

  I am using this command to add a watermark to all videos in a file :
for %i in ("*.mp4") do ffmpeg -i "%i" -i wm.png -filter_complex "overlay=main_w/2-overlay_w/2" -codec:a copy "file% ni.mp4"

  


  It makes a copy of each video when it's done. How can I make it overwrite the current videos so I don't get a bunch of copies ? I'd like each file to be overwritten with the new changes.

  


• OpenCV+ffmpeg : Set max_analyze_duration ?

  3 avril 2013, par Christian Jonassen

  import sys
  
  import cv
  
  
  
  video = "http://192.168.1.15:8000/video.mjpg" # from motion
  
  capture = cv.CaptureFromFile(video)
  
  print capture
  
  cv.NamedWindow('Stream', 1 )
  
  
  
  while True:
  
    frame = cv.QueryFrame(capture)
  
  
  
    if frame is None:
  
      print "No frame, exiting program"
  
      break
  
    else:
  
      cv.ShowImage('Stream', frame)
  
      cv.WaitKey(20)

  , which sort of works. Meaning that after a while, I get

  Using network protocols without global network initialization. Please use avformat_network_init(), this will become mandatory later.
  
  Using network protocols without global network initialization. Please use avformat_network_init(), this will become mandatory later.
  
  [mjpeg @ 0xb46720] max_analyze_duration reached
  
  [mjpeg @ 0xb46720] Estimating duration from bitrate, this may be inaccurate
  
  Using network protocols without global network initialization. Please use avformat_network_init(), this will become mandatory later.
  
  Using network protocols without global network initialization. Please use avformat_network_init(), this will become mandatory later.
  
  [mjpeg @ 0xb46720] max_analyze_duration reached
  
  [mjpeg @ 0xb46720] Estimating duration from bitrate, this may be inaccurate
  
  <capture 0x7f0aed25c630="0x7f0aed25c630">
  
  </capture>

  The stream then works fine (it's a bit speedy in the start).

  It makes sense : FFMPEG finds the stream mysterious, and therefore analyzes it for the maximum duration, which makes the buffer full, and hence the speediness at the start. Now, is there a way I can (without recompiling FFMPEG) set max_analyze_duration, or otherwise pass some hints to FFMPEG so that it doesn't analyse the stream until max_analyze_duration has passed ?

  The stream is from the motion program : an MJPEG stream of 10 FPS with 640x480.