Newest 'ffmpeg' Questions - Stack Overflow

Les articles publiés sur le site

• ffmpeg and extracting multiple frames

  4 décembre 2012, par Chud37

  I am using FFMPEG. I have to use it via shell_exec("ffmpeg...");. Currently I am extracting frames this way:

  shell_exec("ffmpeg -i /vid.mp4 -deinterlace -an -ss 20 -f mjpeg -t 1 -r 1 -y -s 141x76 ".ROOT."/thumbs/$newFileName.jpg 2>&1");

  I would like 5 frames from the video. I am doing this in a loop too, so each video duration will be different. And sometimes FFMPEG cannot get the duration of the video. Even so, I would like to be able to extract 5 different frames, at even points throughout the video, i.e. every 20%.

• Superimpose videos with FFmpeg [migrated]

  4 décembre 2012, par Jerre Baumeister

  We’re trying to edit a video with FFmpeg. One of our videos has an alpha channel and we want to superimpose this above another video.

  example:

  Video 01: Start frame 1     end frame 200
  Video 02: Start frame 100   end frame 300 
  

  A common function within video editing software is working with multiple layers. So far we haven't been able to find such a function within FFmpeg.

  Does anyone know how to do this? Any suggestion is welcome! (or if you know any other way to do this trough a unix command line we'd be glad to know)

• Encode video with changing bit rates using FFmpeg [migrated]

  4 décembre 2012, par Pavan K

  I would like to encode a 30 min video using ffmpeg. I am able to achieve this using

  ffmpeg -i in.mp4 -vcodec libvpx -vb 1024k -keyint_min 150 -g 150 -an out.webm
  

  But I would like to encode different segments of the video at different rate and not use a constant rate of 1024k. Is this possible?

  I know what time they have to switch encoding. For example say 5 min of video I want an encoding rate of 1024k and next 5 min I am okay with 250k bitrate. I do not want to use VBR or I don't want to cut the video and encode them at different rates and then join them.

  Is this possible. I read the man page for ffmpeg and saw there were options for

  startime and time 
  

  But I am not sure how exactly I can do this assuming this to be possible.

• Batch process ffmpeg ? [migrated]

  4 décembre 2012, par A T

  Given an AVI encapsulated video with WMA2 audio and MP4 video how do I pass-through the video, convert the audio to MP3; then re-encapsulate the entire file into an AVI?

  ffmpeg -i "foo bar.avi" -acodec libmp3lame "Converted\foo bar.avi"
  

  Now how do I do that same command for every .avi file in this directory?

  (need a solution using bash or Windows CLI [for?])

• Video Streaming from an ip camera h264

  4 décembre 2012, par user1764164

  I wish to develop an application for android which can receive video frames and display them in h264 encoded format. I was able to find solutions using mjpeg but i wish to use javacv which contains ffmpeg . Javacv also allows me to add motion detection and color enhancement algorithms to my frames. Please point me to references and solutions which would enable me to further the development of my application