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• How to get perspective coordinates from file for image overlay with ffmpeg ?

  1er novembre 2016, par Victor.dMdB

  Is it possible to do something like this purely with ffmpeg ?

  Lets say we have a text file with the frame by frame coordinates for the 4 corners where the image should go. ffmpeg has a perspective filter, but how would one get ffmpeg to pull the frame coordinates from the text file ? I’m guessing with a pipe of sorts ?

• changing frame-rate for .mov

  5 juin 2013, par Ryan Saxe

  So I have a script in python that uses urllib to download a bunch of images and I then use ImageMagick to add labels to the images and then throw them into a MOV file.

  My issue is that the MOV file is going at 30 frames per second, and that is way too fast for me to be able to watch what is happening. I need something that is more like 5-10 frames per second.

  Is there a way to do this in ImageMagick, FFmpeg or any other easily accessible and cross platform package ?

  EDIT 1 : showing my ImageMagick

  convert -quality 100 *.png my_movie.mov

  I wasn't able to find it, but is there some line I add like -frameRate or something like that to allow me to choose the frame rate ? I can also use FFmpeg along with it so if anybody knows, that would be greay

• Extracting a clip from a video with low fps

  1er juin 2016, par superMind

  I want to extract a clip from a video( downloaded from [1]) (which has low frame rate) by specifying the start and end time. In order to do that, I use the following command :

  ffmpeg -i example.webm -ss 116.38 -to 126.38 clip.mpg

  however, I get the following error :

  ---

  ffmpeg version N-80026-g936751b Copyright (c) 2000-2016 the FFmpeg developers
  
  built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  
  configuration: --extra-libs=-ldl --prefix=/opt/ffmpeg --mandir=/usr/share/man --enable-avresample --disable-debug --enable-nonfree --enable-gpl --enable-version3 --enable-libopencore-amrnb --enable-libopencore-amrwb --disable-decoder=amrnb --disable-decoder=amrwb --enable-libpulse --enable-libfreetype --enable-gnutls --enable-libx264 --enable-libx265 --enable-libfdk-aac --enable-libvorbis --enable-libmp3lame --enable-libopus --enable-libvpx --enable-libspeex --enable-libass --enable-avisynth --enable-libsoxr --enable-libxvid --enable-libvidstab
  
  libavutil 55. 24.100 / 55. 24.100
  
  libavcodec 57. 42.100 / 57. 42.100
  
  libavformat 57. 36.100 / 57. 36.100
  
  libavdevice 57. 0.101 / 57. 0.101
  
  libavfilter 6. 45.100 / 6. 45.100
  
  libavresample 3. 0. 0 / 3. 0. 0
  
  libswscale 4. 1.100 / 4. 1.100
  
  libswresample 2. 0.101 / 2. 0.101
  
  libpostproc 54. 0.100 / 54. 0.100
  
  Input #0, matroska,webm, from 'example.webm':
  
  Metadata:
  
  encoder : Google
  
  Duration: 00:04:22.29, start: 0.000000, bitrate: 207 kb/s
  
  Stream #0:0: Video: vp8, yuv420p, 630x360, SAR 1:1 DAR 7:4, 6 fps, 6 tbr, 1k tbn (default)
  
  Stream #0:1: Audio: vorbis, 44100 Hz, stereo, fltp (default)
  
  [mpeg1video @ 0x252f200] MPEG1/2 does not support 5/1 fps
  
  Output #0, mpeg, to 'clip.mpg':
  
  Metadata:
  
  encoder : Google
  
  Stream #0:0: Unknown: none, SAR 1:1 DAR 0:0 (default)
  
  Metadata:
  
  encoder : Lavc57.42.100 mpeg1video
  
  Stream #0:1: Unknown: none (default)
  
  Metadata:
  
  encoder : Lavc57.42.100 mp2
  
  Stream mapping:
  
  Stream #0:0 -> #0:0 (vp8 (native) -> mpeg1video (native))
  
  Stream #0:1 -> #0:1 (vorbis (native) -> mp2 (native))
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
  
  -----------------------------------------------------

  I tried by adding -r 20 to the above command. It works in this case but not sure this is correct way to do it.
  I was wondering how can I extract the clip from this video given start time and endtime ? what are parameters should I use ? or what is correct way to do it ?

  Thanks.

  [1]https://www.youtube.com/watch?v=Yc52pGHr0xc