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• Create video with size based on image and place a video somewhere with an offset

  10 mars 2024, par NoKey

  I am trying out FFMPEG and I am unsure how hard it is to do what I want. I have some device frames and I want to play a video inside the frame. For example, this is a device frame :

  


  

  


  Now I want to play a video within the screen of the iPhone. I already got the exact X and Y offset where the video must be placed to show it correctly. I have the following challenges to make it work, and I want to make sure FFMPEG can do it before I spend to much time reinventing the wheel :

  


  


  • The output of the video must be as big as the PNG. This is already a
confusing part for me. I have the width and height already available,
but the things I saw is that FFMPEG will take over the input of the
video as final size. The final output of the video should of course
be the length of the input video.

    


  


  • The background must be transparant (so no black background, I want to
play the video on top of a website so it's nice if it's transparant and the corners are not black).

    


  


  • The ability to place a video somewhere with a specified X and Y
offset inside the device frame.

    


  


  • Not sure if it's possible in the same command, but maybe the video
needs to be resized to make it fit. I got the exact dimensions for
the video.

    


  


  


  The things I struggle most is point 1 where the output video must have a transparant background and where the device frame is placed in. Does anybody got tips ?

  


• iOS switching between audio & subtitle tracks added using ffmpeg

  27 décembre 2019, par Tony M

  Edit : Title altered to reflect that the answer and comments by @llogan cover switching between both audio and subtitle tracks.

  I have an m.mp4 with English audio and want to add a second audio stream in Italian so that I can play either language using the iPhone. When I used this command :

  ffmpeg -i m.mp4 -i ita.mp3 -c copy -map 0 -map 1 out.mp4 

  the output from ffmpeg -i out.mp4 (see below) shows that a new audio stream is added, and I can switch between audio streams using the VLC player. Yet when I transfer the video to the TV app and play it on either MacOS or iOS it only plays the original English and I see no options to play other languages.

  How do I get it to be able to switch between either audio on iOS ?

  Here is the output from ffmpeg -i out.mp4:

      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 400x300 [SAR 1:1 DAR 4:3], q=2-31, 482 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 24k tbc (default)
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 102 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
      Stream #0:2: Audio: mp3 (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 152 kb/s
  
      Metadata:
  
        encoder         : LAME3.100
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
    Stream #0:1 -> #0:1 (copy)
  
    Stream #1:0 -> #0:2 (copy)

• ffmpeg won't execute properly in google app engine standard nodejs

  3 septembre 2019, par tommyc38

  I have tried for three full days to get GAE (standard - nodejs) to run a simple video transcoder from MOV to MP4 using ffmpeg. I have tried using ffluent-ffmpeg, kicking off a child process (e.g. spawn), and nothing works. As soon as it hits the call to the executable it always errors. I have confirmed ffmpeg is installed and even tried using ffmpeg-static. Moreover, I have it working on my local machine with no problems (using all of the aforementioned ways).

  I have also tried logging the errors and nothing is really all that helpful. I can see its working through any installed package including ffmpeg (system package).

  Below is the pseudo code...step three is where the problem occurs.

  1. Send file name to GAE endpoint
  2. Download the file from google cloud storage to a temp file
  3. Transcode using ffmpeg
  4. Upload temp file to google cloud storage
  5. Remove old google cloud storage file
  6. Remove temp file

  The file I am using to test is 6MB...a 5 second video I took on my iPhone. Thank you in advance.

  UPDATE : I successfully deployed the exact same code to Node Flex environment and everything works great. I wasn’t able to get any errors in the standard environment that directed me where to look but my guess is it has something to do with how it stores the file I pipe into FFMPEG on GAE Node Standard. The docs say its a virtual file system that uses RAM. I’d love to hear if anybody managed to get it working in the standard environment.