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• FFMPEG exported video is all black

  5 mars 2024, par Kartikey

  I am trying to generate a video wall of 4 videos using ffmpeg like the given image

  


  

  


  I am exceuting this below script to get the desired result

  


  def merge_videos(output_file):
    command = [
        'path_to_ffmpeg/ffmpeg.exe',
        '-i', 'path/playblasts/front.mp4',
        '-i', 'path/playblasts/side.mp4',
        '-i', 'path/playblasts/persp1.mp4',
        '-i', 'path/playblasts/persp2.mp4',
        '-filter_complex', '[0:v][1:v][2:v][3:v]xstack=inputs=4:layout=0_0|w0_0|0_h0|w0_h0[v]',
        '-map', '[v]',
        output_file
    ]
    subprocess.run(command)


  


  where as passing output file path as argument, but I am getting below result

  


  

  


  Any help would be appreciated.
Thanks & Best Regards

  


• Custom h.264 streams broken in some hardware decoders

  20 septembre 2021, par Charles Lohr

  I've been banging my head against a wall on this one. I'm working on a mechanism to code data into a valid h.264 stream. I've gotten it working and it plays back with tools like mplayer, celluloid, and vlc (software, VA-API and VA-API with DRM), and ffmpeg. ffmpeg can even repackage and all is well.

  


  But, in situations where hardware decoding is used for instance VDPAU, it doesn't work at all.

  


  This also holds true on windows !

  


  This can be seen on this example code here : https://www.cardinalpeak.com/blog/worlds-smallest-h-264-encoder

  


  The code I'm working with is a little more sophisticated and only has timestamp warnings in ffmpeg, https://github.com/cnlohr/h264fun/blob/dfa95a6ed0b669fe1e15d67cd3cbd45ac24cc79d/testbase.c

  


  But some of the things I'm worried about is if I_PCM is supported in hardware decoding or what could possibly be triggering issues ?

  


• FFMPEG : Cannot record audio when using android_camera on Android mobile device or emulator

  12 octobre 2023, par JackE99

  I am attempting to livestream video and audio to my local network from a mobile android device as a use case for the company i work for.

  


  After searching around, I was able to create a video stream using the following command :

  


  ffmpeg -f android_camera -i 0 -c:v libx264 -f flv rtmp://$url

  


  The only issue with this command is in the title, I cannot figure out how to get audio input from the microphone built into the device. I have tried different iterations such as :

  


  Using android_audio

  


  ffmpeg -f android_camera -i 0 -f android_audio -i 0 -c:v libx264 -c:a aac -f flv rtmp://$url

  


  Using mapping

  


  ffmpeg -f android_camera -i 0 -f android_audio -i 0 -map 0:v -map 1:v -c:v libx264 -c:a aac -f flv rtmp://$url

  


  I feel as though I have hit a wall and am unable to progress. And before it is said, yes I do need to use FFMPEG as the command medium and cannot use a prebuilt project/package as the devices have a program already installed to take FFMPEG commands. Any help on this topic is greatly appreciated.

  


  P.S. If you can also help me figure out how to find the name of an Android device's internal microphone, that would be lovely.