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• ffmpeg alpha merge mp4 to alpha mov (heic)

  25 mars 2022, par Alex

  I have two video files (mp4), matte/alpha (white silhouette) and normal.
I want to create a .mov file with transparent background that is possible to play on iOS/Safari devices.

  


  Commands I'm trying to run :

  


  ffmpeg -i color.mp4 -i alpha.mp4 -filter_complex '[1][0]scale2ref[mask][main];[main][mask]alphamerge' -c:v libx265 -tag:v hvc1 -pix_fmt yuva420p output.mov

ffmpeg -i color.mp4 -i alpha.mp4 -filter_complex '[1][0]scale2ref[mask][main];[main][mask]alphamerge' -c:v qtrle output.mov


  


  Expected result : Transparent background

  


  Actual result : Background is not transparent

  


  What I'm trying to achieve :
https://rotato.app/blog/transparent-videos-for-the-web

  


• Using ffmpeg to create a video from a sequence of TGA images, with a depth of field blur effect sourced from the TGA's alpha channel

  19 mars 2016, par vpvp

  I’m working on turning a sequence of TGA images into a video using ffmpeg. I want the video to have a depth of field blur effect. The alpha channel of each TGA contains a depth-mask, where black=close and white=far. I want to use this info to add DOF blur to the final output of that frame. After searching, the closest answer I could find was this
  http://superuser.com/questions/916431/ffmpeg-filter-to-boxblur-and-greyscale-a-video-using-alpha-mask, but it is for a static dof-mask. The DOF mask I would be using is obviously changing every frame, and an alpha channel instead of a seperate png.

  Here is my current cmd line

  ffmpeg -framerate 60 -i image.%10d.tga -c:v libx264 -preset slow -crf 0 -c:a copy -pix_fmt yuv420p output0.mp4

  It seems the answer would involve some use of alphamerge/alphaextract/boxblur, but I’m brand new to ffmpeg so I don’t know how to formulate the command.

  Thanks in advance.

• Real time livestreaming - RPI

  24 avril 2022, par Victor

  I work at a telehealth company and we are using connected medical devices in order to provide the doctor with real time information from these equipements, the equipements are used by a trained health Professional.

  


  Those devices work with video and audio. Right now, we are using them with peerjs (so peer to peer connection) but we are trying to move away from that and have a RPI with his only job to stream data (so streaming audio and video).

  


  Because the equipements are supposed to be used with instructions from a doctor we need the doctor to receive the data in real time.

  


  But we also need the trained health professional to see what he is doing (so we need a local feed from the equipement)

  


  How do we capture audio and video

  


  We are using ffmpeg with a go client that is in charge of managing the ffmpeg clients and stream them to a SRS server.
This works but we are having a 2-3 sec delay when streaming the data. (rtmp from ffmpeg and flv on the front end)

  


  ffmpeg settings :

  


  ("ffmpeg", "-f", "v4l2", `-i`, "*/video0", "-f", "flv", "-vcodec", "libx264", "-x264opts", "keyint=15", "-preset", "ultrafast", "-tune", "zerolatency", "-fflags", "nobuffer", "-b:a", "160k", "-threads", "0", "-g", "0", "rtmp://srs-url")


  


  My questions

  


  

  • Is there a way for this set up to achieve low latency (<1 sec) (for the nurse and for the doctor) ?

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  • Is the way I want to achieve this good ? Is there a batter way ?

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  Flow schema

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  Data exchange and use case flow

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