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• Encoding MJPEG from webcam in UWP development with C#

  24 avril 2018, par Federico Parra

  this is my first question in StackOverflow.

  How can I encode video being captured from webcam as a MJPEG using C# in UWP enviroment (Visual Studio 2017) ?
  Perhaps using FFMPEG or DirectShow ? Any particular bindings required to use them in UWP ?

  I’ve been through these walk-throughs trying to go the official way using MediaCapture :

  https://docs.microsoft.com/en-us/windows/uwp/audio-video-camera/basic-photo-video-and-audio-capture-with-mediacapture
  https://docs.microsoft.com/en-us/uwp/api/windows.media.capture.mediacapture

  According to Microsoft though, there is no MJPEG encoder included in MediaEncoder (only decoder) : https://docs.microsoft.com/en-us/windows/uwp/audio-video-camera/supported-codecs

  About FFMPEG UWP integration, I found this :
  https://github.com/Microsoft/FFmpegInterop
  https://blogs.windows.com/buildingapps/2015/06/05/using-ffmpeg-in-windows-applications/#HHYbWAVcM7LhkvYZ.97

  But it’s geared towards decoding, and I want to encode.

  Just in case someone is wondering, I want to use MJPEG for Two reasons :
  1) less CPU intensive (much less) because it doesn’t do inter-frame compression, means my Surface Pro (and other similar computers) will keep quiet without fans running like crazy
  2) I need all frames (i.e. not one every 30) to be crystal clear because of an algorithm I need to run on each of them after

  Any pointers would be greatly appreciated.

  Thank you,
  Federico

• avcodec/exr : preserve half-float NaN bits and add fate test

  23 novembre 2020, par Mark Reid

  avcodec/exr : preserve half-float NaN bits and add fate test
  Handles NaNs more like the official implementation handles them, preserving
  
  the original bits.
  

  • [DH] libavcodec/exr.c
  • [DH] tests/fate/image.mak
  • [DH] tests/ref/fate/exr-rgb-scanline-zip-half-0x0-0xFFFF

• How to use ffmpeg to push my Unity3d process screenshot to nginx-rtmp server ?

  26 mars 2019, par Menghui

  I want to broadcast my Unity process screen.

  What I can think of is to use the Unity screenshot, then pipe png to the ffmpeg process, ffmpeg encodes png into h264 and pushes it to the server.

  How to use ffmpeg and named pipe to encod and push stream ?

  1. About png to h264, is this possible to push ? (But I can’t play server video stream with vlc)

  .\ffmpeg.exe -framerate 24 -i .\screenshot%03d.png -vcodec libx264 -acodec aac -strict -2 -f h264 rtmp://xxx.xxx.xxx.xxx/live

  png -> rtmp image

  2. About ffmpeg and named pipes, it seems to be written, and can not be read.

  # write
  
  .\ffmpeg.exe -i test.mp4 -f h264 pipe:MyPipe

  mp4 -> pipe image

  # read and push stream
  
  .\ffmpeg.exe -re -i pipe:MyPipe -vcodec libx264 -acodec aac -strict -2 -f h264 rtmp://xxx.xxx.xxx.xxx/live

  pipe -> rtmp image

  And ffmpeg official website does not seem to have an introduction about named pipes.

  Thank you for your help !