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• Encoding and decoding timestamps per frame using libav* into mp4

  9 mai 2019, par Kevin

  I am writing a program for recording and playing back video together with another program that is connected to a piece of hardware we sell. This other program gathers data from hardware, which contains "timestamp" counters at a fixed sampling rate.

  I am looking for a way to encode these timestamps (either raw or converted to unix) into the outputted mp4 file. The main reason being that the video stream might only start getting saved a few minutes into the hardware acquisition

  Recording :

                  timestamp
  
  Main program --------------->  Video program
  
    |                                 |
  
    |                                 |
  
    v                                 v
  
  Save hardware data               Save frame data
  
    and timestamp                    and timestamp
  
  
  
    |                                 |
  
    |                                 |
  
    v                                 v
  
  Custom data format                .mp4 file

  Post processing analysis :

  for i in range(0,datalen):
  
      hardwareData, timestamp = readHardwareFile()
  
      frame, timestamp = readMP4()
  
  
  
      myData[timestamp].hardware = hardwareData
  
      mydata[timestamp].video = frame
  
  
  
  analyze(myData)

  The goal being that when a I want to playback in VLC, or with OpenCV, I have access to timestamps for each frame.

  I currently save it as a separate text file with timestamp and frame #, but I’m wondering if there is a more standardized way to do this.

• riff : don’t overwrite bps from WAVEFORMATEX if EXTENSIBLE doesn’t contain that data.

  2 mai 2012, par Hendrik Leppkes

  riff : don’t overwrite bps from WAVEFORMATEX if EXTENSIBLE doesn’t contain that data.
  According to the specification on the MSDN [1], 0 is valid for that
  
  particular field, and it should be ignored in that case.
  [1] : http://msdn.microsoft.com/en-us/library/windows/desktop/dd757714(v=vs.85).aspx
  Bug-Id : 950
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DBH] libavformat/riffdec.c

• How to create a video in .net6 [closed]

  22 mai 2023, par mans

  I am trying to create a video from a series of images i .net core (6.0)

  


  I am looking for a solution like this :

  


  VideoCreator video=new VideoCreator("MyVideo.mp4");

for (int i=0;i<1000;i++)
{
     var image=getImage();
     video.addFrame(image);
}
video.close();


  


  I already tried these solutions, and I could not make them work or compile :

  


  OpenCVSharp

  


  This is compiling properly in .net 6 but is sot reliable when writing videos. I could get a blank video, especially if the getImage function took a long time to return an image (for example, 20 sec) and the above code is run in a thread. All in one : the system did not produce video reliably.

  


  AForge.net

  


  This library and its related library (Accord.NET) don't work on.net core. My attempt to use them did not produce any compilable software (for example AForge.video.ffmpeg or AForge.Video.VFW) are not available in .net core).

  


  So my questions :

  


  

  1. What is the best way to create a video in .net core reliably ?

  


  2. I am using .net core as I am using Microsoft ML engine, is the ML engine available for framework ?

  


  3. My target platform is Windows, is there any way that I can combine .net and framework applications/libraries ?