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• Use OpenH264 instead of libx264 in ffmpeg ?

  26 août 2020, par MING

  I use node-fluent-ffmpeg module to call ffmpeg.exe in my node.js app

  


  How to use OpenH264 when calling ffmpeg.exe ?

  


  Do I need to recompile ffmpeg ?

  


  But compiling ffmpeg looks complicated...

  


  The actual code is probably like this

  


  var FfmpegCommand = require('fluent-ffmpeg');
var FFMPEG_PATH = "C:/ffmpeg/bin/ffmpeg.exe" // binary file
FfmpegCommand.setFfmpegPath(FFMPEG_PATH)

FfmpegCommand("dog.webm", {})
    .videoCodec('libx264')
    // command line 
    // .addOutputOption([
    //     '-threads 8'
    // ])
    .on('start', function (commandLine) {
        // Actual ffmpeg command
        // ffmpeg -i C:\Users\ming\Pictures\WEBCAMCAPTURE\dog.webm -y -vcodec libx264 C:\Users\ming\Pictures\WEBCAMCAPTURE\dog_x264.mp4
        console.log('command' + commandLine)
    })
    .on('progress', function (progress) {
        console.log('Processing: ' + progress.percent + '% done')
    })
    .on('end', function () {
        console.log('Finished')
    })
    .save("dog_x264.mp4")



  


  English isn’t my first language, so please excuse any mistakes.

  


• How can I render frames decoded by FFmpeg using hardware decoding with D3D11 ?

  14 juin 2024, par mercuric taylor

  I have completed the process of decoding a video frame using FFmpeg. The format of the decoded frame is AV_PIX_FMT_NV12. Now, I want to render this frame to the screen using D3D11. My questions are :

  


  

  1. What is the equivalent concept in D3D11 for a decoded frame ? Is it a texture ?

  


  2. I have seen many solutions that convert NV12 data to RGB, but it seems that DX11 does not require this conversion anymore.

  


  3. I just want to display this frame, and since my frame is on the GPU, is there a more convenient way to render directly on the GPU without copying ?

  


  


  Please forgive my not-so-good English. Can anyone provide a reference example ?

  


  I have already referenced this open-source project. texthttps://github.com/balapradeepswork/D3D11NV12Rendering/tree/master/D3D11NV12Rendering
But I don't understand it very well.
Since I don't use dx11 to make game, just for show video, I am looking forward for a more easy solution. It has worried me for weeks, can anyone give me some advice(even good tutorial, some I can found is too old). Thanks sincerely !

  


• Accurate FFmpeg capture start time

  28 juillet 2016, par Adam

  I’m using ffmpeg from the command line to capture from a webcam to a file using the following :

  ffmpeg -y -rtbufsize 702000k -f dshow -s 320x240 -r 25 -i video="<device>" -t 10 -vcodec mjpeg -q:v 2 out.mp4
  
  </device>

  There is a slight delay between executing the command and the start of the capture ( 0.5 sec).
  I’m trying to find a way to accurately determine the start time (UTC/GMT) of the capture.

  My initial thought was to use the file-creation time as this might accurately reflect when the first frame was encoded (as opposed to when the command was executed). Unfortunately the file creation time is only accurate to the second which is not precise enough (and I’m not sure this would have given an accurate result anyway).

  My next thought was to use ffmpegs timestamp option. According to the documentation (http://www.ffmpeg.org/ffmpeg.html) :

  ‘-timestamp time (output)’

  Set the recording timestamp in the container. The syntax for time is:
  
  
  
  now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH:MM:SS[.m...])|(HHMMSS[.m...]))[Z|z])

  If the value is "now" it takes the current time. Time is local time unless ’Z’ or
  ’z’ is appended, in which case it is interpreted as UTC. If the year-month-day part
  is not specified it takes the current year-month-day.

  So I added the option :

  ffmpeg -y -rtbufsize 702000k -f dshow -s 320x240 -r 25 -i video="<device>" -t 10 -vcodec mjpeg -q:v 2 -timestamp now out.mp4
  
  </device>

  Unfortunately ffmpeg doesn’t seem to like this :

  Option timestamp (set the recording timestamp (’now’ to set the
  current time)) cannot be applied to output file out.mp4 — you are
  trying to apply an input option to an output file or vice versa. Move
  this option before the file it belongs to.

  Error parsing options for output file out.mp4.

  Error opening output files : Error number -22 occurred

  The documentation says -timestamp is an output option and it appears to be applied to the output file so I’m confused by this error.

  Can anyone suggest a way to accurately determine the capture start time ?

  Does anyone know why the -timestamp option gives an error ?