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• how to create Codec specific Data ( csd ) for h264 in MediaCodec ?

  24 février 2020, par Ahmed

  Hi i have android project that i have to receive audio and video from server via socket, the audio part run perfect.
  but the video part is not working i do not know what the reason because the decoder did not show any error when decoding video packets .
  the video codec that i use is H.264/AVC from ffmepeg encoder with the following settings :-

  tune = zerolatency

  profile = baseline

  level = 3

  Width = 320

  Height = 240

  frameRate = 30

  GOPSize = 30

  i found that i have to add CSD-0 and CSD-1 to MediaCodec config but i do not know how to add H.264 SPS/PPS data to the configurations

  this is code i was found , but it’s not wokring with me ,

  byte[] header_sps = { 0, 0, 0, 1, 103, 100, 0, 40, -84, 52, -59, 1, -32, 17, 31, 120, 11, 80, 16, 16, 31, 0, 0, 3, 3, -23, 0, 0, -22, 96, -108 };
  
  byte[] header_pps = { 0, 0, 0, 1, 104, -18, 60, -128 };
  
  
  
  MediaFormat videoFormat = MediaFormat.createVideoFormat(MediaFormat.MIMETYPE_VIDEO_AVC , 320 , 240 );
  
  videoFormat.setInteger(MediaFormat.KEY_MAX_INPUT_SIZE  , 100000);
  
  videoFormat.setByteBuffer("csd-0", ByteBuffer.wrap(header_sps));
  
  videoFormat.setByteBuffer("csd-1", ByteBuffer.wrap(header_pps));
  
  
  
  MediaCodec videoDecoder = MediaCodec.createDecoderByType(MediaFormat.MIMETYPE_VIDEO_AVC);
  
  videoDecoder.configure(videoFormat , surface , null , 0);
  
  videoDecoder.start();

  if some one know what the correct way to decode H.264 in this case this will be helpfull

• How to know the delay of frames between 2 videos, to sync an audio from video 1 to video 2 ?

  8 janvier 2021, par jaimepm

  world.

  


  I have many videos that I want to compare one-to-one to check if they are the same, and get from there the delay of frames, let's say. What I do now is opening both video files with virtualdub and checking manually at the beginning of video 1 that a given frame is at position, i.e., 4325. Then I check video 2 to see the position of the same frame, i.e., 5500. That would make a delay of +1175 frames. Then I check at the end of the video 1 another given frame, position let's say 183038. I check too the video 2 (imagine the position is 184213) and I calculate the difference, again +1175 : eureka, same video !
The frame I chose to compare aren't exactly random, it must be one that I know it is exactly one I can compare to (for example, a scene change, an explosion that appears from one frame to another, a dark frame after a lighten one...) and I always try to check for the first comparison frames within the first 10000 positions and for the second check I take at the end.
What I do next is to convert the audio from video 1 to video 2 calculating the number of ms needed, but I don't need help with that. I'd love to automatize the comparison so I just have to select video 1 and video 2, nothing else, that way I could forget forever virtualdub and save a lot of time.

  


  I'm tagging this post as powershell too because I'm making a script where at the moment I have to introduce the delay between frames (after comparing manually) myself. It would be perfect that I could add this at the beginning of the script.

  


  Thanks !

  


• ffmpeg from chrome native messaging host app not working

  9 juin 2014, par Moisés Olmedo

  OK, this is what I got, I’m using native messaging to fire a c++ program from a chrome extension in Windows.
  This c++ program (ehost.exe) creates a ffmpeg process for recording the input audio and saving it to mp3.
  I do this with the CreateProcess() function
  This works perfect when I open ehost.exe myself (double clicking it)
  but when I open it from my chrome extension (chrome.runtime.connectNative() ), the ffmpeg process opens but ffmpeg writes no output file, as if it didn’t have permissions...

  Anybody knows why ?
  This is the ehost.exe code for starting ffmpeg.exe

  static HANDLE startFFmpeg()
   {
       char cmd[] = "C:\Users\moizilla\Desktop\native\ffmpeg\bin\ffmpeg.exe -y -f dshow -i audio=\"Microphone (High Definition Aud\" -acodec libmp3lame C:\Users\moizilla\Desktop\native\kasdkddfodkadd.mp3";
       PROCESS_INFORMATION pi = {0};
       STARTUPINFO si={0};
       si.cb = sizeof(STARTUPINFO);
       if(CreateProcess(NULL, cmd, NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi)){
           CloseHandle(pi.hThread);
           return pi.hProcess;
       }
       return NULL;
}