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• input stream error _read() is not implemented : ffmpeg-fluent

  23 mai 2018, par Thomsheer Ahamed

  I have buffer object. I want to pass that buffer as readable stream to ffpmeg.

  var ffmpeg = require('fluent-ffmpeg');
  
      var ffmpegPath = require("ffmpeg-binaries").ffmpegPath()
  
      ffmpeg.setFfmpegPath(ffmpegPath);
  
      var command = new ffmpeg();
  
  
  
      command.input(my_buffer)
  
          .videoCodec('libx264')
  
          .size('520x?')
  
          .aspect('4:3')
  
          .inputFPS(8)
  
          .outputFPS(30)
  
          .output('new_video.mp4')
  
          .on('start', onStrat)
  
          .on('progress', onProgress)
  
          .on('end', onEnd)
  
          .on('error', onError)
  
          .run();

  If I pass buffer right away I will get "Error : Invalid input
  at FfmpegCommand.proto.mergeAdd.proto.addInput.proto.input"

  So I converted buffer into stream using

  function bufferToStream(buffer) {
  
      let Duplex = require('stream').Duplex;
  
      let stream = new Duplex();
  
      stream.push(new Buffer(buffer));
  
      stream.push(null);
  
      return stream;
  
  }
  
  var red = bufferToStream(finalResponse.file.buffer);

  and passed this steam to input

  command.input(red)

  Above Command throws "ffmpeg exited with code 1 : Error opening filters !" ;

  If I use my_buffer and save it in locally using fs.writeFile(’path’,my_buffer) and pass this path to input of ffmpeg then it works fine..

  But I dont want to store that file and then delete it after altering video.

  Can some one help me ?

  I Reffered this example

• No frame decodes after upgrading from ffmpeg 1.1 to 3.3

  13 juin 2018, par M.Mahdipour

  I have a source code in C++ using libavcodec for decoding h264 rtsp stream frames. This source code was written using ffmpeg 1.1. Now when I upgraded to ffmpeg 3.3, all things seem to work correctly except that decoding frames not work.
  In old version, I was using avcodec_decode_video2. After upgrading, avcodec_decode_video2 always sets got_picture to 0 and return value is equal to the size of the input packet (which means all data is used). And never a frame is decoded.
  I have also removed avcodec_decode_video2 and done decoding with avcodec_send_packet and avcodec_receive_frame, but avcodec_send_packet always returns 0 and avcodec_receive_frame always returns -11 (EAGAIN).

  This is the code I use for decoding :

  #include "stdafx.h"
  
  #include 
  
  #include <string>
  
  #include <iostream>
  
  using namespace std;
  
  
  
  extern "C"{
  
  #include "libavformat/avformat.h"
  
  #include "libavcodec/avcodec.h"
  
  #include "libswscale/swscale.h"
  
  #include "libavutil/pixfmt.h"
  
  }
  
  
  
  int extraDataSize;
  
  static const int MaxExtraDataSize = 1024;
  
  uint8_t extraDataBuffer[MaxExtraDataSize];
  
  
  
  void AddExtraData(uint8_t* data, int size)
  
  {
  
      auto newSize = extraDataSize + size;
  
      if (newSize > MaxExtraDataSize){
  
          throw "extradata exceeds size limit";
  
      }
  
      memcpy(extraDataBuffer + extraDataSize, data, size);
  
      extraDataSize = newSize;
  
  }
  
  
  
  int _tmain(int argc, _TCHAR* argv[])
  
  {
  
      std::string strFramesPath("g:\\frames\\");
  
  
  
      AVCodec* avCodec;
  
      AVCodecContext* avCodecContext;
  
      AVFrame* avFrame;
  
      AVCodecID codecId = AV_CODEC_ID_H264;
  
      unsigned char sprops_part_1[9] = { 0x27, 0x42, 0x80, 0x1f, 0xda, 0x02, 0xd0, 0x49, 0x10 };
  
      unsigned char sprops_part_2[4] = { 0x28, 0xce, 0x3c, 0x80 };
  
  
  
      av_register_all();
  
      avcodec_register_all();
  
      avCodec = avcodec_find_decoder(codecId);
  
      avCodecContext = avcodec_alloc_context3(avCodec);
  
      if (!avCodecContext)
  
      {
  
          cout &lt;&lt; "avcodec_alloc_context3 failed." &lt;&lt; endl;
  
          return 0;
  
      }
  
      uint8_t startCode[] = { 0x00, 0x00, 0x01 };
  
  
  
      // sprops
  
      {
  
          // sprops 1
  
          AddExtraData(startCode, sizeof(startCode));
  
          AddExtraData(sprops_part_1, 9);
  
          // sprops 2
  
          AddExtraData(startCode, sizeof(startCode));
  
          AddExtraData(sprops_part_2, 4);
  
  
  
          avCodecContext->extradata = extraDataBuffer;
  
          avCodecContext->extradata_size = extraDataSize;
  
      }
  
  
  
      AddExtraData(startCode, sizeof(startCode));
  
      avCodecContext->flags = 0;
  
      if (avcodec_open2(avCodecContext, avCodec, NULL) &lt; 0)
  
      {
  
          cout &lt;&lt; "failed to open codec" &lt;&lt; endl;
  
          return 0;
  
      }
  
      avFrame = av_frame_alloc();
  
      if (!avFrame)
  
      {
  
          cout &lt;&lt; "failed to alloc frame" &lt;&lt; endl;
  
          return 0;
  
      }
  
  
  
      void *buffer = malloc(100 * 1024);  // 100 KB buffer - all frames fit in this buffer
  
      for (int nFrameIndex = 0; nFrameIndex &lt; 257; nFrameIndex++)
  
      {
  
          std::string strFilename = std::string("g:\\frames\\" + std::to_string(nFrameIndex));
  
          FILE* f = fopen(strFilename.c_str(), "rb");
  
          fseek(f, 0, SEEK_END);
  
          long nFileSize = ftell(f);
  
          fseek(f, 0, SEEK_SET);
  
          size_t nReadSize = fread(buffer, 1, nFileSize, f);
  
          // cout &lt;&lt; strFilename &lt;&lt; endl;
  
          if (nReadSize != nFileSize)
  
          {
  
              cout &lt;&lt; "Error reading file data" &lt;&lt; endl;
  
              continue;
  
          }
  
          AVPacket avpkt;
  
          avpkt.data = (uint8_t*)buffer;
  
          avpkt.size = nReadSize;
  
  
  
          while (avpkt.size > 0)
  
          {
  
              int got_frame = 0;
  
              auto len = avcodec_decode_video2(avCodecContext, avFrame, &amp;got_frame, &amp;avpkt);
  
              if (len &lt; 0) {
  
                  //TODO: log error
  
                  cout &lt;&lt; "Error decoding - error code: " &lt;&lt; len &lt;&lt; endl;
  
                  break;
  
              }
  
              if (got_frame)
  
              {
  
                  cout &lt;&lt; "* Got 1 Decoded Frame" &lt;&lt; endl;
  
              }
  
              avpkt.size -= len;
  
              avpkt.data += len;
  
          }
  
      }
  
  
  
      getchar();
  
      return 0;
  
  }
  
  </iostream></string>

  Test frames data can be downloaded from this link :
  Frames.zip ( 3.7MB)

  I have used windows builds from Builds - Zeranoe FFmpeg
  If you copy paste this code into your IDE, the code compiles successfully. Using libavcodec new versions, no frame is decoded. Using old version of libavcodec (20141216-git-92a596f), decoding starts when feed frame 2.

  Any ideas ?

• How to fetch both live video frame and timestamp from ffmpeg to python on Windows

  8 mai 2018, par vijiboy

  Searching for an alternative as OpenCV would not provide timestamps for live camera stream (on Windows), which are required in my computer vision algorithm, I found ffmpeg and this excellent article https://zulko.github.io/blog/2013/09/27/read-and-write-video-frames-in-python-using-ffmpeg/
  The solution uses ffmpeg, accessing its standard output (stdout) stream. I extended it to read the standard error (stderr) stream as well.

  Working up the python code on windows, while I received the video frames from ffmpeg stdout, but the stderr freezes after delivering the showinfo videofilter details (timestamp) for first frame.

  I recollected seeing on ffmpeg forum somewhere that the video filters like showinfo are bypassed when redirected. Is this why the following code does not work as expected ?

  Expected : It should write video frames to disk as well as print timestamp details.
  Actual : It writes video files but does not get the timestamp (showinfo) details.

  Here’s the code I tried :

  import subprocess as sp
  
  import numpy
  
  import cv2
  
  
  
  command = [ 'ffmpeg', 
  
              '-i', 'e:\sample.wmv',
  
              '-pix_fmt', 'rgb24',
  
              '-vcodec', 'rawvideo',
  
              '-vf', 'showinfo', # video filter - showinfo will provide frame timestamps
  
              '-an','-sn', #-an, -sn disables audio and sub-title processing respectively
  
              '-f', 'image2pipe', '-'] # we need to output to a pipe
  
  
  
  pipe = sp.Popen(command, stdout = sp.PIPE, stderr = sp.PIPE) # TODO someone on ffmpeg forum said video filters (e.g. showinfo) are bypassed when stdout is redirected to pipes??? 
  
  
  
  for i in range(10):
  
      raw_image = pipe.stdout.read(1280*720*3)
  
      img_info = pipe.stderr.read(244) # 244 characters is the current output of showinfo video filter
  
      print "showinfo output", img_info
  
      image1 =  numpy.fromstring(raw_image, dtype='uint8')
  
      image2 = image1.reshape((720,1280,3))  
  
  
  
      # write video frame to file just to verify
  
      videoFrameName = 'Video_Frame{0}.png'.format(i)
  
      cv2.imwrite(videoFrameName,image2)
  
  
  
      # throw away the data in the pipe's buffer.
  
      pipe.stdout.flush()
  
      pipe.stderr.flush()

  So how to still get the frame timestamps from ffmpeg into python code so that it can be used in my computer vision algorithm...