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• lavf/mov.c : Parse upto 2 keyframes after the edit list end in mov_fix_index.

  10 novembre 2017, par Sasi Inguva

  lavf/mov.c : Parse upto 2 keyframes after the edit list end in mov_fix_index.
  Partially fixes t/6699.
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/mov.c
  • [DH] tests/fate/mov.mak
  • [DH] tests/ref/fate/mov-elst-ends-betn-b-and-i

• How to edit a frame's content using ffmpeg and opencv ?

  15 août 2017, par md612

  I am going to edit the content of one frame from a mp4 file using OpenCV and ffmpeg 3.3. However, I encountered some problems such as the width and the height of video are zero, some functions are deprecated. I have changed the old function to updated function, but still cannot extract a correct frame. Please help.

  Can anyone show an example of extracting a frame from a mp4 file using ffmpeg 3.3 ?

  #include "stdafx.h"
  
  #include <iostream>
  
  #include <vector>
  
  #include <opencv2></opencv2>core/core.hpp>
  
  #include <opencv2></opencv2>highgui/highgui.hpp>
  
  #include <opencv2></opencv2>imgproc/imgproc.hpp>
  
  // FFmpeg
  
  extern "C" {
  
  #include <libavformat></libavformat>avformat.h>
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #include <libavutil></libavutil>avutil.h>
  
  #include <libavutil></libavutil>pixdesc.h>
  
  #include <libswscale></libswscale>swscale.h>
  
  #include <libavutil></libavutil>imgutils.h>
  
  
  
  }
  
  #define CODEC_TYPE_VIDEO      AVMEDIA_TYPE_VIDEO
  
  
  
  int main(int argc, char* argv[])
  
  {   
  
      // initialize FFmpeg library
  
      av_register_all();
  
      //  av_log_set_level(AV_LOG_DEBUG);
  
      int ret;
  
  
  
      // open input file context
  
      AVFormatContext* inctx = nullptr;
  
      //ret = avformat_open_input(&amp;inctx, infile, nullptr, nullptr);
  
      ret = avformat_open_input(&amp;inctx, "C:\\car.mp4", nullptr, nullptr);
  
      // retrive input stream information
  
  
  
  
  
      ret = avformat_find_stream_info(inctx, nullptr);
  
      if (ret &lt; 0) {
  
      std::cerr &lt;&lt; "fail to avformat_find_stream_info: ret=" &lt;&lt; ret;
  
      return 2;
  
      }
  
  
  
      // find primary video stream
  
  
  
  
  
      AVCodec* vcodec = nullptr;
  
      vcodec = avcodec_find_decoder(AV_CODEC_ID_MPEG4);
  
      if (!vcodec) {
  
          fprintf(stderr, "Codec not found\n");
  
          exit(1);
  
      }
  
  
  
      const int vstrm_idx = ret;
  
      AVStream* vstrm = inctx->streams[vstrm_idx];
  
  
  
      // open video decoder context
  
      AVCodecContext *c = NULL;
  
      c = avcodec_alloc_context3(vcodec);
  
      if (!c) {
  
          fprintf(stderr, "Could not allocate video codec context\n");
  
          exit(1);
  
      }
  
  
  
      if (avcodec_open2(c, vcodec, NULL) &lt; 0) {
  
          fprintf(stderr, "Could not open codec\n");
  
          exit(1);
  
      }
  
  
  
      // print input video stream informataion
  
      // initialize sample scaler
  
  
  
      c->pix_fmt = AV_PIX_FMT_YUV420P;
  
      c->width = 1280;
  
      c->height = 720;
  
      if (vcodec->capabilities &amp; CODEC_CAP_TRUNCATED)
  
          c->flags |= CODEC_FLAG_TRUNCATED;
  
  
  
      c->flags2 |= CODEC_FLAG2_FAST;
  
      int width = 1280;
  
      int height = 720;
  
      SwsContext* swsctx = sws_getCachedContext(nullptr, width,
  
          height, AV_PIX_FMT_YUV420P, width, height, AV_PIX_FMT_RGB32,
  
          SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  }
  
  </vector></iostream>

• I use ffmpeg dinamically to edit a local hosted video to be streamed on iPhone over 3G [on hold]

  3 octobre 2014, par Luchian Chivoiu

  I use ffmpeg dinamically to edit a local hosted video to be streamed on iPhone over 3G .

  I use this line :
  "ffmpeg -i C :\file1.mp4 -s 640x480 -r 30000/1001 -b:a 56k -bt 40k -b:v 50k -maxrate 10M -bufsize 10M -coder 0 -bf 0 -refs 1 -ar 48000 -ab 52k C :\file2.mp4" and it doesn’t work to open on iPhone the transformed file called "file2.mp4".
  I use Web Api and C# to call the ffmpeg locally and the resulted file opens on the browser but still doesn’t want to stream to an iPhone over 3G only if it’s over WiFi.

  Here Apple explains the process but I still didn’t get it work .

  https://developer.apple.com/library/safari/documentation/AppleApplications/Reference/SafariWebContent/CreatingVideoforSafarioniPhone/CreatingVideoforSafarioniPhone.html

  One example that can’t be played on IPhone is this one : http://www.starlety.com/Videos/8ada5277-424a-e411-b2e5-00ff91d7f3dd.mp4